Attachment F

Occupational Safety and Health Admin., Labor

§ 1910.1001

TABLE Z–3—MINERAL DUSTS—Continued
mppcf a

Substance
Inert or Nuisance Dust: d
Respirable fraction .........................................................................................................................
Total dust .......................................................................................................................................

mg/m3

15
50

5 mg/m 3
15 mg/m 3

Note—Conversion factors - mppcf × 35.3 = million particles per cubic meter = particles per c.c.
a Millions of particles per cubic foot of air, based on impinger samples counted by light-field techniques.
b The percentage of crystalline silica in the formula is the amount determined from airborne samples, except in those instances
in which other methods have been shown to be applicable.
c Containing less than 1% quartz; if 1% quartz or more, use quartz limit.
d All inert or nuisance dusts, whether mineral, inorganic, or organic, not listed specifically by substance name are covered by
this limit, which is the same as the Particulates Not Otherwise Regulated (PNOR) limit in Table Z–1.
e Both concentration and percent quartz for the application of this limit are to be determined from the fraction passing a sizeselector with the following characteristics:
Percent passing
selector

Aerodynamic diameter (unit density sphere)
2 ...........................................................................................................................................................................
2.5 ........................................................................................................................................................................
3.5 ........................................................................................................................................................................
5.0 ........................................................................................................................................................................
10 .........................................................................................................................................................................

90
75
50
25
0

The measurements under this note refer to the use of an AEC (now NRC) instrument. The respirable fraction of coal dust is
determined with an MRE; the figure corresponding to that of 2.4 mg/m3 in the table for coal dust is 4.5 mg/m3K.
f This standard applies to any operations or sectors for which the respirable crystalline silica standard, 1910.1053, is stayed or
is otherwise not in effect.

[58 FR 35340, June 30, 1993; 58 FR 40191, July 27, 1993, as amended at 61 FR 56831, Nov. 4, 1996;
62 FR 1600, Jan. 10, 1997; 62 FR 42018, Aug. 4, 1997; 71 FR 10373, Feb. 28, 2006; 71 FR 16673, Apr.
3, 2006; 71 FR 36008, June 23, 2006; 81 FR 16861, Mar. 25, 2016; 81 FR 31167, May 18, 2016]

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§ 1910.1001

tional Safety and Health, U.S. Department of Labor, or designee.
Authorized person means any person
authorized by the employer and required by work duties to be present in
regulated areas.
Building/facility owner is the legal entity, including a lessee, which exercises
control over management and record
keeping functions relating to a building and/or facility in which activities
covered by this standard take place.
Certified industrial hygienist (CIH)
means one certified in the practice of
industrial hygiene by the American
Board of Industrial Hygiene.
Director means the Director of the
National Institute for Occupational
Safety and Health, U.S. Department of
Health and Human Services, or designee.
Employee exposure means that exposure to airborne asbestos that would
occur if the employee were not using
respiratory protective equipment.
Fiber means a particulate form of asbestos 5 micrometers or longer,with a
length-to-diameter ratio of at least 3 to
1.
High-efficiency particulate air (HEPA)
filter means a filter capable of trapping

Asbestos.

(a) Scope and application. (1) This section applies to all occupational exposures to asbestos in all industries covered by the Occupational Safety and
Health Act, except as provided in paragraph (a)(2) and (3) of this section.
(2) This section does not apply to
construction work as defined in 29 CFR
1910.12(b). (Exposure to asbestos in construction work is covered by 29 CFR
1926.1101).
(3) This section does not apply to
ship
repairing,
shipbuilding
and
shipbreaking employments and related
employments as defined in 29 CFR
1915.4. (Exposure to asbestos in these
employments is covered by 29 CFR
1915.1001).
(b) Definitions. Asbestos includes
chrysotile,
amosite,
crocidolite,
tremolite asbestos, anthophyllite asbestos, actinolite asbestos, and any of
these minerals that have been chemically treated and/or altered.
Asbestos-containing material (ACM)
means any material containing more
than 1% asbestos.
Assistant Secretary means the Assistant Secretary of Labor for Occupa-

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§ 1910.1001

29 CFR Ch. XVII (7–1–16 Edition)

and retaining at least 99.97 percent of
0.3 micrometer diameter mono-disperse
particles.
Homogeneous area means an area of
surfacing material or thermal system
insulation that is uniform in color and
texture.
Industrial hygienist means a professional qualified by education, training,
and experience to anticipate, recognize, evaluate and develop controls for
occupational health hazards.
PACM means ‘‘presumed asbestos
containing material.’’
Presumed asbestos containing material
means thermal system insulation and
surfacing material found in buildings
constructed no later than 1980. The designation of a material as ‘‘PACM’’ may
be rebutted pursuant to paragraph
(j)(8) of this section.
Regulated area means an area established by the employer to demarcate
areas where airborne concentrations of
asbestos exceed, or there is a reasonable possibility they may exceed, the
permissible exposure limits.
Surfacing ACM means surfacing material which contains more than 1% asbestos.
Surfacing material means material
that is sprayed, troweled-on or otherwise applied to surfaces (such as acoustical plaster on ceilings and fireproofing materials on structural members, or other materials on surfaces for
acoustical, fireproofing, and other purposes).
Thermal System Insulation (TSI) means
ACM applied to pipes, fittings, boilers,
breeching, tanks, ducts or other structural components to prevent heat loss
or gain.
Thermal System Insulation ACM means
thermal system insulation which contains more than 1% asbestos.
(c) Permissible exposure limit (PELS)—
(1) Time-weighted average limit (TWA).
The employer shall ensure that no employee is exposed to an airborne concentration of asbestos in excess of 0.1
fiber per cubic centimeter of air as an
eight (8)-hour time-weighted average
(TWA) as determined by the method
prescribed in appendix A to this section, or by an equivalent method.
(2) Excursion limit. The employer shall
ensure that no employee is exposed to
an airborne concentration of asbestos

in excess of 1.0 fiber per cubic centimeter of air (1 f/cc) as averaged over a
sampling period of thirty (30) minutes
as determined by the method prescribed in appendix A to this section,
or by an equivalent method.
(d) Exposure monitoring—(1) General.
(i) Determinations of employee exposure shall be made from breathing zone
air samples that are representative of
the 8-hour TWA and 30-minute shortterm exposures of each employee.
(ii) Representative 8-hour TWA employee exposures shall be determined
on the basis of one or more samples
representing full-shift exposures for
each shift for each employee in each
job classification in each work area.
Representative 30-minute short-term
employee exposures shall be determined on the basis of one or more samples representing 30 minute exposures
associated with operations that are
most likely to produce exposures above
the excursion limit for each shift for
each job classification in each work
area.
(2) Initial monitoring. (i) Each employer who has a workplace or work
operation covered by this standard, except as provided for in paragraphs
(d)(2)(ii) and (d)(2)(iii) of this section,
shall perform initial monitoring of employees who are, or may reasonably be
expected to be exposed to airborne concentrations at or above the TWA permissible exposure limit and/or excursion limit.
(ii) Where the employer has monitored after March 31, 1992, for the TWA
permissible exposure limit and/or the
excursion limit, and the monitoring
satisfies all other requirements of this
section, the employer may rely on such
earlier monitoring results to satisfy
the requirements of paragraph (d)(2)(i)
of this section.
(iii) Where the employer has relied
upon objective data that demonstrate
that asbestos is not capable of being released in airborne concentrations at or
above the TWA permissible exposure
limit and/or excursion limit under the
expected conditions of processing, use,
or handling, then no initial monitoring
is required.
(3) Monitoring frequency (periodic monitoring) and patterns. After the initial
determinations required by paragraph

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Occupational Safety and Health Admin., Labor
(d)(2)(i) of this section, samples shall
be of such frequency and pattern as to
represent with reasonable accuracy the
levels of exposure of the employees. In
no case shall sampling be at intervals
greater than six months for employees
whose exposures may reasonably be
foreseen to exceed the TWA permissible exposure limit and/or excursion
limit.
(4) Changes in monitoring frequency. If
either the initial or the periodic monitoring required by paragraphs (d)(2)
and (d)(3) of this section statistically
indicates that employee exposures are
below the TWA permissible exposure
limit and/or excursion limit, the employer may discontinue the monitoring
for those employees whose exposures
are represented by such monitoring.
(5) Additional monitoring. Notwithstanding the provisions of paragraphs
(d)(2)(ii) and (d)(4) of this section, the
employer shall institute the exposure
monitoring required under paragraphs
(d)(2)(i) and (d)(3) of this section whenever there has been a change in the
production, process, control equipment, personnel or work practices that
may result in new or additional exposures above the TWA permissible exposure limit and/or excursion limit or
when the employer has any reason to
suspect that a change may result in
new or additional exposures above the
PEL and/or excursion limit.
(6) Method of monitoring. (i) All samples taken to satisfy the monitoring requirements of paragraph (d) of this section shall be personal samples collected following the procedures specified in appendix A.
(ii) All samples taken to satisfy the
monitoring requirements of paragraph
(d) of this section shall be evaluated
using the OSHA Reference Method
(ORM) specified in appendix A of this
section, or an equivalent counting
method.
(iii) If an equivalent method to the
ORM is used, the employer shall ensure
that the method meets the following
criteria:
(A) Replicate exposure data used to
establish equivalency are collected in
side-by-side field and laboratory comparisons; and
(B) The comparison indicates that
90% of the samples collected in the

§ 1910.1001

range 0.5 to 2.0 times the permissible
limit have an accuracy range of plus or
minus 25 percent of the ORM results at
a 95% confidence level as demonstrated
by a statistically valid protocol; and
(C) The equivalent method is documented and the results of the comparison testing are maintained.
(iv) To satisfy the monitoring requirements of paragraph (d) of this section, employers must use the results of
monitoring analysis performed by laboratories which have instituted quality
assurance programs that include the
elements as prescribed in appendix A of
this section.
(7) Employee notification of monitoring
results. (i) The employer must, within
15 working days after the receipt of the
results of any monitoring performed
under this sections, notify each affected employee of these results either
individually in writing or by posting
the results in an appropriate location
that is accessible to affected employees.
(ii) The written notification required
by paragraph (d)(7)(i) of this section
shall contain the corrective action
being taken by the employer to reduce
employee exposure to or below the
TWA and/or excursion limit, wherever
monitoring results indicated that the
TWA and/or excursion limit had been
exceeded.
(e) Regulated Areas—(1) Establishment.
The employer shall establish regulated
areas wherever airborne concentrations
of asbestos and/or PACM are in excess
of the TWA and/or excursion limit prescribed in paragraph (c) of this section.
(2) Demarcation. Regulated areas shall
be demarcated from the rest of the
workplace in any manner that minimizes the number of persons who will
be exposed to asbestos.
(3) Access. Access to regulated areas
shall be limited to authorized persons
or to persons authorized by the Act or
regulations issued pursuant thereto.
(4) Provision of respirators. Each person entering a regulated area shall be
supplied with and required to use a respirator, selected in accordance with
paragraph (g)(2) of this section.
(5) Prohibited activities. The employer
shall ensure that employees do not eat,
drink, smoke, chew tobacco or gum, or
apply cosmetics in the regulated areas.

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§ 1910.1001

29 CFR Ch. XVII (7–1–16 Edition)

(f) Methods of compliance—(1) Engineering controls and work practices. (i)
The employer shall institute engineering controls and work practices to reduce and maintain employee exposure
to or below the TWA and/or excursion
limit prescribed in paragraph (c) of this
section, except to the extent that such
controls are not feasible.
(ii) Wherever the feasible engineering
controls and work practices that can
be instituted are not sufficient to reduce employee exposure to or below the
TWA and/or excursion limit prescribed
in paragraph (c) of this section, the employer shall use them to reduce employee exposure to the lowest levels
achievable by these controls and shall
supplement them by the use of respiratory protection that complies with
the requirements of paragraph (g) of
this section.
(iii) For the following operations,
wherever feasible engineering controls
and work practices that can be instituted are not sufficient to reduce the
employee exposure to or below the
TWA and/or excursion limit prescribed
in paragraph (c) of this section, the employer shall use them to reduce employee exposure to or below 0.5 fiber
per cubic centimeter of air (as an
eight-hour time-weighted average) or
2.5 fibers/cc for 30 minutes (short-term
exposure) and shall supplement them
by the use of any combination of respiratory protection that complies with
the requirements of paragraph (g) of
this section, work practices and feasible engineering controls that will reduce employee exposure to or below the
TWA and to or below the excursion
limit permissible prescribed in paragraph (c) of this section: Coupling cutoff in primary asbestos cement pipe
manufacturing; sanding in primary and
secondary asbestos cement sheet manufacturing; grinding in primary and
secondary friction product manufacturing; carding and spinning in dry textile processes; and grinding and sanding in primary plastics manufacturing.
(iv) Local exhaust ventilation. Local
exhaust ventilation and dust collection
systems shall be designed, constructed,
installed, and maintained in accordance with good practices such as those
found in the American National Standard Fundamentals Governing the De-

sign and Operation of Local Exhaust
Systems, ANSI Z9.2–1979.
(v) Particular tools. All hand-operated
and power-operated tools which would
produce or release fibers of asbestos,
such as, but not limited to, saws, scorers, abrasive wheels, and drills, shall be
provided with local exhaust ventilation
systems which comply with paragraph
(f)(1)(iv) of this section.
(vi) Wet methods. Insofar as practicable, asbestos shall be handled,
mixed, applied, removed, cut, scored,
or otherwise worked in a wet state sufficient to prevent the emission of airborne fibers so as to expose employees
to levels in excess of the TWA and/or
excursion limit, prescribed in paragraph (c) of this section, unless the
usefulness of the product would be diminished thereby.
(vii) [Reserved]
(viii) Particular products and operations. No asbestos cement, mortar,
coating, grout, plaster, or similar material containing asbestos, shall be removed from bags, cartons, or other
containers in which they are shipped,
without being either wetted, or enclosed, or ventilated so as to prevent
effectively the release of airborne fibers.
(ix) Compressed air. Compressed air
shall not be used to remove asbestos or
materials containing asbestos unless
the compressed air is used in conjunction with a ventilation system which
effectively captures the dust cloud created by the compressed air.
(x) Flooring. Sanding of asbestos-containing flooring material is prohibited.
(2) Compliance program. (i) Where the
TWA and/or excursion limit is exceeded, the employer shall establish and
implement a written program to reduce
employee exposure to or below the
TWA and to or below the excursion
limit by means of engineering and
work practice controls as required by
paragraph (f)(1) of this section, and by
the use of respiratory protection where
required or permitted under this section.
(ii) Such programs shall be reviewed
and updated as necessary to reflect significant changes in the status of the
employer’s compliance program.
(iii) Written programs shall be submitted upon request for examination

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Occupational Safety and Health Admin., Labor
and copying to the Assistant Secretary, the Director, affected employees and designated employee representatives.
(iv) The employer shall not use employee rotation as a means of compliance with the TWA and/or excursion
limit.
(3) Specific compliance methods for
brake and clutch repair:
(i) Engineering controls and work
practices for brake and clutch repair
and service. During automotive brake
and clutch inspection, disassembly, repair and assembly operations, the employer shall institute engineering controls and work practices to reduce employee exposure to materials containing asbestos using a negative pressure enclosure/HEPA vacuum system
method or low pressure/wet cleaning
method, which meets the detailed requirements set out in appendix F to
this section. The employer may also
comply using an equivalent method
which follows written procedures which
the employer demonstrates can achieve
results equivalent to Method A in appendix F to this section. For facilities
in which no more than 5 pair of brakes
or 5 clutches are inspected, disassembled, repaired, or assembled per week,
the method set forth in paragraph [D]
of appendix F to this section may be
used.
(ii) The employer may also comply
by using an equivalent method which
follows written procedures, which the
employer demonstrates can achieve
equivalent exposure reductions as do
the two ‘‘preferred methods.’’ Such
demonstration must include monitoring data conducted under workplace
conditions closely resembling the process, type of asbestos containing materials, control method, work practices
and environmental conditions which
the equivalent method will be used, or
objective data, which document that
under all reasonably foreseeable conditions of brake and clutch repair applications, the method results in exposures which are equivalent to the
methods set out in appendix F to this
section.
(g) Respiratory protection—(1) General.
For employees who use respirators required by this section, the employer
must provide each employee an appro-

§ 1910.1001

priate respirator that complies with
the requirements of this paragraph.
Respirators must be used during:
(i) Periods necessary to install or implement feasible engineering and workpractice controls.
(ii) Work operations, such as maintenance and repair activities, for which
engineering and work-practice controls
are not feasible.
(iii) Work operations for which feasible engineering and work-practice
controls are not yet sufficient to reduce employee exposure to or below the
TWA and/or excursion limit.
(iv) Emergencies.
(2) Respirator program. (i) The employer must implement a respiratory
protection program in accordance with
29 CFR 134 (b) through (d) (except
(d)(1)(iii)), and (f) through (m), which
covers each employee required by this
section to use a respirator.
(ii) Employers must provide an employee with a tight-fitting, powered
air-purifying respirator (PAPR) instead
of a negative pressure respirator selected according to paragraph (g)(3) of
this standard when the employee
chooses to use a PAPR and it provides
adequate protection to the employee.
(iii) No employee must be assigned to
tasks requiring the use of respirators
if, based on their most recent medical
examination, the examining physician
determines that the employee will be
unable to function normally using a
respirator, or that the safety or health
of the employee or other employees
will be impaired by the use of a respirator. Such employees must be assigned to another job or given the opportunity to transfer to a different position, the duties of which they can
perform. If such a transfer position is
available, the position must be with
the same employer, in the same geographical area, and with the same seniority, status, and rate of pay the employee had just prior to such transfer.
(3) Respirator selection. Employers
must:
(i) Select, and provide to employees,
the appropriate respirators specified in
paragraph (d)(3)(i)(A) of 29 CFR
1910.134; however, employers must not
select or use filtering facepiece respirators for protection against asbestos
fibers.

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§ 1910.1001

29 CFR Ch. XVII (7–1–16 Edition)

(ii) Provide HEPA filters for powered
and non-powered air-purifying respirators.
(h) Protective work clothing and equipment—(1) Provision and use. If an employee is exposed to asbestos above the
TWA and/or excursion limit, or where
the possibility of eye irritation exists,
the employer shall provide at no cost
to the employee and ensure that the
employee uses appropriate protective
work clothing and equipment such as,
but not limited to:
(i) Coveralls or similar full-body
work clothing;
(ii) Gloves, head coverings, and foot
coverings; and
(iii) Face shields, vented goggles, or
other appropriate protective equipment which complies with 1910.133 of
this part.
(2) Removal and storage. (i) The employer shall ensure that employees remove work clothing contaminated with
asbestos only in change rooms provided
in accordance with paragraph (i)(1) of
this section.
(ii) The employer shall ensure that
no employee takes contaminated work
clothing out of the change room, except those employees authorized to do
so for the purpose of laundering, maintenance, or disposal.
(iii) Contaminated work clothing
shall be placed and stored in closed
containers which prevent dispersion of
the asbestos outside the container.
(iv) The employer shall ensure that
containers of contaminated protective
devices or work clothing, which are to
be taken out of change rooms or the
workplace for cleaning, maintenance
or disposal, bear labels in accordance
with paragraph (j) of this section.
(3) Cleaning and replacement. (i) The
employer shall clean, launder, repair,
or replace protective clothing and
equipment required by this paragraph
to maintain their effectiveness. The
employer shall provide clean protective
clothing and equipment at least weekly
to each affected employee.
(ii) The employer shall prohibit the
removal of asbestos from protective
clothing and equipment by blowing or
shaking. (iii) Laundering of contaminated clothing shall be done so as to
prevent the release of airborne fibers of
asbestos in excess of the permissible

exposure limits prescribed in paragraph (c) of this section.
(iv) Any employer who gives contaminated clothing to another person
for laundering shall inform such person
of the requirement in paragraph
(h)(3)(iii) of this section to effectively
prevent the release of airborne fibers of
asbestos in excess of the permissible
exposure limits.
(v) The employer shall inform any
person who launders or cleans protective clothing or equipment contaminated with asbestos of the potentially
harmful effects of exposure to asbestos.
(vi) The employer shall ensure that
contaminated clothing is transported
in sealed impermeable bags, or other
closed, impermeable containers, and labeled in accordance with paragraph (j)
of this section.
(i) Hygiene facilities and practices—(1)
Change rooms. (i) The employer shall
provide clean change rooms for employees who work in areas where their
airborne exposure to asbestos is above
the TWA and/or excursion limit.
(ii) The employer shall ensure that
change rooms are in accordance with
1910.141(e) of this part, and are
equipped with two separate lockers or
storage facilities, so separated as to
prevent contamination of the employee’s street clothes from his protective
work clothing and equipment.
(2) Showers. (i) The employer shall ensure that employees who work in areas
where their airborne exposure is above
the TWA and/or excursion limit, shower at the end of the work shift.
(ii) The employer shall provide shower facilities which comply with
1910.141(d)(3) of this part.
(iii) The employer shall ensure that
employees who are required to shower
pursuant to paragraph (i)(2)(i) of this
section do not leave the workplace
wearing any clothing or equipment
worn during the work shift.
(3) Lunchrooms. (i) The employer
shall provide lunchroom facilities for
employees who work in areas where
their airborne exposure is above the
TWA and/or excursion limit.
(ii) The employer shall ensure that
lunchroom facilities have a positive
pressure, filtered air supply, and are
readily accessible to employees.

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Occupational Safety and Health Admin., Labor
(iii) The employer shall ensure that
employees who work in areas where
their airborne exposure is above the
PEL and/or excursion limit wash their
hands and faces prior to eating, drinking or smoking.
(iv) The employer shall ensure that
employees do not enter lunchroom facilities with protective work clothing
or equipment unless surface asbestos
fibers have been removed from the
clothing or equipment by vacuuming or
other method that removes dust without causing the asbestos to become airborne.
(4) Smoking in work areas. The employer shall ensure that employees do
not smoke in work areas where they
are occupationally exposed to asbestos
because of activities in that work area.
(j) Communication of hazards to employees—Introduction. This section applies to the communication of information concerning asbestos hazards in
general industry to facilitate compliance with this standard. Asbestos exposure in general industry occurs in a
wide variety of industrial and commercial settings. Employees who manufacture asbestos-containing products may
be exposed to asbestos fibers. Employees who repair and replace automotive
brakes and clutches may be exposed to
asbestos fibers. In addition, employees
engaged in housekeeping activities in
industrial facilities with asbestos product manufacturing operations, and in
public and commercial buildings with
installed asbestos containing materials
may be exposed to asbestos fibers. Most
of these workers are covered by this
general industry standard, with the exception of state or local governmental
employees in non-state plan states. It
should be noted that employees who
perform housekeeping activities during
and after construction activities are
covered by the asbestos construction
standard, 29 CFR 1926.1101, formerly
1926.58. However, housekeeping employees, regardless of industry designation,
should know whether building components they maintain may expose them
to asbestos. The same hazard communication provisions will protect employees who perform housekeeping operations in all three asbestos standards; general industry, construction,
and shipyard employment. As noted in

§ 1910.1001

the construction standard, building
owners are often the only and/or best
source of information concerning the
presence of previously installed asbestos containing building materials.
Therefore they, along with employers
of potentially exposed employees, are
assigned specific information conveying and retention duties under this
section.
(1) Hazard communication—general. (i)
Chemical manufacturers, importers,
distributors and employers shall comply with all requirements of the Hazard
Communication
Standard
(HCS)
(§ 1910.1200) for asbestos.
(ii) In classifying the hazards of asbestos at least the following hazards
are to be addressed: Cancer and lung effects.
(iii) Employers shall include asbestos
in the hazard communication program
established to comply with the HCS
(§ 1910.1200). Employers shall ensure
that each employee has access to labels
on containers of asbestos and to safety
data sheets, and is trained in accordance with the requirements of HCS and
paragraph (j)(7) of this section.
(2) Installed Asbestos Containing Material. Employers and building owners are
required to treat installed TSI and
sprayed on and troweled-on surfacing
materials as ACM in buildings constructed no later than 1980 for purposes
of this standard. These materials are
designated ‘‘presumed ACM or PACM’’,
and are defined in paragraph (b) of this
section. Asphalt and vinyl flooring material installed no later than 1980 also
must be treated as asbestos-containing.
The employer or building owner may
demonstrate that PACM and flooring
material do not contain asbestos by
complying with paragraph (j)(8)(iii) of
this section.
(3) Duties of employers and building
and facility owners. (i) Building and facility owners shall determine the presence, location, and quantity of ACM
and/or PACM at the work site. Employers and building and facility owners
shall exercise due diligence in complying with these requirements to inform employers and employees about
the presence and location of ACM and
PACM.

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§ 1910.1001

29 CFR Ch. XVII (7–1–16 Edition)
RESPIRATORS AND PROTECTIVE CLOTHING ARE REQUIRED IN THIS AREA

(ii) Building and facility owners shall
maintain records of all information required to be provided pursuant to this
section and/or otherwise known to the
building owner concerning the presence, location and quantity of ACM
and PACM in the building/facility.
Such records shall be kept for the duration of ownership and shall be transferred to successive owners.
(iii) Building and facility owners
shall inform employers of employees,
and employers shall inform employees
who will perform housekeeping activities in areas which contain ACM and/or
PACM of the presence and location of
ACM and/or PACM in such areas which
may be contacted during such activities.
(4) Warning signs—(i) Posting. Warning signs shall be provided and displayed at each regulated area. In addition, warning signs shall be posted at
all approaches to regulated areas so
that an employee may read the signs
and take necessary protective steps before entering the area.
(ii) Sign specifications:
(A) The warning signs required by
paragraph (j)(4)(i) of this section shall
bear the following legend:

(iii) The employer shall ensure that
employees working in and contiguous
to regulated areas comprehend the
warning signs required to be posted by
paragraph (j)(4)(i) of this section.
Means to ensure employee comprehension may include the use of foreign languages, pictographs and graphics.
(iv) At the entrance to mechanical
rooms/areas in which employees reasonably can be expected to enter and
which contain ACM and/or PACM, the
building owner shall post signs which
identify the material which is present,
its location, and appropriate work
practices which, if followed, will ensure
that ACM and/or PACM will not be disturbed. The employer shall ensure, to
the extent feasible, that employees
who come in contact with these signs
can comprehend them. Means to ensure
employee comprehension may include
the use of foreign languages, pictographs, graphics, and awareness training.
(5) Warning labels—(i) Labeling. Labels
shall be affixed to all raw materials,
mixtures, scrap, waste, debris, and
other products containing asbestos fibers, or to their containers. When a
building owner or employer identifies
previously
installed
ACM
and/or
PACM, labels or signs shall be affixed
or posted so that employees will be notified of what materials contain ACM
and/or PACM. The employer shall attach such labels in areas where they
will clearly be noticed by employees
who are likely to be exposed, such as at
the entrance to mechanical room/areas.
Signs required by paragraph (j) of this
section may be posted in lieu of labels
so long as they contain the information required for labeling.
(ii) Label specifications. In addition to
the requirements of paragraph (j)(1),
the employer shall ensure that labels
of bags or containers of protective
clothing and equipment, scrap, waste,
and debris containing asbestos fibers
include the following information:

DANGER
ASBESTOS
MAY CAUSE CANCER
CAUSES DAMAGE TO LUNGS
AUTHORIZED PERSONNEL ONLY

(B) In addition, where the use of respirators and protective clothing is required in the regulated area under this
section, the warning signs shall include
the following:
WEAR RESPIRATORY PROTECTION AND
PROTECTIVE CLOTHING IN THIS AREA

(C) Prior to June 1, 2016, employers
may use the following legend in lieu of
that specified in paragraph (j)(4)(ii)(A)
of this section:

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DANGER
ASBESTOS
CANCER AND LUNG DISEASE
HAZARD
AUTHORIZED PERSONNEL ONLY

DANGER
CONTAINS ASBESTOS FIBERS
MAY CAUSE CANCER
CAUSES DAMAGE TO LUNGS
DO NOT BREATHE DUST
AVOID CREATING DUST

(D) Prior to June 1, 2016, employers
may use the following legend in lieu of
that specified in paragraph (j)(4)(ii)(B)
of this section:

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Occupational Safety and Health Admin., Labor
(iii) Prior to June 1, 2015, employers
may include the following information
on raw materials, mixtures or labels of
bags or containers of protective clothing and equipment, scrap, waste, and
debris containing asbestos fibers in lieu
of the labeling requirements in paragraphs (j)(1)(i) and (j)(5)(ii) of this section:

(D) The engineering controls and
work practices associated with the employee’s job assignment;
(E) The specific procedures implemented to protect employees from exposure to asbestos, such as appropriate
work practices, emergency and cleanup procedures, and personal protective
equipment to be used;
(F) The purpose, proper use, and limitations of respirators and protective
clothing, if appropriate;
(G) The purpose and a description of
the medical surveillance program required by paragraph (l) of this section;
(H) The content of this standard, including appendices.
(I) The names, addresses and phone
numbers of public health organizations
which provide information, materials,
and/or conduct programs concerning
smoking cessation. The employer may
distribute the list of such organizations contained in appendix I to this
section, to comply with this requirement.
(J) The requirements for posting
signs and affixing labels and the meaning of the required legends for such
signs and labels.
(iv) The employer shall also provide,
at no cost to employees who perform
housekeeping operations in an area
which contains ACM or PACM, an asbestos awareness training course,
which shall at a minimum contain the
following elements: health effects of
asbestos, locations of ACM and PACM
in the building/facility, recognition of
ACM and PACM damage and deterioration, requirements in this standard relating to housekeeping, and proper response to fiber release episodes, to all
employees who perform housekeeping
work in areas where ACM and/or PACM
is present. Each such employee shall be
so trained at least once a year.
(v) Access to information and training materials.
(A) The employer shall make a copy
of this standard and its appendices
readily available without cost to all affected employees.
(B) The employer shall provide, upon
request, all materials relating to the
employee information and training
program to the Assistant Secretary
and the training program to the Assistant Secretary and the Director.

DANGER
CONTAINS ASBESTOS FIBERS
AVOID CREATING DUST
CANCER AND LUNG DISEASE HAZARD

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§ 1910.1001

(6) The provisions for labels and for
safety data sheets required by paragraph (j) of this section do not apply
where:
(i) Asbestos fibers have been modified
by a bonding agent, coating, binder, or
other material provided that the manufacturer can demonstrate that during
any reasonably foreseeable use, handling, storage, disposal, processing, or
transportation, no airborne concentrations of fibers of asbestos in excess of
the TWA permissible exposure level
and/or excursion limit will be released
or
(ii) Asbestos is present in a product
in concentrations less than 1.0%.
(7) Employee information and training.
(i) The employer shall train each employee who is exposed to airborne concentrations of asbestos at or above the
PEL and/or excursion limit in accordance with the requirements of this section. The employer shall institute a
training program and ensure employee
participation in the program.
(ii) Training shall be provided prior
to or at the time of initial assignment
and at least annually thereafter.
(iii) The training program shall be
conducted in a manner which the employee is able to understand. The employer shall ensure that each employee
is informed of the following:
(A) The health effects associated
with asbestos exposure;
(B) The relationship between smoking and exposure to asbestos producing
lung cancer:
(C) The quantity, location, manner of
use, release, and storage of asbestos,
and the specific nature of operations
which could result in exposure to asbestos;

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§ 1910.1001

29 CFR Ch. XVII (7–1–16 Edition)

(C) The employer shall inform all employees concerning the availability of
self-help smoking cessation program
material. Upon employee request, the
employer shall distribute such material, consisting of NIH Publication No.
89–1647, or equivalent self-help material, which is approved or published by
a public health organization listed in
appendix I to this section.
(8) Criteria to rebut the designation of
installed material as PACM. (i) At any
time, an employer and/or building
owner may demonstrate, for purposes
of this standard, that PACM does not
contain asbestos. Building owners and/
or employers are not required to communicate information about the presence of building material for which
such a demonstration pursuant to the
requirements of paragraph (j)(8)(ii) of
this section has been made. However,
in all such cases, the information, data
and analysis supporting the determination that PACM does not contain asbestos, shall be retained pursuant to
paragraph (m) of this section.
(ii) An employer or owner may demonstrate that PACM does not contain
asbestos by the following:
(A) Having a completed inspection
conducted pursuant to the requirements of AHERA (40 CFR 763, subpart
E) which demonstrates that no ACM is
present in the material; or
(B) Performing tests of the material
containing PACM which demonstrate
that no ACM is present in the material.
Such tests shall include analysis of
bulk samples collected in the manner
described in 40 CFR 763.86. The tests,
evaluation and sample collection shall
be conducted by an accredited inspector or by a CIH. Analysis of samples
shall be performed by persons or laboratories
with
proficiency
demonstrated by current successful participation in a nationally recognized testing program such as the National Voluntary Laboratory Accreditation Program (NVLAP) or the National Institute for Standards and Technology
(NIST) or the Round Robin for bulk
samples administered by the American
Industrial Hygiene Association (AIHA)
or an equivalent nationally-recognized
round robin testing program.
(iii) The employer and/or building
owner may demonstrate that flooring

material including associated mastic
and backing does not contain asbestos,
by a determination of an industrial hygienist based upon recognized analytical techniques showing that the material is not ACM.
(k) Housekeeping. (1) All surfaces
shall be maintained as free as practicable of ACM waste and debris and
accompanying dust.
(2) All spills and sudden releases of
material containing asbestos shall be
cleaned up as soon as possible.
(3) Surfaces contaminated with asbestos may not be cleaned by the use of
compressed air.
(4)
Vacuuming.
HEPA-filtered
vacuuming equipment shall be used for
vacuuming asbestos containing waste
and debris. The equipment shall be
used and emptied in a manner which
minimizes the reentry of asbestos into
the workplace.
(5) Shoveling, dry sweeping and dry
clean-up of asbestos may be used only
where vacuuming and/or wet cleaning
are not feasible.
(6) Waste disposal. Waste, scrap, debris, bags, containers, equipment, and
clothing contaminated with asbestos
consigned for disposal, shall be collected, recycled and disposed of in
sealed impermeable bags, or other
closed, impermeable containers.
(7) Care of asbestos-containing flooring material.
(i) Sanding of asbestos-containing
floor material is prohibited.
(ii) Stripping of finishes shall be conducted using low abrasion pads at
speeds lower than 300 rpm and wet
methods.
(iii) Burnishing or dry buffing may be
performed only on asbestos-containing
flooring which has sufficient finish so
that the pad cannot contact the asbestos-containing material.
(8) Waste and debris and accompanying dust in an area containing accessible ACM and/or PACM or visibly
deteriorated ACM, shall not be dusted
or swept dry, or vacuumed without
using a HEPA filter.
(l) Medical surveillance—(1) General—
(i) Employees covered. The employer
shall institute a medical surveillance
program for all employees who are or

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Occupational Safety and Health Admin., Labor
will be exposed to airborne concentrations of fibers of asbestos at or above
the TWA and/or excursion limit.
(ii) Examination by a physician. (A)
The employer shall ensure that all
medical examinations and procedures
are performed by or under the supervision of a licensed physician, and shall
be provided without cost to the employee and at a reasonable time and
place.
(B) Persons other than licensed physicians, who administer the pulmonary
function testing required by this section, shall complete a training course
in spirometry sponsored by an appropriate academic or professional institution.
(2) Pre-placement examinations. (i) Before an employee is assigned to an occupation exposed to airborne concentrations of asbestos fibers at or
above the TWA and/or excursion limit,
a pre-placement medical examination
shall be provided or made available by
the employer.
(ii) Such examination shall include,
as a minimum, a medical and work history; a complete physical examination

§ 1910.1001

of all systems with emphasis on the
respiratory system, the cardiovascular
system and digestive tract; completion
of the respiratory disease standardized
questionnaire in appendix D to this
section, part 1; a chest roentgenogram
(posterior-anterior 14 × 17 inches); pulmonary function tests to include forced
vital capacity (FVC) and forced expiratory volume at 1 second (FEV(1.0)); and
any additional tests deemed appropriate by the examining physician. Interpretation and classification of chest
roentgenogram shall be conducted in
accordance with appendix E to this section.
(3) Periodic examinations. (i) Periodic
medical examinations shall be made
available annually.
(ii) The scope of the medical examination shall be in conformance with
the protocol established in paragraph
(l)(2)(ii) of this section, except that the
frequency of chest roentgenogram shall
be conducted in accordance with Table
1, and the abbreviated standardized
questionnaire contained in, part 2 of
appendix D to this section shall be administered to the employee.

TABLE 1—FREQUENCY OF CHEST ROENTGENOGRAM
Age of employee
Years since first exposure

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0 to 10 .............................................................
10 + .................................................................

15 to 35

35 + to 45

Every 5 years ...................
Every 5 years ...................

Every 5 years ...................
Every 2 years ...................

(4) Termination of employment examinations. (i) The employer shall provide,
or make available, a termination of
employment medical examination for
any employee who has been exposed to
airborne concentrations of fibers of asbestos at or above the TWA and/or excursion limit.
(ii) The medical examination shall be
in accordance with the requirements of
the periodic examinations stipulated in
paragraph (l)(3) of this section, and
shall be given within 30 calendar days
before or after the date of termination
of employment.
(5) Recent examinations. No medical
examination is required of any employee, if adequate records show that
the employee has been examined in accordance with any of paragraphs ((l)(2)
through (l)(4)) of this section within

45 +

the past 1 year period. A pre- employment medical examination which was
required as a condition of employment
by the employer, may not be used by
that employer to meet the requirements of this paragraph, unless the
cost of such examination is borne by
the employer.
(6) Information provided to the physician. The employer shall provide the
following information to the examining physician:
(i) A copy of this standard and Appendices D and E.
(ii) A description of the affected employee’s duties as they relate to the
employee’s exposure.
(iii) The employee’s representative
exposure level or anticipated exposure
level.

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Every 5 years.
Every 1 year.

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§ 1910.1001

29 CFR Ch. XVII (7–1–16 Edition)

(iv) A description of any personal
protective and respiratory equipment
used or to be used.
(v) Information from previous medical examinations of the affected employee that is not otherwise available
to the examining physician.
(7) Physician’s written opinion. (i) The
employer shall obtain a written opinion from the examining physician. This
written opinion shall contain the results of the medical examination and
shall include:
(A) The physician’s opinion as to
whether the employee has any detected
medical conditions that would place
the employee at an increased risk of
material health impairment from exposure to asbestos;
(B) Any recommended limitations on
the employee or upon the use of personal protective equipment such as
clothing or respirators;
(C) A statement that the employee
has been informed by the physician of
the results of the medical examination
and of any medical conditions resulting
from asbestos exposure that require
further explanation or treatment; and
(D) A statement that the employee
has been informed by the physician of
the increased risk of lung cancer attributable to the combined effect of
smoking and asbestos exposure.
(ii) The employer shall instruct the
physician not to reveal in the written
opinion given to the employer specific
findings or diagnoses unrelated to occupational exposure to asbestos.
(iii) The employer shall provide a
copy of the physician’s written opinion
to the affected employee within 30 days
from its receipt.
(m) Recordkeeping—(1) Exposure measurements.

(B) The operation involving exposure
to asbestos which is being monitored;
(C) Sampling and analytical methods
used and evidence of their accuracy;
(D) Number, duration, and results of
samples taken;
(E) Type of respiratory protective devices worn, if any; and
(F) Name, social security number and
exposure of the employees whose exposure are represented.
(iii) The employer shall maintain
this record for at least thirty (30)
years, in accordance with 29 CFR
1910.20.
(2) Objective data for exempted operations. (i) Where the processing, use, or
handling of products made from or containing asbestos is exempted from
other requirements of this section
under paragraph (d)(2)(iii) of this section, the employer shall establish and
maintain an accurate record of objective data reasonably relied upon in support of the exemption.
(ii) The record shall include at least
the following:
(A) The product qualifying for exemption;
(B) The source of the objective data;
(C) The testing protocol, results of
testing, and/or analysis of the material
for the release of asbestos;
(D) A description of the operation exempted and how the data support the
exemption; and
(E) Other data relevant to the operations, materials, processing, or employee exposures covered by the exemption.
(iii) The employer shall maintain
this record for the duration of the employer’s reliance upon such objective
data.
(3) Medical surveillance. (i) The employer shall establish and maintain an
accurate record for each employee subject to medical surveillance by paragraph (l)(1)(i) of this section, in accordance with 29 CFR 1910.1020.
(ii) The record shall include at least
the following information:
(A) The name and social security
number of the employee;
(B) Physician’s written opinions;
(C) Any employee medical complaints related to exposure to asbestos;
and

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NOTE: The employer may utilize the services of competent organizations such as industry trade associations and employee associations to maintain the records required by
this section.

(i) The employer shall keep an accurate record of all measurements taken
to monitor employee exposure to asbestos as prescribed in paragraph (d) of
this section.
(ii) This record shall include at least
the following information:
(A) The date of measurement;

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Occupational Safety and Health Admin., Labor

§ 1910.1001

(o) Appendices. (1) Appendices A, C, D,
E, and F to this section are incorporated as part of this section and the
contents of these Appendices are mandatory.
(2) Appendices B, G, H, I, and J to
this section are informational and are
not intended to create any additional
obligations not otherwise imposed or
to detract from any existing obligations.

(D) A copy of the information provided to the physician as required by
paragraph (l)(6) of this section.
(iii) The employer shall ensure that
this record is maintained for the duration of employment plus thirty (30)
years, in accordance with 29 CFR
1910.1020.
(4) Training. The employer shall
maintain all employee training records
for one (1) year beyond the last date of
employment of that employee.
(5) Availability. (i) The employer,
upon written request, shall make all
records required to be maintained by
this section available to the Assistant
Secretary and the Director for examination and copying.
(ii) The employer, upon request shall
make any exposure records required by
paragraph (m)(1) of this section available for examination and copying to affected employees, former employees,
designated representatives and the Assistant Secretary, in accordance with
29 CFR 1910.1020 (a) through (e) and (g)
through (i).
(iii) The employer, upon request,
shall make employee medical records
required by paragraph (m)(3) of this
section available for examination and
copying to the subject employee, to
anyone having the specific written consent of the subject employee, and the
Assistant Secretary, in accordance
with 29 CFR 1910.1020.
(6) Transfer of records. The employer
shall comply with the requirements
concerning transfer of records set forth
in 29 CFR 1910.1020(h).
(n) Observation of monitoring—(1) Employee observation. The employer shall
provide affected employees or their
designated representatives an opportunity to observe any monitoring of
employee exposure to asbestos conducted in accordance with paragraph
(d) of this section.
(2) Observation procedures. When observation of the monitoring of employee exposure to asbestos requires
entry into an area where the use of
protective clothing or equipment is required, the observer shall be provided
with and be required to use such clothing and equipment and shall comply
with all other applicable safety and
health procedures.

APPENDIX A TO § 1910.1001—OSHA REFERENCE
METHOD—MANDATORY
This mandatory appendix specifies the procedure for analyzing air samples for asbestos
and specifies quality control procedures that
must be implemented by laboratories performing the analysis. The sampling and analytical methods described below represent
the elements of the available monitoring
methods (such as appendix B of their regulation, the most current version of the OSHA
method ID–160, or the most current version
of the NIOSH Method 7400). All employers
who are required to conduct air monitoring
under paragraph (d) of the standard are required to utilize analytical laboratories that
use this procedure, or an equivalent method,
for collecting and analyzing samples.
Sampling and Analytical Procedure
1. The sampling medium for air samples
shall be mixed cellulose ester filter membranes. These shall be designated by the
manufacturer as suitable for asbestos counting. See below for rejection of blanks.
2. The preferred collection device shall be
the 25-mm diameter cassette with an openfaced 50-mm electrically conductive extension cowl. The 37-mm cassette may be used if
necessary but only if written justification
for the need to use the 37-mm filter cassette
accompanies the sample results in the employee’s exposure monitoring record. Do not
reuse or reload cassettes for asbestos sample
collection.
3. An air flow rate between 0.5 liter/min
and 2.5 liters/min shall be selected for the 25mm cassette. If the 37-mm cassette is used,
an air flow rate between 1 liter/min and 2.5
liters/min shall be selected.
4. Where possible, a sufficient air volume
for each air sample shall be collected to
yield between 100 and 1,300 fibers per square
millimeter on the membrane filter. If a filter
darkens in appearance or if loose dust is seen
on the filter, a second sample shall be started.
5. Ship the samples in a rigid container
with sufficient packing material to prevent
dislodging the collected fibers. Packing material that has a high electrostatic charge on

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§ 1910.1001

29 CFR Ch. XVII (7–1–16 Edition)

its surface (e.g., expanded polystyrene) cannot be used because such material can cause
loss of fibers to the sides of the cassette.
6. Calibrate each personal sampling pump
before and after use with a representative filter cassette installed between the pump and
the calibration devices.
7. Personal samples shall be taken in the
‘‘breathing zone’’ of the employee (i.e., attached to or near the collar or lapel near the
worker’s face).
8. Fiber counts shall be made by positive
phase contrast using a microscope with an 8
to 10× eyepiece and a 40 to 45× objective for
a total magnification of approximately 400×
and a numerical aperture of 0.65 to 0.75. The
microscope shall also be fitted with a green
or blue filter.
9. The microscope shall be fitted with a
Walton-Beckett eyepiece graticule calibrated for a field diameter of 100 micrometers (±2 micrometers).
10. The phase-shift detection limit of the
microscope shall be about 3 degrees measured using the HSE phase shift test slide as
outlined below.
a. Place the test slide on the microscope
stage and center it under the phase objective.
b. Bring the blocks of grooved lines into
focus.

an equivalent index of refraction and similar
clarity.
13. Observe the following counting rules.
a. Count only fibers equal to or longer than
5 micrometers. Measure the length of curved
fibers along the curve.
b. In the absence of other information,
count all particles as asbesto that have a
length-to-width ratio (aspect ratio) of 3:1 or
greater.
c. Fibers lying entirely within the boundary of the Walton-Beckett graticule field
shall receive a count of 1. Fibers crossing the
boundary once, having one end within the
circle, shall receive the count of one half
(1⁄2). Do not count any fiber that crosses the
graticule boundary more than once. Reject
and do not count any other fibers even
though they may be visible outside the graticule area.
d. Count bundles of fibers as one fiber unless individual fibers can be identified by observing both ends of an individual fiber.
e. Count enough graticule fields to yield
100 fibers. Count a minimum of 20 fields; stop
counting at 100 fields regardless of fiber
count.
14. Blind recounts shall be conducted at
the rate of 10 percent.
Quality Control Procedures
1. Intralaboratory program. Each laboratory and/or each company with more than
one microscopist counting slides shall establish a statistically designed quality assurance program involving blind recounts and
comparisons between microscopists to monitor the variability of counting by each
microscopist and between microscopists. In a
company with more than one laboratory, the
program shall include all laboratories and
shall also evaluate the laboratory-to-laboratory variability.
2.a. Interlaboratory program. Each laboratory analyzing asbestos samples for compliance determination shall implement an
interlaboratory quality assurance program
that as a minimum includes participation of
at least two other independent laboratories.
Each laboratory shall participate in round
robin testing at least once every 6 months
with at least all the other laboratories in its
interlaboratory quality assurance group.
Each laboratory shall submit slides typical
of its own work load for use in this program.
The round robin shall be designed and results
analyzed using appropriate statistical methodology.
2.b. All laboratories should also participate
in a national sample testing scheme such as
the Proficiency Analytical Testing Program
(PAT), or the Asbestos Registry sponsored by
the American Industrial Hygiene Association
(AIHA).
3. All individuals performing asbestos analysis must have taken the NIOSH course for

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NOTE: The slide consists of seven sets of
grooved lines (ca. 20 grooves to each block)
in descending order of visibility from sets 1
to 7, seven being the least visible. The requirements for asbestos counting are that
the microscope optics must resolve the
grooved lines in set 3 completely, although
they may appear somewhat faint, and that
the grooved lines in sets 6 and 7 must be invisible. Sets 4 and 5 must be at least partially visible but may vary slightly in visibility between microscopes. A microscope
that fails to meet these requirements has either too low or too high a resolution to be
used for asbestos counting.
c. If the image deteriorates, clean and adjust the microscope optics. If the problem
persists, consult the microscope manufacturer.
11. Each set of samples taken will include
10% field blanks or a minimum of 2 field
blanks. These blanks must come from the
same lot as the filters used for sample collection. The field blank results shall be averaged and subtracted from the analytical results before reporting. A set consists of any
sample or group of samples for which an
evaluation for this standard must be made.
Any samples represented by a field blank
having a fiber count in excess of the detection limit of the method being used shall be
rejected.
12. The samples shall be mounted by the
acetone/triacetin method or a method with

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Occupational Safety and Health Admin., Labor

Asbestos Fiber: A fiber of asbestos which
meets the criteria specified below for a fiber.
Aspect Ratio: The ratio of the length of a
fiber to it’s diameter (e.g. 3:1, 5:1 aspect ratios).
Cleavage Fragments: Mineral particles
formed by comminution of minerals, especially those characterized by parallel sides
and a moderate aspect ratio (usually less
than 20:1).
Detection Limit: The number of fibers necessary to be 95% certain that the result is
greater than zero.
Differential Counting: The term applied to
the practice of excluding certain kinds of fibers from the fiber count because they do
not appear to be asbestos.
Fiber: A particle that is 5 μm or longer,
with a length-to-width ratio of 3 to 1 or
longer.
Field: The area within the graticule circle
that is superimposed on the microscope
image.
Set: The samples which are taken, submitted to the laboratory, analyzed, and for
which, interim or final result reports are
generated.
Tremolite, Anthophyllite, and Actinolite: The
non-asbestos form of these minerals which
meet the definition of a fiber. It includes any
of these minerals that have been chemically
treated and/or altered.
Walton-Beckett Graticule: An eyepiece graticule specifically designed for asbestos fiber
counting. It consists of a circle with a projected diameter of 100 2 μm (area of about
0.00785 mm2) with a crosshair having ticmarks at 3-μm intervals in one direction and
5-μm in the orthogonal direction. There are
marks around the periphery of the circle to
demonstrate the proper sizes and shapes of
fibers. This design is reproduced in Figure 1.
The disk is placed in one of the microscope
eyepieces so that the design is superimposed
on the field of view.

sampling and evaluating airborne asbestos
dust or an equalivalent course.
4. When the use of different microscopes
contributes to differences between counters
and laboratories, the effect of the different
microscope shall be evaluated and the microscope shall be replaced, as necessary.
5. Current results of these quality assurance programs shall be posted in each laboratory to keep the microscopists informed.
APPENDIX B TO § 1910.1001—DETAILED PROCEDURES FOR ASBESTOS SAMPLING AND ANALYSIS—NON-MANDATORY
Matrix Air:
OSHA Permissible Exposure
Limits:
Time Weighted Average ...... 0.1 fiber/cc
Excursion Level (30 min- 1.0 fiber/cc
utes).
Collection Procedure:
A known volume of air is drawn through a 25-mm diameter
cassette containing a mixed-cellulose ester filter. The cassette must be equipped with an electrically conductive 50mm extension cowl. The sampling time and rate are chosen
to give a fiber density of between 100 to 1,300 fibers/mm2
on the filter.
Recommended Sampling Rate .......... 0.5 to 5.0 liters/minute
(L/min)
Recommended Air Volumes:
Minimum .............................. 25 L
Maximum ............................. 2,400 L

Analytical Procedure: A portion of the
sample filter is cleared and prepared for asbestos fiber counting by Phase Contrast Microscopy (PCM) at 400X.
Commercial manufacturers and products
mentioned in this method are for descriptive
use only and do not constitute endorsements
by USDOL-OSHA. Similar products from
other sources can be substituted.
1. Introduction

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§ 1910.1001

This method describes the collection of
airborne asbestos fibers using calibrated
sampling pumps with mixed-cellulose ester
(MCE) filters and analysis by phase contrast
microscopy (PCM). Some terms used are
unique to this method and are defined below:
Asbestos: A term for naturally occurring fibrous minerals. Asbestos includes chrysotile,
crocidolite,
amosite
(cummingtonitegrunerite asbestos), tremolite asbestos, actinolite asbestos, anthophyllite asbestos, and
any of these minerals that have been chemically treated and/or altered. The precise
chemical formulation of each species will
vary with the location from which it was
mined. Nominal compositions are listed:
Chrysotile ................ Mg3 Si2 O5(OH)4
Crocidolite ............... Na2 Fe32 + Fe23 + Si8
O22 (OH)2
Amosite .................... (Mg,Fe)7 Si8 O22 (OH)2
Tremolite-actinolite
Ca2(Mg,Fe)5 Si8 O22
(OH)2
Anthophyllite .......... (Mg,Fe)7 Si8 O22 (OH)2

1.1. History
Early surveys to determine asbestos exposures were conducted using impinger counts
of total dust with the counts expressed as
million particles per cubic foot. The British
Asbestos Research Council recommended filter membrane counting in 1969. In July 1969,
the Bureau of Occupational Safety and
Health published a filter membrane method
for counting asbestos fibers in the United
States. This method was refined by NIOSH
and published as P CAM 239. On May 29, 1971,
OSHA specified filter membrane sampling
with phase contrast counting for evaluation
of asbestos exposures at work sites in the
United States. The use of this technique was
again required by OSHA in 1986. Phase contrast microscopy has continued to be the
method of choice for the measurement of occupational exposure to asbestos.

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§ 1910.1001

29 CFR Ch. XVII (7–1–16 Edition)
1.2. Principle

1.5. Physical Properties

Air is drawn through a MCE filter to capture airborne asbestos fibers. A wedge shaped
portion of the filter is removed, placed on a
glass microscope slide and made transparent.
A measured area (field) is viewed by PCM.
All the fibers meeting defined criteria for asbestos are counted and considered a measure
of the airborne asbestos concentration.

Asbestos fiber possesses a high tensile
strength along its axis, is chemically inert,
non-combustible, and heat resistant. It has a
high electrical resistance and good sound absorbing properties. It can be weaved into cables, fabrics or other textiles, and also matted into asbestos papers, felts, or mats.

1.3. Advantages and Disadvantages

2.1. The ideal counting range on the filter
is 100 to 1,300 fibers/mm2. With a WaltonBeckett graticule this range is equivalent to
0.8 to 10 fibers/field. Using NIOSH counting
statistics, a count of 0.8 fibers/field would
give an approximate coefficient of variation
(CV) of 0.13.
2.2. The detection limit for this method is
4.0 fibers per 100 fields or 5.5 fibers/mm2. This
was determined using an equation to estimate the maximum CV possible at a specific
concentration (95% confidence) and a Lower
Control Limit of zero. The CV value was
then used to determine a corresponding concentration from historical CV vs fiber relationships. As an example:
Lower Control Limit (95% Confidence) = AC
¥ 1.645(CV)(AC)
Where:
AC = Estimate of the airborne fiber concentration (fibers/cc) Setting the Lower
Control Limit = 0 and solving for CV:
0 = AC ¥ 1.645(CV)(AC)
CV = 0.61
This value was compared with CV vs. count
curves. The count at which CV = 0.61 for
Leidel-Busch counting statistics or for an
OSHA Salt Lake Technical Center (OSHASLTC) CV curve (see appendix A for further
information) was 4.4 fibers or 3.9 fibers per
100 fields, respectively. Although a lower detection limit of 4 fibers per 100 fields is supported by the OSHA-SLTC data, both data
sets support the 4.5 fibers per 100 fields value.

2. Range and Detection Limit

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There are four main advantages of PCM
over other methods:
(1) The technique is specific for fibers.
Phase contrast is a fiber counting technique
which excludes non-fibrous particles from
the analysis.
(2) The technique is inexpensive and does
not require specialized knowledge to carry
out the analysis for total fiber counts.
(3) The analysis is quick and can be performed on-site for rapid determination of air
concentrations of asbestos fibers.
(4) The technique has continuity with historical epidemiological studies so that estimates of expected disease can be inferred
from long-term determinations of asbestos
exposures.
The main disadvantage of PCM is that it
does not positively identify asbestos fibers.
Other fibers which are not asbestos may be
included in the count unless differential
counting is performed. This requires a great
deal of experience to adequately differentiate asbestos from non-asbestos fibers. Positive identification of asbestos must be performed by polarized light or electron microscopy techniques. A further disadvantage of
PCM is that the smallest visible fibers are
about 0.2 μm in diameter while the finest asbestos fibers may be as small as 0.02 μm in
diameter. For some exposures, substantially
more fibers may be present than are actually
counted.
1.4. Workplace Exposure

3. Method Performance—Precision and
Accuracy

Asbestos is used by the construction industry in such products as shingles, floor tiles,
asbestos cement, roofing felts, insulation
and acoustical products. Non-construction
uses include brakes, clutch facings, paper,
paints, plastics, and fabrics. One of the most
significant exposures in the workplace is the
removal and encapsulation of asbestos in
schools, public buildings, and homes. Many
workers have the potential to be exposed to
asbestos during these operations.
About 95% of the asbestos in commercial
use in the United States is chrysotile. Crocidolite and amosite make up most of the remainder. Anthophyllite and tremolite or actinolite are likely to be encountered as contaminants in various industrial products.

Precision is dependent upon the total number of fibers counted and the uniformity of
the fiber distribution on the filter. A general
rule is to count at least 20 and not more than
100 fields. The count is discontinued when 100
fibers are counted, provided that 20 fields
have already been counted. Counting more
than 100 fibers results in only a small gain in
precision. As the total count drops below 10
fibers, an accelerated loss of precision is
noted.
At this time, there is no known method to
determine the absolute accuracy of the asbestos analysis. Results of samples prepared
through the Proficiency Analytical Testing
(PAT) Program and analyzed by the OSHASLTC showed no significant bias when compared to PAT reference values. The PAT

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Occupational Safety and Health Admin., Labor

5.2.1. Seal the point where the base and
cowl of each cassette meet with a gel band or
tape.
5.2.2. Charge the pumps completely before
beginning.
5.2.3. Connect each pump to a calibration
cassette with an appropriate length of 6-mm
bore plastic tubing. Do not use luer connectors—the type of cassette specified above has
built-in adapters.
5.2.4. Select an appropriate flow rate for
the situation being monitored. The sampling
flow rate must be between 0.5 and 5.0 L/min
for personal sampling and is commonly set
between 1 and 2 L/min. Always choose a flow
rate that will not produce overloaded filters.
5.2.5. Calibrate each sampling pump before
and after sampling with a calibration cassette in-line (Note: This calibration cassette
should be from the same lot of cassettes used
for sampling). Use a primary standard (e.g.
bubble burette) to calibrate each pump. If
possible, calibrate at the sampling site.
NOTE: If sampling site calibration is not
possible, environmental influences may affect the flow rate. The extent is dependent
on the type of pump used. Consult with the
pump manufacturer to determine dependence
on environmental influences. If the pump is
affected by temperature and pressure
changes, correct the flow rate using the formula shown in the section ‘‘Sampling Pump
Flow Rate Corrections’’ at the end of this appendix.
5.2.6. Connect each pump to the base of
each sampling cassette with flexible tubing.
Remove the end cap of each cassette and
take each air sample open face. Assure that
each sample cassette is held open side down
in the employee’s breathing zone during
sampling. The distance from the nose/mouth
of the employee to the cassette should be
about 10 cm. Secure the cassette on the collar or lapel of the employee using spring
clips or other similar devices.
5.2.7. A suggested minimum air volume
when sampling to determine TWA compliance is 25 L. For Excursion Limit (30 min
sampling time) evaluations, a minimum air
volume of 48 L is recommended.
5.2.8. The most significant problem when
sampling for asbestos is overloading the filter with non-asbestos dust. Suggested maximum air sample volumes for specific environments are:

samples were analyzed from 1987 to 1989 (N =
36) and the concentration range was from 120
to 1,300 fibers/mm2.
4. Interferences
Fibrous substances, if present, may interfere with asbestos analysis.
Some common fibers are:
fiberglass
anhydrite
plant fibers
perlite veins
gypsum
some synthetic fibers
membrane structures
sponge spicules
diatoms
microorganisms
wollastonite
The use of electron microscopy or optical
tests such as polarized light, and dispersion
staining may be used to differentiate these
materials from asbestos when necessary.
5. Sampling
5.1. Equipment

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§ 1910.1001

5.1.1. Sample assembly (The assembly is
shown in Figure 3). Conductive filter holder
consisting of a 25-mm diameter, 3-piece cassette having a 50-mm long electrically conductive extension cowl. Backup pad, 25-mm,
cellulose. Membrane filter, mixed-cellulose
ester (MCE), 25-mm, plain, white, 0.4 to 1.2μm pore size.
NOTES: (a) Do not re-use cassettes.
(b) Fully conductive cassettes are required
to reduce fiber loss to the sides of the cassette due to electrostatic attraction.
(c) Purchase filters which have been selected by the manufacturer for asbestos
counting or analyze representative filters for
fiber background before use. Discard the filter lot if more than 4 fibers/100 fields are
found.
(d) To decrease the possibility of contamination, the sampling system (filter-backup
pad-cassette)
for
asbestos
is
usually
preassembled by the manufacturer.
(e) Other cassettes, such as the Bellmouth, may be used within the limits of
their validation.
5.1.2. Gel bands for sealing cassettes.
5.1.3. Sampling pump.
Each pump must be a battery operated,
self-contained unit small enough to be
placed on the monitored employee and not
interfere with the work being performed. The
pump must be capable of sampling at the collection rate for the required sampling time.
5.1.4. Flexible tubing, 6-mm bore.
5.1.5. Pump calibration.
Stopwatch and bubble tube/burette or electronic meter.
5.2. Sampling Procedure

Environment

Air vol. (L)

Asbestos removal operations (visible dust) .......
Asbestos removal operations (little dust) ...........
Office environments ...........................................

Caution: Do not overload the filter with
dust. High levels of non-fibrous dust particles may obscure fibers on the filter and

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§ 1910.1001

29 CFR Ch. XVII (7–1–16 Edition)

lower the count or make counting impossible. If more than about 25 to 30% of the
field area is obscured with dust, the result
may be biased low. Smaller air volumes may
be necessary when there is excessive non-asbestos dust in the air.
While sampling, observe the filter with a
small flashlight. If there is a visible layer of
dust on the filter, stop sampling, remove and
seal the cassette, and replace with a new
sampling assembly. The total dust loading
should not exceed 1 mg.
5.2.9. Blank samples are used to determine
if any contamination has occurred during
sample handling. Prepare two blanks for the
first 1 to 20 samples. For sets containing
greater than 20 samples, prepare blanks as
10% of the samples. Handle blank samples in
the same manner as air samples with one exception: Do not draw any air through the
blank samples. Open the blank cassette in
the place where the sample cassettes are
mounted on the employee. Hold it open for
about 30 seconds. Close and seal the cassette
appropriately. Store blanks for shipment
with the sample cassettes.
5.2.10. Immediately after sampling, close
and seal each cassette with the base and
plastic plugs. Do not touch or puncture the
filter membrane as this will invalidate the
analysis.
5.2.11 Attach and secure a sample seal
around each sample cassette in such a way
as to assure that the end cap and base plugs
cannot be removed without destroying the
seal. Tape the ends of the seal together since
the seal is not long enough to be wrapped
end-to-end. Also wrap tape around the cassette at each joint to keep the seal secure.

any open flame. For generation of acetone
vapor, use a spark free heat source.
6.1.2. Any asbestos spills should be cleaned
up immediately to prevent dispersal of fibers. Prudence should be exercised to avoid
contamination of laboratory facilities or exposure of personnel to asbestos. Asbestos
spills should be cleaned up with wet methods
and/or a High Efficiency Particulate-Air
(HEPA) filtered vacuum.
Caution: Do not use a vacuum without a
HEPA filter—It will disperse fine asbestos fibers in the air.
6.2. Equipment
6.2.1. Phase contrast microscope with binocular or trinocular head.
6.2.2. Widefield or Huygenian 10X eyepieces
(NOTE: The eyepiece containing the graticule
must be a focusing eyepiece. Use a 40X phase
objective with a numerical aperture of 0.65 to
0.75).
6.2.3. Kohler illumination (if possible) with
green or blue filter.
6.2.4. Walton-Beckett Graticule, type G–22
with 100 ±2 μm projected diameter.
6.2.5. Mechanical stage.
A rotating mechanical stage is convenient
for use with polarized light.
6.2.6. Phase telescope.
6.2.7. Stage micrometer with 0.01–mm subdivisions.
6.2.8. Phase-shift test slide, mark II (Available from PTR optics Ltd., and also
McCrone).
6.2.9. Precleaned glass slides, 25 mm × 75
mm. One end can be frosted for convenience
in writing sample numbers, etc., or paste-on
labels can be used.
6.2.10. Cover glass #1 1⁄2.
6.2.11. Scalpel (#10, curved blade).
6.2.12. Fine tipped forceps.
6.2.13. Aluminum block for clearing filter
(see appendix D and Figure 4).
6.2.14. Automatic adjustable pipette, 100- to
500-μL.
6.2.15. Micropipette, 5 μL.

5.3. Sample Shipment
5.3.1. Send the samples to the laboratory
with paperwork requesting asbestos analysis.
List any known fibrous interferences present
during sampling on the paperwork. Also,
note the workplace operation(s) sampled.
5.3.2. Secure and handle the samples in
such that they will not rattle during shipment nor be exposed to static electricity. Do
not ship samples in expanded polystyrene
peanuts, vermiculite, paper shreds, or excelsior. Tape sample cassettes to sheet bubbles
and place in a container that will cushion
the samples in such a manner that they will
not rattle.
5.3.3. To avoid the possibility of sample
contamination, always ship bulk samples in
separate mailing containers.

6.3. Reagents
6.3.1. Acetone (HPLC grade).
6.3.2. Triacetin (glycerol triacetate).
6.3.3. Lacquer or nail polish.
6.4. Standard Preparation
A way to prepare standard asbestos samples of known concentration has not been developed. It is possible to prepare replicate
samples of nearly equal concentration. This
has been performed through the PAT program. These asbestos samples are distributed
by the AIHA to participating laboratories.
Since only about one-fourth of a 25–mm
sample membrane is required for an asbestos
count, any PAT sample can serve as a
‘‘standard’’ for replicate counting.

6. Analysis

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6.1. Safety Precautions
6.1.1. Acetone is extremely flammable and
precautions must be taken not to ignite it.
Avoid using large containers or quantities of
acetone. Transfer the solvent in a ventilated
laboratory hood. Do not use acetone near

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lpowell on DSK54DXVN1OFR with $$_JOB

Occupational Safety and Health Admin., Labor

§ 1910.1001

6.5. Sample Mounting

6.6. Sample Analysis

NOTE: See Safety Precautions in Section
6.1. before proceeding. The objective is to
produce samples with a smooth (non-grainy)
background in a medium with a refractive
index of approximately 1.46. The technique
below collapses the filter for easier focusing
and produces permanent mounts which are
useful for quality control and interlaboratory comparison.
An aluminum block or similar device is required for sample preparation.
6.5.1. Heat the aluminum block to about 70
°C. The hot block should not be used on any
surface that can be damaged by either the
heat or from exposure to acetone.
6.5.2. Ensure that the glass slides and cover
glasses are free of dust and fibers.
6.5.3. Remove the top plug to prevent a
vacuum when the cassette is opened. Clean
the outside of the cassette if necessary. Cut
the seal and/or tape on the cassette with a
razor blade. Very carefully separate the base
from the extension cowl, leaving the filter
and backup pad in the base.
6.5.4. With a rocking motion cut a triangular wedge from the filter using the scalpel. This wedge should be one-sixth to onefourth of the filter. Grasp the filter wedge
with the forceps on the perimeter of the filter which was clamped between the cassette
pieces. DO NOT TOUCH the filter with your
finger. Place the filter on the glass slide
sample side up. Static electricity will usually keep the filter on the slide until it is
cleared.
6.5.5. Place the tip of the micropipette containing about 200 μL acetone into the aluminum block. Insert the glass slide into the
receiving slot in the aluminum block. Inject
the acetone into the block with slow, steady
pressure on the plunger while holding the pipette firmly in place. Wait 3 to 5 seconds for
the filter to clear, then remove the pipette
and slide from the aluminum block.
6.5.6. Immediately (less than 30 seconds)
place 2.5 to 3.5 μL of triacetin on the filter
(Note: Waiting longer than 30 seconds will
result in increased index of refraction and
decreased contrast between the fibers and
the preparation. This may also lead to separation of the cover slip from the slide).
6.5.7. Lower a cover slip gently onto the filter at a slight angle to reduce the possibility
of forming air bubbles. If more than 30 seconds have elapsed between acetone exposure
and triacetin application, glue the edges of
the cover slip to the slide with lacquer or
nail polish.
6.5.8. If clearing is slow, warm the slide for
15 min on a hot plate having a surface temperature of about 50 °C to hasten clearing.
The top of the hot block can be used if the
slide is not heated too long.
6.5.9. Counting may proceed immediately
after clearing and mounting are completed.

Completely align the microscope according
to the manufacturer’s instructions. Then,
align the microscope using the following
general alignment routine at the beginning
of every counting session and more often if
necessary.
6.6.1. Alignment
(1) Clean all optical surfaces. Even a small
amount of dirt can significantly degrade the
image.
(2) Rough focus the objective on a sample.
(3) Close down the field iris so that it is
visible in the field of view. Focus the image
of the iris with the condenser focus. Center
the image of the iris in the field of view.
(4) Install the phase telescope and focus on
the phase rings. Critically center the rings.
Misalignment of the rings results in astigmatism which will degrade the image.
(5) Place the phase-shift test slide on the
microscope stage and focus on the lines. The
analyst must see line set 3 and should see at
least parts of 4 and 5 but, not see line set 6
or 6. A microscope/microscopist combination
which does not pass this test may not be
used.
6.6.2. Counting Fibers
(1) Place the prepared sample slide on the
mechanical stage of the microscope. Position
the center of the wedge under the objective
lens and focus upon the sample.
(2) Start counting from one end of the
wedge and progress along a radial line to the
other end (count in either direction from perimeter to wedge tip). Select fields randomly, without looking into the eyepieces,
by slightly advancing the slide in one direction with the mechanical stage control.
(3) Continually scan over a range of focal
planes (generally the upper 10 to 15 μm of the
filter surface) with the fine focus control
during each field count. Spend at least 5 to
15 seconds per field.
(4) Most samples will contain asbestos fibers with fiber diameters less than 1 μm.
Look carefully for faint fiber images. The
small diameter fibers will be very hard to
see. However, they are an important contribution to the total count.
(5) Count only fibers equal to or longer
than 5 μm. Measure the length of curved fibers along the curve.
(6) Count fibers which have a length to
width ratio of 3:1 or greater.
(7) Count all the fibers in at least 20 fields.
Continue counting until either 100 fibers are
counted or 100 fields have been viewed;
whichever occurs first. Count all the fibers
in the final field.
(8) Fibers lying entirely within the boundary of the Walton-Beckett graticule field
shall receive a count of 1. Fibers crossing the
boundary once, having one end within the
circle shall receive a count of 1⁄2. Do not
count any fiber that crosses the graticule

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29 CFR Ch. XVII (7–1–16 Edition)

boundary more than once. Reject and do not
count any other fibers even though they may
be visible outside the graticule area. If a
fiber touches the circle, it is considered to
cross the line.
(9) Count bundles of fibers as one fiber unless individual fibers can be clearly identified and each individual fiber is clearly not
connected to another counted fiber. See Figure 1 for counting conventions.
(10) Record the number of fibers in each
field in a consistent way such that filter
non-uniformity can be assessed.
(11) Regularly check phase ring alignment.
(12) When an agglomerate (mass of material) covers more than 25% of the field of
view, reject the field and select another. Do
not include it in the number of fields counted.
(13) Perform a ‘‘blind recount’’ of 1 in every
10 filter wedges (slides). Re-label the slides
using a person other than the original
counter.

are quality assurance counts. The slide bank
shall be prepared using uniformly distributed
samples taken from the workload. Fiber densities should cover the entire range routinely
analyzed by the laboratory. These slides are
counted blind by all counters to establish an
original standard deviation. This historical
distribution is compared with the quality assurance counts. A counter must have 95% of
all quality control samples counted within
three standard deviations of the historical
mean. This count is then integrated into a
new historical mean and standard deviation
for the slide.
The analyses done by the counters to establish the slide bank may be used for an interim quality control program if the data are
treated in a proper statistical fashion.
7. Calculations
7.1. Calculate the estimated airborne asbestos fiber concentration on the filter sample
using the following formula:
where:
AC = Airborne fiber concentration

6.7. Fiber Identification
As previously mentioned in Section 1.3.,
PCM does not provide positive confirmation
of asbestos fibers. Alternate differential
counting techniques should be used if discrimination is desirable. Differential counting may include primary discrimination
based on morphology, polarized light analysis of fibers, or modification of PCM data
by Scanning Electron or Transmission Electron Microscopy.
A great deal of experience is required to
routinely and correctly perform differential
counting. It is discouraged unless it is legally necessary. Then, only if a fiber is obviously not asbestos should it be excluded from
the count. Further discussion of this technique can be found in reference 8.10.
If there is a question whether a fiber is asbestos or not, follow the rule:
‘‘WHEN IN DOUBT, COUNT.’’

AC =

1000 × FR × T × MFA

FB = Total number of fibers greater than 5
μm counted
FL = Total number of fields counted on the
filter
BFB = Total number of fibers greater than 5
μm counted in the blank
BFL = Total number of fields counted on the
blank
ECA = Effective collecting area of filter (385
mm2 nominal for a 25-mm filter.)
FR = Pump flow rate (L/min)
MFA = Microscope count field area (mm2).
This is 0.00785 mm2 for a Walton-Beckett
Graticule.
T = Sample collection time (min)
1,000 = Conversion of L to cc
NOTE: The collection area of a filter is seldom equal to 385 mm2. It is appropriate for
laboratories to routinely monitor the exact
diameter using an inside micrometer. The
collection area is calculated according to the
formula:
Area = π(d/2)2

6.8. Analytical Recommendations—Quality
Control System
6.8.1. All individuals performing asbestos
analysis must have taken the NIOSH course
for sampling and evaluating airborne asbestos or an equivalent course.
6.8.2. Each laboratory engaged in asbestos
counting shall set up a slide trading arrangement with at least two other laboratories in
order to compare performance and eliminate
inbreeding of error. The slide exchange occurs at least semiannually. The round robin
results shall be posted where all analysts can
view individual analyst’s results.
6.8.3. Each laboratory engaged in asbestos
counting shall participate in the Proficiency
Analytical Testing Program, the Asbestos
Analyst Registry or equivalent.
6.8.4. Each analyst shall select and count
prepared slides from a ‘‘slide bank’’. These

7.2. Short-cut Calculation
Since a given analyst always has the same
interpupillary distance, the number of fields
per filter for a particular analyst will remain
constant for a given size filter. The field size
for that analyst is constant (i.e. the analyst
is using an assigned microscope and is not
changing the reticle).
For example, if the exposed area of the filter is always 385 mm2 and the size of the field

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⎡⎛ FB ⎞ ⎛ BFB ⎞ ⎤
⎟ ⎥ × ECA
⎟ −⎜
⎢⎜
⎣⎝ FL ⎠ ⎝ BFL ⎠ ⎦

Occupational Safety and Health Admin., Labor
is always 0.00785 mm2, the number of fields
per filter will always be 49,000. In addition it
is necessary to convert liters of air to cc.
These three constants can then be combined
such that ECA/(1,000 × MFA) = 49. The previous equation simplifies to:

ple, an average of the results is to be reported unless any of the results can be rejected for cause.
8. References
8.1. Dreesen, W.C., et al, U.S. Public Health
Service: A Study of Asbestosis in the Asbestos
Textile Industry, (Public Health Bulletin No.
241), US Treasury Dept., Washington, DC,
1938.
8.2. Asbestos Research Council: The Measurement of Airborne Asbestos Dust by the Membrane Filter Method (Technical Note), Asbestos Research Council, Rockdale, Lancashire,
Great Britain, 1969.
8.3. Bayer, S.G., Zumwalde, R.D., Brown,
T.A., Equipment and Procedure for Mounting
Millipore Filters and Counting Asbestos Fibers
by Phase Contrast Microscopy, Bureau of Occupational Health, U.S. Dept. of Health, Education and Welfare, Cincinnati, OH, 1969.
8.4. NIOSH Manual of Analytical Methods,
2nd ed., Vol. 1 (DHEW/NIOSH Pub. No. 77–
157–A). National Institute for Occupational
Safety and Health, Cincinnati, OH, 1977. pp.
239–1-239–21.
8.5. Asbestos, Code of Federal Regulations
29 CFR 1910.1001. 1971.
8.6. Occupational Exposure to Asbestos,
Tremolite, Anthophyllite, and Actinolite. Final
Rule, FEDERAL REGISTER 51:119 (20 June 1986).
pp.22612–22790.
8.7. Asbestos, Tremolite, Anthophyllite, and
Actinolite, Code of Federal Regulations
1910.1001. 1988. pp 711–752.
8.8. Criteria for a Recommended Standard—
Occupational Exposure to Asbestos (DHEW/
NIOSH Pub. No. HSM 72–10267), National Institute for Occupational Safety and Health
NIOSH, Cincinnati,OH, 1972. pp. III–1–III–24.
8.9. Leidel, N.A., Bayer,S.G., Zumwalde,
R.D.,Busch, K.A., USPHS/NIOSH Membrane
Filter Method for Evaluating Airborne Asbestos
Fibers (DHEW/NIOSH Pub. No. 79–127). National Institute for Occupational Safety and
Health, Cincinnati, OH, 1979.
8.10. Dixon, W.C., Applications of Optical Microscopy in Analysis of Asbestos and Quartz,
Analytical Techniques in Occupational
Health Chemistry, edited by D.D. Dollberg
and A.W. Verstuyft. Wash. DC: American
Chemical Society, (ACS Symposium Series
120) 1980. pp. 13–41.

⎛ FB ⎞ ⎛ BFB ⎞
⎟ × 49
⎟ −⎜
⎜
⎝ FL ⎠ ⎝ BFL ⎠
FR × T

7.3. Recount Calculations
As mentioned in step 13 of Section 6.6.2., a
‘‘blind recount’’ of 10% of the slides is performed. In all cases, differences will be observed between the first and second counts of
the same filter wedge. Most of these differences will be due to chance alone, that is,
due to the random variability (precision) of
the count method. Statistical recount criteria enables one to decide whether observed
differences can be explained due to chance
alone or are probably due to systematic differences between analysts, microscopes, or
other biasing factors.
The following recount criterion is for a
pair of counts that estimate AC in fibers/cc.
The criterion is given at the type-I error
level. That is, there is 5% maximum risk
that we will reject a pair of counts for the
reason that one might be biased, when the
large observed difference is really due to
chance.
Reject a pair of counts if:

AC 2 − AC1 > 2.78

(

)

AC AVG × CVFB

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Where:
AC1 = lower estimated airborne fiber concentration
AC2 = higher estimated airborne fiber concentration
ACavg = average of the two concentration
estimates
CVFB = CV for the average of the two concentration estimates
If a pair of counts are rejected by this criterion then, recount the rest of the filters in
the submitted set. Apply the test and reject
any other pairs failing the test. Rejection
shall include a memo to the industrial hygienist stating that the sample failed a statistical test for homogeneity and the true air
concentration may be significantly different
than the reported value.

Quality Control
The OSHA asbestos regulations require
each laboratory to establish a quality control program. The following is presented as
an example of how the OSHA-SLTC constructed its internal CV curve as part of
meeting this requirement. Data is from 395
samples collected during OSHA compliance
inspections and analyzed from October 1980
through April 1986.

7.4. Reporting Results
Report results to the industrial hygienist
as fibers/cc. Use two significant figures. If
multiple analyses are performed on a sam-

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×

ER10AU94.001

AC =

§ 1910.1001

§ 1910.1001

29 CFR Ch. XVII (7–1–16 Edition)

Each sample was counted by 2 to 5 different counters independently of one another. The standard deviation and the CV
statistic was calculated for each sample.
This data was then plotted on a graph of CV
vs. fibers/mm2. A least squares regression
was performed using the following equation:
CV = antilog110[A(log10(x))2 + B(log10(x)) + C]
where:
x = the number of fibers/mm2
Application of least squares gave:
A = 0.182205
B = ¥0.973343
C = 0.327499
Using these values, the equation becomes:
[0.182205(log10
CV
=
antilog10
(x))2¥0.973343(log10 (x)) + 0.327499]

(5) Remove the graticule from the microscope and measure its actual grid length, AL
(mm). This can be accomplished by using a
mechanical stage fitted with verniers, or a
jeweler’s loupe with a direct reading scale.
(6) Let D = 100 μm. Calculate the circle diameter, dc (mm), for the Walton-Beckett
graticule and specify the diameter when
making a purchase:

dc =

PL

Example: If PL = 108 μm, AL = 2.93 mm and
D = 100 μm, then,

dc =

2.93 × 100
108

Sampling Pump Flow Rate Corrections

= 2.71mm

(7) Each eyepiece-objective-reticle combination on the microscope must be calibrated. Should any of the three be changed
(by zoom adjustment, disassembly, replacement, etc.), the combination must be recalibrated. Calibration may change if interpupillary distance is changed. Measure the field
diameter, D (acceptable range: 100±2 μm)
with a stage micrometer upon receipt of the
graticule from the manufacturer. Determine
the field area (mm2).
Field Area = D(D/2)2
If D = 100 μm = 0.1 mm, then
Field Area = D(0.1 mm/2)2 = 0.00785 mm2
The Graticule is available from: Graticules
Ltd., Morley Road, Tonbridge TN9 IRN,
Kent, England (Telephone 011–44–732–359061).
Also available from PTR Optics Ltd., 145
Newton Street, Waltham, MA 02154 [telephone (617) 891–6000] or McCrone Accessories
and Components, 2506 S. Michigan Ave., Chicago, IL 60616 [phone (312)-842–7100]. The
graticule is custom made for each microscope.

This correction is used if a difference
greater than 5% in ambient temperature and/
or pressure is noted between calibration and
sampling sites and the pump does not compensate for the differences.

⎛P ⎞ ⎛T ⎞
Q act = Q cal × ⎜ cal ⎟ × ⎜ act ⎟
⎝ Pact ⎠ ⎝ Tcal ⎠
Where:
Qact = actual flow rate
Qcal = calibrated flow rate (if a rotameter was
used, the rotameter value)
Pcal = uncorrected air pressure at calibration
Pact = uncorrected air pressure at sampling
site
Tact = temperature at sampling site (K)
Tcal = temperature at calibration (K)
Walton-Beckett Graticule
When ordering the Graticule for asbestos
counting, specify the exact disc diameter
needed to fit the ocular of the microscope
and the diameter (mm) of the circular counting area. Instructions for measuring the dimensions necessary are listed:
(1) Insert any available graticule into the
focusing eyepiece and focus so that the graticule lines are sharp and clear.
(2) Align the microscope.
(3) Place a stage micrometer on the microscope object stage and focus the microscope
on the graduated lines.
(4) Measure the magnified grid length, PL
(μm), using the stage micrometer.

COUNTS FOR THE FIBERS IN THE FIGURE
Structure No.

Count

1 to 6 .........
................
................
................
................
................
................

⁄
0
2
0
0
1⁄2
12

Single fibers all contained within
the circle.
Fiber crosses circle once.
Fiber too short.
Two crossing fibers.
Fiber outside graticule.
Fiber crosses graticule twice.
Although split, fiber only crosses
once.

ER10AU94.004

ER10AU94.005

7
8
9
10
11
12

Explanation
1

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AL × D

Occupational Safety and Health Admin., Labor

APPENDIX C TO § 1910.1001 [RESERVED]

gram. Part 1 of the appendix contains the
Initial Medical Questionnaire, which must be
obtained for all new hires who will be covered by the medical surveillance requirements. Part 2 includes the abbreviated Periodical Medical Questionnaire, which must be
administered to all employees who are provided periodic medical examinations under
the medical surveillance provisions of the
standard.

APPENDIX D TO § 1910.1001—MEDICAL
QUESTIONNAIRES; MANDATORY
This mandatory appendix contains the
medical questionnaires that must be administered to all employees who are exposed to
asbestos above the permissible exposure
limit, and who will therefore be included in
their employer’s medical surveillance pro-

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§ 1910.1001

29 CFR Ch. XVII (7–1–16 Edition)

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§ 1910.1001

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§ 1910.1001

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29 CFR Ch. XVII (7–1–16 Edition)

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§ 1910.1001

Occupational Safety and Health Admin., Labor

APPENDIX F TO § 1910.1001—WORK PRACTICES
AND ENGINEERING CONTROLS FOR AUTOMOTIVE BRAKE AND CLUTCH INSPECTION, DISASSEMBLY, REPAIR AND ASSEMBLY—MANDA-

APPENDIX E TO § 1910.1001—INTERPRETATION
AND CLASSIFICATION OF CHEST ROENTGENOGRAMS—MANDATORY
(a) Chest roentgenograms shall be interpreted and classified in accordance with a
professionally accepted Classification system and recorded on an interpretation form
following the format of the CDC/NIOSH (M)
2.8 form. As a minimum, the content within
the bold lines of this form (items 1 though 4)
shall be included. This form is not to be submitted to NIOSH.
(b) Roentgenograms shall be interpreted
and classified only by a B-reader, a board eligible/certified radiologist, or an experienced
physician
with
known
expertise
in
pneumoconioses.
(c) All interpreters, whenever interpreting
chest roentgenograms made under this section, shall have immediately available for
reference a complete set of the ILO-U/C
International Classification of Radiographs
for Pneumoconioses, 1980.

TORY

This mandatory appendix specifies engineering controls and work practices that
must be implemented by the employer during automotive brake and clutch inspection,
disassembly, repair, and assembly operations. Proper use of these engineering controls and work practices by trained employees will reduce employees’ asbestos exposure
below the permissible exposure level during
clutch and brake inspection, disassembly, repair, and assembly operations. The employer
shall institute engineering controls and
work practices using either the method set
forth in paragraph [A] or paragraph [B] of
this appendix, or any other method which
the employer can demonstrate to be equivalent in terms of reducing employee exposure
to asbestos as defined and which meets the
requirements described in paragraph [C] of

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§ 1910.1001

§ 1910.1001

29 CFR Ch. XVII (7–1–16 Edition)

this appendix, for those facilities in which no
more than 5 pairs of brakes or 5 clutches are
inspected, disassembled, reassembled and/or
repaired per week, the method set forth in
paragraph [D] of this appendix may be used:

(5) The brake support plate, brake shoes
and brake components used to attach the
brake shoes shall be thoroughly washed before removing the old shoes.
(6) In systems using filters, the filters,
when full, shall be first wetted with a fine
mist of water, then removed and placed immediately in an impermeable container, labeled according to paragraph (j)(4) of this
section and disposed of according to paragraph (k) of this section.
(7) Any spills of asbestos-containing aqueous solution or any asbestos-containing
waste material shall be cleaned up immediately and disposed of according to paragraph (k) of this section.
(8) The use of dry brushing during low pressure/wet cleaning operations is prohibited.

[A] Negative Pressure Enclosure/HEPA Vacuum
System Method
(1) The brake and clutch inspection, disassembly, repair, and assembly operations
shall be enclosed to cover and contain the
clutch or brake assembly and to prevent the
release of asbestos fibers into the worker’s
breathing zone.
(2) The enclosure shall be sealed tightly
and thoroughly inspected for leaks before
work begins on brake and clutch inspection,
disassembly, repair, and assembly.
(3) The enclosure shall be such that the
worker can clearly see the operation and
shall provide impermeable sleeves through
which the worker can handle the brake and
clutch inspection, disassembly, repair and
assembly. The integrity of the sleeves and
ports shall be examined before work begins.
(4) A HEPA-filtered vacuum shall be employed to maintain the enclosure under negative pressure throughout the operation.
Compressed-air may be used to remove asbestos fibers or particles from the enclosure.
(5) The HEPA vacuum shall be used first to
loosen the asbestos containing residue from
the brake and clutch parts and then to evacuate the loosened asbestos containing material from the enclosure and capture the material in the vacuum filter.
(6) The vacuum’s filter, when full, shall be
first wetted with a fine mist of water, then
removed and placed immediately in an impermeable container, labeled according to
paragraph (j)(5) of this section and disposed
of according to paragraph (k) of this section.
(7) Any spills or releases of asbestos containing waste material from inside of the enclosure or vacuum hose or vacuum filter
shall be immediately cleaned up and disposed of according to paragraph (k) of this
section.

[C] Equivalent Methods
An equivalent method is one which has sufficient written detail so that it can be reproduced and has been demonstrated that the
exposures resulting from the equivalent
method are equal to or less than the exposures which would result from the use of the
method described in paragraph [A] of this appendix. For purposes of making this comparison, the employer shall assume that exposures resulting from the use of the method
described in paragraph [A] of this appendix
shall not exceed 0.016 f/cc, as measured by
the OSHA reference method and as averaged
over at least 18 personal samples.
[D] Wet Method.
(1) A spray bottle, hose nozzle, or other implement capable of delivering a fine mist of
water or amended water or other delivery
system capable of delivering water at low
pressure, shall be used to first thoroughly
wet the brake and clutch parts. Brake and
clutch components shall then be wiped clean
with a cloth.
(2) The cloth shall be placed in an impermeable container, labelled according to paragraph (j)(4) of this section and then disposed
of according to paragraph (k) of this section,
or the cloth shall be laundered in a way to
prevent the release of asbestos fibers in excess of 0.1 fiber per cubic centimeter of air.
(3) Any spills of solvent or any asbestos
containing waste material shall be cleaned
up immediately according to paragraph (k)
of this section.
(4) The use of dry brushing during the wet
method operations is prohibited.

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[B] Low Pressure/Wet Cleaning Method
(1) A catch basin shall be placed under the
brake assembly, positioned to avoid splashes
and spills.
(2) The reservoir shall contain water containing an organic solvent or wetting agent.
The flow of liquid shall be controlled such
that the brake assembly is gently flooded to
prevent the asbestos-containing brake dust
from becoming airborne.
(3) The aqueous solution shall be allowed
to flow between the brake drum and brake
support before the drum is removed.
(4) After removing the brake drum, the
wheel hub and back of the brake assembly
shall be thoroughly wetted to suppress dust.

APPENDIX G TO § 1910.1001—SUBSTANCE TECHNICAL INFORMATION FOR ASBESTOS—NONMANDATORY
I. Substance Identification
A. Substance: ‘‘Asbestos’’ is the name of a
class of magnesium-silicate minerals that

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Occupational Safety and Health Admin., Labor
occur in fibrous form. Minerals that are included in this group are chrysotile, crocidolite,
amosite,
tremolite
asbestos,
anthophyllite asbestos, and actinolite asbestos.
B. Asbestos is used in the manufacture of
heat-resistant clothing, automative brake
and clutch linings, and a variety of building
materials including floor tiles, roofing felts,
ceiling tiles, asbestos-cement pipe and sheet,
and fire-resistant drywall. Asbestos is also
present in pipe and boiler insulation materials, and in sprayed-on materials located on
beams, in crawlspaces, and between walls.
C. The potential for a product containing
asbestos to release breatheable fibers depends on its degree of friability. Friable
means that the material can be crumbled
with hand pressure and is therefore likely to
emit fibers. The fibrous or fluffy sprayed-on
materials used for fireproofing, insulation,
or sound proofing are considered to be friable, and they readily release airborne fibers
if disturbed. Materials such as vinyl-asbestos
floor tile or roofing felts are considered nonfriable and generally do not emit airborne fibers unless subjected to sanding or sawing
operations. Asbestos-cement pipe or sheet
can emit airborne fibers if the materials are
cut or sawed, or if they are broken during
demolition operations.
D. Permissible exposure: Exposure to airborne asbestos fibers may not exceed 0.2 fibers per cubic centimeter of air (0.1 f/cc)
averaged over the 8-hour workday.

§ 1910.1001

centrations do not exceed 2 f/cc; otherwise,
air-supplied, positive-pressure, full facepiece
respirators must be used. Disposable respirators or dust masks are not permitted to
be used for asbestos work. For effective protection, respirators must fit your face and
head snugly. Your employer is required to
conduct fit tests when you are first assigned
a respirator and every 6 months thereafter.
Respirators should not be loosened or removed in work situations where their use is
required.
B. Protective clothing: You are required to
wear protective clothing in work areas where
asbestos fiber concentrations exceed the permissible exposure limit.
IV. Disposal Procedures and Cleanup
A. Wastes that are generated by processes
where asbestos is present include:
1. Empty asbestos shipping containers.
2. Process wastes such as cuttings, trimmings, or reject material.
3. Housekeeping waste from sweeping or
vacuuming.
4. Asbestos fireproofing or insulating material that is removed from buildings.
5. Building products that contain asbestos
removed during building renovation or demolition.
6. Contaminated disposable protective
clothing.
B. Empty shipping bags can be flattened
under exhaust hoods and packed into airtight containers for disposal. Empty shipping drums are difficult to clean and should
be sealed.
C. Vacuum bags or disposable paper filters
should not be cleaned, but should be sprayed
with a fine water mist and placed into a labeled waste container.
D. Process waste and housekeeping waste
should be wetted with water or a mixture of
water and surfactant prior to packaging in
disposable containers.
E. Material containing asbestos that is removed from buildings must be disposed of in
leak-tight 6-mil thick plastic bags, plasticlined cardboard containers, or plastic-lined
metal containers. These wastes, which are
removed while wet, should be sealed in containers before they dry out to minimize the
release of asbestos fibers during handling.

II. Health Hazard Data
A. Asbestos can cause disabling respiratory
disease and various types of cancers if the fibers are inhaled. Inhaling or ingesting fibers
from contaminated clothing or skin can also
result in these diseases. The symptoms of
these diseases generally do not appear for 20
or more years after initial exposure.
B. Exposure to asbestos has been shown to
cause lung cancer, mesothelioma, and cancer
of the stomach and colon. Mesothelioma is a
rare cancer of the thin membrane lining of
the chest and abdomen. Symptoms of mesothelioma include shortness of breath, pain in
the walls of the chest, and/or abdominal
pain.

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III. Respirators and Protective Clothing
V. Access to Information

A. Respirators: You are required to wear a
respirator when performing tasks that result
in asbestos exposure that exceeds the permissible exposure limit (PEL) of 0.1 f/cc.
These conditions can occur while your employer is in the process of installing engineering controls to reduce asbestos exposure,
or where engineering controls are not feasible to reduce asbestos exposure. Air-purifying respirators equipped with a high-efficiency particulate air (HEPA) filter can be
used where airborne asbestos fiber con-

A. Each year, your employer is required to
inform you of the information contained in
this standard and appendices for asbestos. In
addition, your employer must instruct you
in the proper work practices for handling
materials containing asbestos, and the correct use of protective equipment.
B. Your employer is required to determine
whether you are being exposed to asbestos.
You or your representative has the right to
observe employee measurements and to

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§ 1910.1001

29 CFR Ch. XVII (7–1–16 Edition)

record the results obtained. Your employer
is required to inform you of your exposure,
and, if you are exposed above the permissible
limit, he or she is required to inform you of
the actions that are being taken to reduce
your exposure to within the permissible
limit.
C. Your employer is required to keep
records of your exposures and medical examinations. These exposure records must be
kept for at least thirty (30) years. Medical
records must be kept for the period of your
employment plus thirty (30) years.
D. Your employer is required to release
your exposure and medical records to your
physician or designated representative upon
your written request.

shortness of breath, pain in the walls of the
chest, or abdominal pain. Mesothelioma has
a much longer latency period compared with
lung cancer (40 years versus 15–20 years), and
mesothelioma is therefore more likely to be
found among workers who were first exposed
to asbestos at an early age. Mesothelioma is
always fatal.
Asbestosis is pulmonary fibrosis caused by
the accumulation of asbestos fibers in the
lungs. Symptoms include shortness of
breath, coughing, fatigue, and vague feelings
of sickness. When the fibrosis worsens, shortness of breath occurs even at rest. The diagnosis of asbestosis is based on a history of
exposure to asbestos, the presence of characteristic radiologic changes, end-inspiratory crackles (rales), and other clinical features of fibrosing lung disease. Pleural
plaques and thickening are observed on Xrays taken during the early stages of the disease. Asbestosis is often a progressive disease even in the absence of continued exposure, although this appears to be a highly individualized characteristic. In severe cases,
death may be caused by respiratory or cardiac failure.

APPENDIX H TO § 1910.1001—MEDICAL SURVEILLANCE GUIDELINES FOR ASBESTOS NON-MANDATORY

I. Route of Entry Inhalation, Ingestion
II. Toxicology
Clinical evidence of the adverse effects associated with exposure to asbestos is present
in the form of several well-conducted epidemiological studies of occupationally exposed
workers, family contacts of workers, and
persons living near asbestos mines. These
studies have shown a definite association between exposure to asbestos and an increased
incidence of lung cancer, pleural and peritoneal mesothelioma, gastrointestinal cancer, and asbestosis. The latter is a disabling
fibrotic lung disease that is caused only by
exposure to asbestos. Exposure to asbestos
has also been associated with an increased
incidence of esophageal, kidney, laryngeal,
pharyngeal, and buccal cavity cancers. As
with other known chronic occupational diseases, disease associated with asbestos generally appears about 20 years following the
first occurrence of exposure: There are no
known acute effects associated with exposure to asbestos.
Epidemiological studies indicate that the
risk of lung cancer among exposed workers
who smoke cigarettes is greatly increased
over the risk of lung cancer among non-exposed smokers or exposed nonsmokers. These
studies suggest that cessation of smoking
will reduce the risk of lung cancer for a person exposed to asbestos but will not reduce it
to the same level of risk as that existing for
an exposed worker who has never smoked.

IV. Surveillance and Preventive
Considerations
As noted above, exposure to asbestos has
been linked to an increased risk of lung cancer, mesothelioma, gastrointestinal cancer,
and asbestosis among occupationally exposed workers. Adequate screening tests to
determine an employee’s potential for developing serious chronic diseases, such as cancer, from exposure to asbestos do not presently exist. However, some tests, particularly chest X-rays and pulmonary function
tests, may indicate that an employee has
been overexposed to asbestos increasing his
or her risk of developing exposure-related
chronic diseases. It is important for the physician to become familiar with the operating
conditions in which occupational exposure to
asbestos is likely to occur. This is particularly important in evaluating medical and
work histories and in conducting physical
examinations. When an active employee has
been identified as having been overexposed
to asbestos, measures taken by the employer
to eliminate or mitigate further exposure
should also lower the risk of serious longterm consequences.
The employer is required to institute a
medical surveillance program for all employees who are or will be exposed to asbestos at
or above the permissible exposure limit (0.1
fiber per cubic centimeter of air). All examinations and procedures must be performed
by or under the supervision of a licensed
physician, at a reasonable time and place,
and at no cost to the employee.
Although broad latitude is given to the
physician in prescribing specific tests to be

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III. Signs and Symptoms of ExposureRelated Disease
The signs and symptoms of lung cancer or
gastrointestinal cancer induced by exposure
to asbestos are not unique, except that a
chest X-ray of an exposed patient with lung
cancer may show pleural plaques, pleural
calcification, or pleural fibrosis. Symptoms
characteristic of mesothelioma include

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Occupational Safety and Health Admin., Labor

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included in the medical surveillance program, OSHA requires inclusion of the following elements in the routine examination:
(i) Medical and work histories with special
emphasis directed to symptoms of the respiratory system, cardiovascular system, and
digestive tract.
(ii) Completion of the respiratory disease
questionnaire contained in appendix D.
(iii) A physical examination including a
chest roentgenogram and pulmonary function test that includes measurement of the
employee’s forced vital capacity (FVC) and
forced expiratory volume at one second
(FEV1).
(iv) Any laboratory or other test that the
examining physician deems by sound medical practice to be necessary.
The employer is required to make the prescribed tests available at least annually to
those employees covered; more often than
specified if recommended by the examining
physician; and upon termination of employment.
The employer is required to provide the
physician with the following information: A
copy of this standard and appendices; a description of the mployee’s duties as they relate to asbestos exposure; the employee’s
representative level of exposure to asbestos;
a description of any personal protective and
respiratory equipment used; and information
from previous medical examinations of the
affected employee that is not otherwise
available to the physician. Making this information available to the physician will aid
in the evaluation of the employee’s health in
relation to assigned duties and fitness to
wear personal protective equipment, if required.
The employer is required to obtain a written opinion from the examining physician
containing the results of the medical examination; the physician’s opinion as to whether the employee has any detected medical
conditions that would place the employee at
an increased risk of exposure-related disease;
any recommended limitations on the employee or on the use of personal protective
equipment; and a statement that the employee has been informed by the physician of
the results of the medical examination and
of any medical conditions related to asbestos
exposure that require further explanation or
treatment. This written opinion must not reveal specific findings or diagnoses unrelated
to exposure to asbestos, and a copy of the
opinion must be provided to the affected employee.

§ 1910.1001

1. The National Cancer Institute operates a
toll-free Cancer Information Service (CIS)
with trained personnel to help you. Call 1–
800–4–CANCER* to reach the CIS office serving your area, or write: Office of Cancer
Communications, National Cancer Institute,
National Institutes of Health, Building 31,
Room 10A24, Bethesda, Maryland 20892.
2. American Cancer Society, 3340 Peachtree
Road, NE., Atlanta, Georgia 30062, (404) 320–
3333.
The American Cancer Society (ACS) is a
voluntary organization composed of 58 divisions and 3,100 local units. Through ‘‘The
Great American Smokeout’’ in November,
the annual Cancer Crusade in April, and numerous educational materials, ACS helps
people learn about the health hazards of
smoking and become successful ex-smokers.
3. American Heart Association, 7320 Greenville Avenue, Dallas, Texas 75231, (214) 750–
5300.
The American Heart Association (AHA) is
a voluntary organization with 130,000 members (physicians, scientists, and laypersons)
in 55 state and regional groups. AHA produces a variety of publications and audiovisual materials about the effects of smoking on the heart. AHA also has developed a
guidebook for incorporating a weight-control
component into smoking cessation programs.
4. American Lung Association, 1740 Broadway, New York, New York 10019, (212) 245–
8000.
A voluntary organization of 7,500 members
(physicians, nurses, and laypersons), the
American Lung Association (ALA) conducts
numerous public information programs
about the health effect of smoking. ALA has
59 state and 85 local units. The organization
actively supports legislation and information campaigns for non-smokers’ rights and
provides help for smokers who want to quit,
for example, through ‘‘Freedom From Smoking,’’ a self-help smoking cessation program.
5. Office on Smoking and Health, U.S. Department of Health and, Human Services,
5600 Fishers Lane, Park Building, Room 110,
Rockville, Maryland 20857.
The Office on Smoking and Health (OSH) is
the Department of Health and Human Services’ lead agency in smoking control. OSH
has sponsored distribution of publications on
smoking-realted topics, such as free flyers on
relapse after initial quitting, helping a
friend or family member quit smoking, the
health hazards of smoking, and the effects of
parental smoking on teenagers.
*In Hawaii, on Oahu call 524–1234 (call collect from neighboring islands),
Spanish-speaking staff members are available during daytime hours to callers from
the following areas: California, Florida,
Georgia, Illinois, New Jersey (area code 210),
New York, and Texas. Consult your local

APPENDIX I TO § 1910.1001—SMOKING CESSATION
PROGRAM INFORMATION FOR ASBESTOS—
NON-MANDATORY
The following organizations provide smoking cessation information and program material.

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§ 1910.1001

29 CFR Ch. XVII (7–1–16 Edition)
Aspect Ratio: The ratio of the length of a
fiber to its diameter usually defined as
‘‘length : width’’, e.g. 3:1.
Brucite: A sheet mineral with the composition Mg(OH)2.
Central Stop Dispersion Staining (microscope):
This is a dark field microscope technique
that images particles using only light refracted by the particle, excluding light that
travels through the particle unrefracted.
This is usually accomplished with a McCrone
objective or other arrangement which places
a circular stop with apparent aperture equal
to the objective aperture in the back focal
plane of the microscope.
Cleavage Fragments: Mineral particles
formed by the comminution of minerals, especially those characterized by relatively
parallel sides and moderate aspect ratio.
Differential Counting: The term applied to
the practice of excluding certain kinds of fibers from a phase contrast asbestos count
because they are not asbestos.
Fiber: A particle longer than or equal to 5
μm with a length to width ratio greater than
or equal to 3:1. This may include cleavage
fragments. (see section 3.5 of this appendix).
Phase Contrast: Contrast obtained in the
microscope by causing light scattered by
small particles to destructively interfere
with unscattered light, thereby enhancing
the visibility of very small particles and particles with very low intrinsic contrast.
Phase Contrast Microscope: A microscope
configured with a phase mask pair to create
phase contrast. The technique which uses
this is called Phase Contrast Microscopy
(PCM).
Phase-Polar Analysis: This is the use of polarized light in a phase contrast microscope.
It is used to see the same size fibers that are
visible in air filter analysis. Although fibers
finer than 1 μm are visible, analysis of these
is inferred from analysis of larger bundles
that are usually present.
Phase-Polar Microscope: The phase-polar
microscope is a phase contrast microscope
which has an analyzer, a polarizer, a first
order red plate and a rotating phase condenser all in place so that the polarized light
image is enhanced by phase contrast.
Sealing Encapsulant: This is a product
which can be applied, preferably by spraying,
onto an asbestos surface which will seal the
surface so that fibers cannot be released.
Serpentine: A mineral family consisting of
minerals with the general composition
Mg3(Si2O5(OH)4 having the magnesium in
brucite layer over a silicate layer. Minerals
important in asbestos analysis included in
this
family
are
chrysotile,
lizardite,
antigorite.

telephone directory for listings of local chapters.
APPENDIX J TO § 1910.1001—POLARIZED LIGHT
MICROSCOPY OF ASBESTOS—NON-MANDATORY
Method number: ID–191
Matrix: Bulk
Collection Procedure
Collect approximately 1 to 2 grams of each
type of material and place into separate 20
mL scintillation vials.
Analytical Procedure
A portion of each separate phase is analyzed by gross examination, phase-polar examination, and central stop dispersion microscopy.
Commercial manufacturers and products
mentioned in this method are for descriptive
use only and do not constitute endorsements
by USDOL-OSHA. Similar products from
other sources may be substituted.

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1. Introduction
This method describes the collection and
analysis of asbestos bulk materials by light
microscopy techniques including phasepolar illumination and central-stop dispersion microscopy. Some terms unique to asbestos analysis are defined below:
Amphibole: A family of minerals whose
crystals are formed by long, thin units which
have two thin ribbons of double chain silicate with a brucite ribbon in between. The
shape of each unit is similar to an ‘‘I beam’’.
Minerals important in asbestos analysis include cummingtonite-grunerite, crocidolite,
tremolite-actinolite and anthophyllite.
Asbestos: A term for naturally occurring fibrous minerals. Asbestos includes chrysotile,
cummingtonite-grunerite asbestos (amosite),
anthophyllite asbestos, tremolite asbestos,
crocidolite, actinolite asbestos and any of
these minerals which have been chemically
treated or altered. The precise chemical formulation of each species varies with the location from which it was mined. Nominal
compositions are listed:
Chrysotile ..........
Mg3 Si2 O5(OH)4
Crocidolite
(Riebeckite asbestos) .............
Na2 Fe32 + Fe23 + Si8
O22(OH)2
CummingtoniteGrunerite asbestos
(Amosite) ........
(Mg,Fe)7 Si8 O22(OH)2
Tremolite-Actinolite asbestos ..
Ca2(Mg,Fe)5 Si8 O22(OH)2
Anthophyllite asbestos ..............
(Mg,Fe)7 Si8 O22(OH)2

1.1. History
Light microscopy has been used for well
over 100 years for the determination of mineral species. This analysis is carried out

Asbestos Fiber: A fiber of asbestos meeting
the criteria for a fiber. (See section 3.5.)

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Occupational Safety and Health Admin., Labor
using specialized polarizing microscopes as
well as bright field microscopes. The identification of minerals is an on-going process
with many new minerals described each
year. The first recorded use of asbestos was
in Finland about 2500 B.C. where the material was used in the mud wattle for the wooden huts the people lived in as well as
strengthening for pottery. Adverse health aspects of the mineral were noted nearly 2000
years ago when Pliny the Younger wrote
about the poor health of slaves in the asbestos mines. Although known to be injurious
for centuries, the first modern references to
its toxicity were by the British Labor
Inspectorate when it banned asbestos dust
from the workplace in 1898. Asbestosis cases
were described in the literature after the
turn of the century. Cancer was first suspected in the mid 1930’s and a causal link to
mesothelioma was made in 1965. Because of
the public concern for worker and public
safety with the use of this material, several
different types of analysis were applied to
the determination of asbestos content. Light
microscopy requires a great deal of experience and craft. Attempts were made to apply
less subjective methods to the analysis. Xray diffraction was partially successful in
determining the mineral types but was unable to separate out the fibrous portions
from the non-fibrous portions. Also, the minimum detection limit for asbestos analysis
by X-ray diffraction (XRD) is about 1%. Differential Thermal Analysis (DTA) was no
more successful. These provide useful corroborating information when the presence of
asbestos has been shown by microscopy;
however, neither can determine the difference between fibrous and non-fibrous minerals when both habits are present. The same
is true of Infrared Absorption (IR).
When electron microscopy was applied to
asbestos analysis, hundreds of fibers were
discovered present too small to be visible in
any light microscope. There are two different types of electron microscope used for
asbestos analysis: Scanning Electron Microscope (SEM) and Transmission Electron Microscope (TEM). Scanning Electron Microscopy is useful in identifying minerals. The
SEM can provide two of the three pieces of
information required to identify fibers by
electron microscopy: morphology and chemistry. The third is structure as determined
by Selected Area Electron Diffraction—
SAED which is performed in the TEM. Although the resolution of the SEM is sufficient for very fine fibers to be seen, accuracy
of chemical analysis that can be performed
on the fibers varies with fiber diameter in fibers of less than 0.2 μm diameter. The TEM
is a powerful tool to identify fibers too small
to be resolved by light microscopy and
should be used in conjunction with this
method when necessary. The TEM can provide all three pieces of information required

§ 1910.1001

for fiber identification. Most fibers thicker
than 1 μm can adequately be defined in the
light microscope. The light microscope remains as the best instrument for the determination of mineral type. This is because
the minerals under investigation were first
described analytically with the light microscope. It is inexpensive and gives positive
identification for most samples analyzed.
Further, when optical techniques are inadequate, there is ample indication that alternative techniques should be used for complete identification of the sample.
1.2. Principle
Minerals consist of atoms that may be arranged in random order or in a regular arrangement. Amorphous materials have
atoms in random order while crystalline materials have long range order. Many materials are transparent to light, at least for
small particles or for thin sections. The
properties of these materials can be investigated by the effect that the material has
on light passing through it. The six asbestos
minerals are all crystalline with particular
properties that have been identified and cataloged. These six minerals are anisotropic.
They have a regular array of atoms, but the
arrangement is not the same in all directions. Each major direction of the crystal
presents a different regularity. Light photons travelling in each of these main directions will encounter different electrical
neighborhoods, affecting the path and time
of travel. The techniques outlined in this
method use the fact that light traveling
through fibers or crystals in different directions will behave differently, but predictably. The behavior of the light as it travels
through a crystal can be measured and compared with known or determined values to
identify the mineral species. Usually, Polarized Light Microscopy (PLM) is performed
with strain-free objectives on a bright-field
microscope platform. This would limit the
resolution of the microscope to about 0.4 μm.
Because OSHA requires the counting and
identification of fibers visible in phase contrast, the phase contrast platform is used to
visualize the fibers with the polarizing elements added into the light path. Polarized
light methods cannot identify fibers finer
than about 1 μm in diameter even though
they are visible. The finest fibers are usually
identified by inference from the presence of
larger, identifiable fiber bundles. When fibers
are present, but not identifiable by light microscopy, use either SEM or TEM to determine the fiber identity.
1.3. Advantages and Disadvantages
The advantages of light microcopy are:
(a) Basic identification of the materials
was first performed by light microscopy and
gross analysis. This provides a large base of

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§ 1910.1001

29 CFR Ch. XVII (7–1–16 Edition)

published information against which to
check analysis and analytical technique.
(b) The analysis is specific to fibers. The
minerals present can exist in asbestiform, fibrous, prismatic, or massive varieties all at
the same time. Therefore, bulk methods of
analysis such as X-ray diffraction, IR analysis, DTA, etc. are inappropriate where the
material is not known to be fibrous.
(c) The analysis is quick, requires little
preparation time, and can be performed onsite if a suitably equipped microscope is
available.
The disadvantages are:
(a) Even using phase-polar illumination,
not all the fibers present may be seen. This
is a problem for very low asbestos concentrations where agglomerations or large bundles
of fibers may not be present to allow identification by inference.
(b) The method requires a great degree of
sophistication
on
the
part
of
the
microscopist. An analyst is only as useful as
his mental catalog of images. Therefore, a
microscopist’s accuracy is enhanced by experience. The mineralogical training of the analyst is very important. It is the basis on
which subjective decisions are made.
(c) The method uses only a tiny amount of
material for analysis. This may lead to sampling bias and false results (high or low).
This is especially true if the sample is severely inhomogeneous.
(d) Fibers may be bound in a matrix and
not distinguishable as fibers so identification cannot be made.

amount is usually more than a few percent.
An analyst’s results can be ‘‘calibrated’’
against the known amounts added by the
manufacturer. For geological samples, the
degree of homogeneity affects the precision.
1.4.3. The performance of the method is analyst dependent. The analyst must choose
carefully and not necessarily randomly the
portions for analysis to assure that detection
of asbestos occurs when it is present. For
this reason, the analyst must have adequate
training in sample preparation, and experience in the location and identification of asbestos in samples. This is usually accomplished through substantial on-the-job training as well as formal education in mineralogy and microscopy.
1.5. Interferences
Any material which is long, thin, and
small enough to be viewed under the microscope can be considered an interference for
asbestos. There are literally hundreds of
interferences in workplaces. The techniques
described in this method are normally sufficient to eliminate the interferences. An analyst’s success in eliminating the interferences depends on proper training.
Asbestos minerals belong to two mineral
families: the serpentines and the amphiboles.
In the serpentine family, the only common
fibrous mineral is chrysotile. Occasionally,
the mineral antigorite occurs in a fibril
habit with morphology similar to the
amphiboles. The amphibole minerals consist
of a score of different minerals of which only
five are regulated by federal standard:
amosite, crocidolite, anthophyllite asbestos,
tremolite asbestos and actinolite asbestos.
These are the only amphibole minerals that
have been commercially exploited for their
fibrous properties; however, the rest can and
do occur occasionally in asbestiform habit.
In addition to the related mineral interferences, other minerals common in building
material may present a problem for some
microscopists: gypsum, anhydrite, brucite,
quartz fibers, talc fibers or ribbons, wollastonite, perlite, attapulgite, etc. Other fibrous materials commonly present in workplaces are: fiberglass, mineral wool, ceramic
wool, refractory ceramic fibers, kevlar,
nomex, synthetic fibers, graphite or carbon
fibers, cellulose (paper or wood) fibers, metal
fibers, etc.
Matrix embedding material can sometimes
be a negative interference. The analyst may
not be able to easily extract the fibers from
the matrix in order to use the method.
Where possible, remove the matrix before
the analysis, taking careful note of the loss
of weight. Some common matrix materials
are: vinyl, rubber, tar, paint, plant fiber, cement, and epoxy. A further negative interference is that the asbestos fibers themselves
may be either too small to be seen in Phase
contrast Microscopy (PCM) or of a very low

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1.4. Method Performance
1.4.1. This method can be used for determination of asbestos content from 0 to 100%
asbestos. The detection limit has not been
adequately determined, although for selected
samples, the limit is very low, depending on
the number of particles examined. For mostly homogeneous, finely divided samples, with
no difficult fibrous interferences, the detection limit is below 1%. For inhomogeneous
samples (most samples), the detection limit
remains undefined. NIST has conducted proficiency testing of laboratories on a national
scale. Although each round is reported statistically with an average, control limits,
etc., the results indicate a difficulty in establishing precision especially in the low
concentration range. It is suspected that
there is significant bias in the low range especially near 1%. EPA tried to remedy this
by requiring a mandatory point counting
scheme for samples less than 10%. The point
counting procedure is tedious, and may introduce significant biases of its own. It has
not been incorporated into this method.
1.4.2. The precision and accuracy of the
quantitation tests performed in this method
are unknown. Concentrations are easier to
determine in commercial products where asbestos was deliberately added because the

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Occupational Safety and Health Admin., Labor

2. Sampling Procedure

fibrous quality, having the appearance of
plant fibers. The analyst’s ability to deal
with these materials increases with experience.

2.1. Equipment for Sampling
(a)
(b)
(c)
(d)

1.6. Uses and Occupational Exposure
Asbestos is ubiquitous in the environment.
More than 40% of the land area of the United
States is composed of minerals which may
contain asbestos. Fortunately, the actual
formation of great amounts of asbestos is
relatively rare. Nonetheless, there are locations in which environmental exposure can
be severe such as in the Serpentine Hills of
California.
There are thousands of uses for asbestos in
industry and the home. Asbestos abatement
workers are the most current segment of the
population to have occupational exposure to
great amounts of asbestos. If the material is
undisturbed, there is no exposure. Exposure
occurs when the asbestos-containing material is abraded or otherwise disturbed during
maintenance operations or some other activity. Approximately 95% of the asbestos in
place in the United States is chrysotile.
Amosite and crocidolite make up nearly
all
the
difference.
Tremolite
and
anthophyllite make up a very small percentage. Tremolite is found in extremely small
amounts in certain chrysotile deposits. Actinolite exposure is probably greatest from
environmental sources, but has been identified in vermiculite containing, sprayed-on
insulating materials which may have been
certified as asbestos-free.

Tube or cork borer sampling device
Knife
20 mL scintillation vial or similar vial
Sealing encapsulant
2.2. Safety Precautions

Asbestos is a known carcinogen. Take care
when sampling. While in an asbestos-containing atmosphere, a properly selected and
fit-tested respirator should be worn. Take
samples in a manner to cause the least
amount of dust. Follow these general guidelines:
(a) Do not make unnecessary dust.
(b) Take only a small amount (1 to 2 g).
(c) Tightly close the sample container.
(d) Use encapsulant to seal the spot where
the sample was taken, if necessary.
2.3. Sampling Procedure
Samples of any suspect material should be
taken from an inconspicuous place. Where
the material is to remain, seal the sampling
wound with an encapsulant to eliminate the
potential for exposure from the sample site.
Microscopy requires only a few milligrams of
material. The amount that will fill a 20 mL
scintillation vial is more than adequate. Be
sure to collect samples from all layers and
phases of material. If possible, make separate samples of each different phase of the
material. This will aid in determining the
actual hazard. DO NOT USE ENVELOPES,
PLASTIC OR PAPER BAGS OF ANY KIND TO
COLLECT SAMPLES. The use of plastic bags
presents a contamination hazard to laboratory personnel and to other samples. When
these containers are opened, a bellows effect
blows fibers out of the container onto everything, including the person opening the container.
If a cork-borer type sampler is available,
push the tube through the material all the
way, so that all layers of material are sampled. Some samplers are intended to be disposable. These should be capped and sent to
the laboratory. If a non-disposable cork
borer is used, empty the contents into a scintillation vial and send to the laboratory.
Vigorously and completely clean the cork
borer between samples.

1.7. Physical and Chemical Properties
The nominal chemical compositions for
the asbestos minerals were given in Section
1. Compared to cleavage fragments of the
same minerals, asbestiform fibers possess a
high tensile strength along the fiber axis.
They are chemically inert, non- combustible,
and heat resistant. Except for chrysotile,
they are insoluble in Hydrochloric acid
(HCl). Chrysotile is slightly soluble in HCl.
Asbestos has high electrical resistance and
good sound absorbing characteristics. It can
be woven into cables, fabrics or other textiles, or matted into papers, felts, and mats.
1.8. Toxicology (This section is for Information Only and Should Not Be Taken as
OSHA Policy)

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§ 1910.1001

2.4 Shipment

Possible physiologic results of respiratory
exposure to asbestos are mesothelioma of the
pleura or peritoneum, interstitial fibrosis,
asbestosis, pneumoconiosis, or respiratory
cancer. The possible consequences of asbestos exposure are detailed in the NIOSH Criteria Document or in the OSHA Asbestos
Standards 29 CFR 1910.1001 and 29 CFR
1926.1101 and 29 CFR 1915.1001.

Samples packed in glass vials must not
touch or they might break in shipment.
(a) Seal the samples with a sample seal
over the end to guard against tampering and
to identify the sample.
(b) Package the bulk samples in separate
packages from the air samples. They may
cross-contaminate each other and will invalidate the results of the air samples.

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§ 1910.1001

29 CFR Ch. XVII (7–1–16 Edition)

(c) Include identifying paperwork with the
samples, but not in contact with the suspected asbestos.
(d) To maintain sample accountability,
ship the samples by certified mail, overnight
express, or hand carry them to the laboratory.

(h) High dispersion index of refraction oils
(Special for dispersion staining.)
n = 1.550
n = 1.585
n = 1.590
n = 1.605
n = 1.620
n = 1.670
n = 1.680
n = 1.690
(i) A set of index of refraction oils from
about n = 1.350 to n = 2.000 in n = 0.005 increments. (Standard for Becke line analysis.)
(j) Glass slides with painted or frosted ends
1 × 3 inches 1mm thick, precleaned.
(k) Cover Slips 22 × 22 mm, #11⁄2
(l) Paper clips or dissection needles
(m) Hand grinder
(n) Scalpel with both #10 and #11 blades
(o) 0.1 molar HCl
(p) Decalcifying solution (Baxter Scientific
Products) Ethylenediaminetetraacetic Acid,
Tetrasodium ..........................................0.7 g/l
Sodium Potassium Tartrate .........8.0 mg/liter
Hydrochloric Acid ..........................99.2 g/liter
Sodium Tartrate.............................0.14 g/liter

3. Analysis
The analysis of asbestos samples can be divided into two major parts: sample preparation and microscopy. Because of the different
asbestos uses that may be encountered by
the analyst, each sample may need different
preparation steps. The choices are outlined
below. There are several different tests that
are performed to identify the asbestos species and determine the percentage. They will
be explained below.
3.1. Safety
(a) Do not create unnecessary dust. Handle
the samples in HEPA-filter equipped hoods.
If samples are received in bags, envelopes or
other inappropriate container, open them
only in a hood having a face velocity at or
greater than 100 fpm. Transfer a small
amount to a scintillation vial and only handle the smaller amount.
(b) Open samples in a hood, never in the
open lab area.
(c) Index of refraction oils can be toxic.
Take care not to get this material on the
skin. Wash immediately with soap and water
if this happens.
(d) Samples that have been heated in the
muffle furnace or the drying oven may be
hot. Handle them with tongs until they are
cool enough to handle.
(e) Some of the solvents used, such as THF
(tetrahydrofuran), are toxic and should only
be handled in an appropriate fume hood and
according to instructions given in the Safety
data sheet (SDS).

(q) Tetrahydrofuran (THF)
(r) Hotplate capable of 60 °C
(s) Balance
(t) Hacksaw blade
(u) Ruby mortar and pestle
3.3. Sample Pre-Preparation
Sample preparation begins with pre-preparation which may include chemical reduction of the matrix, heating the sample to
dryness or heating in the muffle furnace. The
end result is a sample which has been reduced to a powder that is sufficiently fine to
fit under the cover slip. Analyze different
phases of samples separately, e.g., tile and
the tile mastic should be analyzed separately
as the mastic may contain asbestos while
the tile may not.

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3.2. Equipment

(a) Wet samples

(a) Phase contrast microscope with 10x, 16x
and 40x objectives, 10x wide-field eyepieces,
G–22 Walton-Beckett graticule, Whipple
disk, polarizer, analyzer and first order red
or gypsum plate, 100 Watt illuminator, rotating position condenser with oversize phase
rings, central stop dispersion objective,
Kohler illumination and a rotating mechanical stage.
(b) Stereo microscope with reflected light
illumination, transmitted light illumination, polarizer, analyzer and first order red
or gypsum plate, and rotating stage.
(c) Negative pressure hood for the stereo
microscope
(d) Muffle furnace capable of 600 °C
(e) Drying oven capable of 50–150 °C
(f) Aluminum specimen pans
(g) Tongs for handling samples in the furnace

Samples with a high water content will not
give the proper dispersion colors and must be
dried prior to sample mounting. Remove the
lid of the scintillation vial, place the bottle
in the drying oven and heat at 100 °C to dryness (usually about 2 h). Samples which are
not submitted to the lab in glass must be removed and placed in glass vials or aluminum
weighing pans before placing them in the
drying oven.
(b) Samples With Organic Interference—Muffle
Furnace
These may include samples with tar as a
matrix, vinyl asbestos tile, or any other organic that can be reduced by heating. Remove the sample from the vial and weigh in
a balance to determine the weight of the submitted portion. Place the sample in a muffle

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Occupational Safety and Health Admin., Labor
furnace at 500 °C for 1 to 2 h or until all obvious organic material has been removed. Retrieve, cool and weigh again to determine
the weight loss on ignition. This is necessary
to determine the asbestos content of the submitted sample, because the analyst will be
looking at a reduced sample.
NOTE: Heating above 600 °C will cause the
sample to undergo a structural change
which, given sufficient time, will convert the
chrysotile to forsterite. Heating even at
lower temperatures for 1 to 2 h may have a
measurable effect on the optical properties
of the minerals. If the analyst is unsure of
what to expect, a sample of standard asbestos should be heated to the same temperature for the same length of time so that it
can be examined for the proper interpretation.

shock occurs. (Freezer mills can completely
destroy the observable crystallinity of asbestos and should not be used). For some samples, a portion of material can be shaved off
with a scalpel, ground off with a hand grinder or hack saw blade.
The preparation tools should either be disposable or cleaned thoroughly. Use vigorous
scrubbing to loosen the fibers during the
washing. Rinse the implements with copious
amounts of water and air-dry in a dust-free
environment.
(2) If the sample is powder or has been reduced as in (1) above, it is ready to mount.
Place a glass slide on a piece of optical tissue and write the identification on the painted or frosted end. Place two drops of index of
refraction medium n = 1.550 on the slide.
(The medium n = 1.550 is chosen because it is
the matching index for chrysotile. Dip the
end of a clean paper-clip or dissecting needle
into the droplet of refraction medium on the
slide to moisten it. Then dip the probe into
the powder sample. Transfer what sticks on
the probe to the slide. The material on the
end of the probe should have a diameter of
about 3 mm for a good mount. If the material is very fine, less sample may be appropriate. For non-powder samples such as fiber
mats, forceps should be used to transfer a
small amount of material to the slide. Stir
the material in the medium on the slide,
spreading it out and making the preparation
as uniform as possible. Place a cover-slip on
the preparation by gently lowering onto the
slide and allowing it to fall ‘‘trapdoor’’ fashion on the preparation to push out any bubbles. Press gently on the cover slip to even
out the distribution of particulate on the
slide. If there is insufficient mounting oil on
the slide, one or two drops may be placed
near the edge of the coverslip on the slide.
Capillary action will draw the necessary
amount of liquid into the preparation. Remove excess oil with the point of a laboratory wiper.
Treat at least two different areas of each
phase in this fashion. Choose representative
areas of the sample. It may be useful to select particular areas or fibers for analysis.
This is useful to identify asbestos in severely
inhomogeneous samples.
When it is determined that amphiboles
may be present, repeat the above process
using the appropriate high-dispersion oils
until an identification is made or all six asbestos minerals have been ruled out. Note
that percent determination must be done in
the index medium 1.550 because amphiboles
tend to disappear in their matching mediums.

(c) Samples With Organic Interference—THF
Vinyl asbestos tile is the most common
material treated with this solvent, although,
substances containing tar will sometimes
yield to this treatment. Select a portion of
the material and then grind it up if possible.
Weigh the sample and place it in a test tube.
Add sufficient THF to dissolve the organic
matrix. This is usually about 4 to 5 mL. Remember, THF is highly flammable. Filter the
remaining material through a tared silver
membrane, dry and weigh to determine how
much is left after the solvent extraction.
Further process the sample to remove carbonate or mount directly.
(d) Samples With Carbonate Interference
Carbonate material is often found on fibers
and sometimes must be removed in order to
perform dispersion microscopy. Weigh out a
portion of the material and place it in a test
tube. Add a sufficient amount of 0.1 M HCl or
decalcifying solution in the tube to react all
the carbonate as evidenced by gas formation;
i.e., when the gas bubbles stop, add a little
more solution. If no more gas forms, the reaction is complete. Filter the material out
through a tared silver membrane, dry and
weigh to determine the weight lost.
3.4. Sample Preparation

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§ 1910.1001

Samples must be prepared so that accurate
determination can be made of the asbestos
type and amount present. The following
steps are carried out in the low-flow hood (a
low-flow hood has less than 50 fpm flow):
(1) If the sample has large lumps, is hard,
or cannot be made to lie under a cover slip,
the grain size must be reduced. Place a small
amount between two slides and grind the
material between them or grind a small
amount in a clean mortar and pestle. The
choice of whether to use an alumina, ruby,
or diamond mortar depends on the hardness
of the material. Impact damage can alter the
asbestos mineral if too much mechanical

3.5. Analytical Procedure
NOTE: This method presumes some knowledge of mineralogy and optical petrography.

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§ 1910.1001

29 CFR Ch. XVII (7–1–16 Edition)

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The analysis consists of three parts: The
determination of whether there is asbestos
present, what type is present and the determination of how much is present. The general flow of the analysis is:
(1) Gross examination.
(2) Examination under polarized light on
the stereo microscope.
(3) Examination by phase-polar illumination on the compound phase microscope.
(4) Determination of species by dispersion
stain. Examination by Becke line analysis

may also be used; however, this is usually
more cumbersome for asbestos determination.
(5) Difficult samples may need to be analyzed by SEM or TEM, or the results from
those techniques combined with light microscopy for a definitive identification. Identification of a particle as asbestos requires
that it be asbestiform. Description of particles should follow the suggestion of Campbell. (Figure 1)

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§ 1910.1001

have a very high tensile strength as demonstrated by bending without breaking. Asbestos fibers exist in bundles that are easily
parted, show longitudinal fine structure and
may be tufted at the ends showing ‘‘bundle
of sticks’’ morphology. In the microscope

For the purpose of regulation, the mineral
must be one of the six minerals covered and
must be in the asbestos growth habit. Large
specimen samples of asbestos generally have
the gross appearance of wood. Fibers are easily parted from it. Asbestos fibers are very
long compared with their widths. The fibers

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ER10AU94.007

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lpowell on DSK54DXVN1OFR with $$_JOB

§ 1910.1001

29 CFR Ch. XVII (7–1–16 Edition)

some of these properties may not be observable. Amphiboles do not always show striations along their length even when they are
asbestos. Neither will they always show tufting. They generally do not show a curved nature except for very long fibers. Asbestos and
asbestiform minerals are usually characterized in groups by extremely high aspect ratios (greater than 100:1). While aspect ratio
analysis is useful for characterizing populations of fibers, it cannot be used to identify
individual fibers of intermediate to short aspect ratio. Observation of many fibers is
often necessary to determine whether a sample consists of ‘‘cleavage fragments’’ or of asbestos fibers.
Most cleavage fragments of the asbestos
minerals are easily distinguishable from true
asbestos fibers. This is because true cleavage
fragments usually have larger diameters
than 1 μm. Internal structure of particles
larger than this usually shows them to have
no internal fibrillar structure. In addition,
cleavage fragments of the monoclinic
amphiboles show inclined extinction under
crossed polars with no compensator. Asbestos fibers usually show extinction at zero degrees or ambiguous extinction if any at all.
Morphologically, the larger cleavage fragments are obvious by their blunt or stepped
ends showing prismatic habit. Also, they
tend to be acicular rather than filiform.
Where the particles are less than 1 μm in
diameter and have an aspect ratio greater
than or equal to 3:1, it is recommended that
the sample be analyzed by SEM or TEM if
there is any question whether the fibers are
cleavage fragments or asbestiform particles.
Care must be taken when analyzing by
electron microscopy because the interferences are different from those in light microscopy and may structurally be very similar to asbestos. The classic interference is
between anthophyllite and biopyribole or intermediate fiber. Use the same morphological clues for electron microscopy as are
used for light microscopy, e.g. fibril splitting, internal longitudinal striation, fraying,
curvature, etc.
(1) Gross examination:
Examine the sample, preferably in the
glass vial. Determine the presence of any obvious fibrous component. Estimate a percentage based on previous experience and
current observation. Determine whether any
pre- preparation is necessary. Determine the
number of phases present. This step may be
carried out or augmented by observation at
6 to 40 × under a stereo microscope.
(2) After performing any necessary prepreparation, prepare slides of each phase as
described above. Two preparations of the
same phase in the same index medium can be
made side-by-side on the same glass for convenience. Examine with the polarizing stereo
microscope. Estimate the percentage of as-

bestos based on the amount of birefringent
fiber present.
(3) Examine the slides on the phase-polar
microscopes at magnifications of 160 and 400
× . Note the morphology of the fibers. Long,
thin, very straight fibers with little curvature are indicative of fibers from the
amphibole family. Curved, wavy fibers are
usually indicative of chrysotile. Estimate
the percentage of asbestos on the phase-polar
microscope under conditions of crossed
polars and a gypsum plate. Fibers smaller
than 1.0 μm in thickness must be identified
by inference to the presence of larger, identifiable fibers and morphology. If no larger fibers are visible, electron microscopy should
be performed. At this point, only a tentative
identification can be made. Full identification must be made with dispersion microscopy. Details of the tests are included in the
appendices.
(4) Once fibers have been determined to be
present, they must be identified. Adjust the
microscope for dispersion mode and observe
the fibers. The microscope has a rotating
stage, one polarizing element, and a system
for generating dark-field dispersion microscopy (see Section 4.6. of this appendix). Align
a fiber with its length parallel to the polarizer and note the color of the Becke lines.
Rotate the stage to bring the fiber length
perpendicular to the polarizer and note the
color. Repeat this process for every fiber or
fiber bundle examined. The colors must be
consistent with the colors generated by
standard asbestos reference materials for a
positive identification. In n = 1.550,
amphiboles will generally show a yellow to
straw-yellow color indicating that the fiber
indices of refraction are higher than the liquid. If long, thin fibers are noted and the colors are yellow, prepare further slides as
above in the suggested matching liquids listed below:
Type of asbestos
Chrysotile ...............................
Amosite ..................................
Crocidolite ..............................
Anthophyllite ..........................
Tremolite ................................
Actinolite ................................

Index of refraction
n
n
n
n
n
n

=
=
=
=
=
=

Where more than one liquid is suggested,
the first is preferred; however, in some cases
this liquid will not give good dispersion
color. Take care to avoid interferences in the
other liquid; e.g., wollastonite in n = 1.620
will give the same colors as tremolite. In n
= 1.605 wollastonite will appear yellow in all
directions. Wollastonite may be determined
under crossed polars as it will change from
blue to yellow as it is rotated along its fiber
axis by tapping on the cover slip. Asbestos
minerals will not change in this way.
Determination of the angle of extinction
may, when present, aid in the determination

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1.670 or 1.680.
1.690.
1.605 and 1.620.
1.605 and 1.620.
1.620.

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Occupational Safety and Health Admin., Labor
of anthophyllite from tremolite. True asbestos fibers usually have 0° extinction or ambiguous extinction, while cleavage fragments
have more definite extinction.
Continue analysis until both preparations
have been examined and all present species
of asbestos are identified. If there are no fibers present, or there is less than 0.1%
present, end the analysis with the minimum
number of slides (2).
(5) Some fibers have a coating on them
which makes dispersion microscopy very difficult or impossible. Becke line analysis or
electron microscopy may be performed in
those cases. Determine the percentage by
light microscopy. TEM analysis tends to
overestimate the actual percentage present.
(6) Percentage determination is an estimate of occluded area, tempered by gross observation. Gross observation information is
used to make sure that the high magnification microscopy does not greatly over- or
under- estimate the amount of fiber present.
This part of the analysis requires a great
deal of experience. Satisfactory models for
asbestos content analysis have not yet been
developed, although some models based on
metallurgical grain-size determination have
found some utility. Estimation is more easily handled in situations where the grain
sizes visible at about 160 × are about the
same and the sample is relatively homogeneous.
View all of the area under the cover slip to
make the percentage determination. View
the fields while moving the stage, paying attention to the clumps of material. These are
not usually the best areas to perform dispersion microscopy because of the interference
from other materials. But, they are the areas
most likely to represent the accurate percentage in the sample. Small amounts of asbestos require slower scanning and more frequent analysis of individual fields.
Report the area occluded by asbestos as
the concentration. This estimate does not
generally take into consideration the difference in density of the different species
present in the sample. For most samples this
is adequate. Simulation studies with similar
materials must be carried out to apply
microvisual estimation for that purpose and
is beyond the scope of this procedure.
(7) Where successive concentrations have
been made by chemical or physical means,
the amount reported is the percentage of the
material in the ‘‘as submitted’’ or original
state. The percentage determined by microscopy is multiplied by the fractions remaining after pre-preparation steps to give the
percentage in the original sample. For example:
Step 1. 60% remains after heating at 550 °C
for 1 h.
Step 2. 30% of the residue of step 1 remains
after dissolution of carbonate in 0.1 m HCl.

§ 1910.1001

Step 3. Microvisual estimation determines
that 5% of the sample is chrysotile asbestos.
The reported result is:
R = (Microvisual result in percent) × (Fraction remaining after step 2) × (Fraction remaining of original sample after step 1)
R = (5) × (.30) × (.60) = 0.9%
(8) Report the percent and type of asbestos
present. For samples where asbestos was
identified, but is less than 1.0%, report ‘‘Asbestos present, less than 1.0%.’’ There must
have been at least two observed fibers or
fiber bundles in the two preparations to be
reported as present. For samples where asbestos was not seen, report as ‘‘None Detected.’’
4. Auxiliary Information
Because of the subjective nature of asbestos analysis, certain concepts and procedures
need to be discussed in more depth. This information will help the analyst understand
why some of the procedures are carried out
the way they are.
4.1. Light
Light is electromagnetic energy. It travels
from its source in packets called quanta. It
is instructive to consider light as a plane
wave. The light has a direction of travel.
Perpendicular to this and mutually perpendicular to each other, are two vector components. One is the magnetic vector and the
other is the electric vector. We shall only be
concerned with the electric vector. In this
description, the interaction of the vector and
the mineral will describe all the observable
phenomena. From a light source such a microscope illuminator, light travels in all different direction from the filament.
In any given direction away from the filament, the electric vector is perpendicular to
the direction of travel of a light ray. While
perpendicular, its orientation is random
about the travel axis. If the electric vectors
from all the light rays were lined up by passing the light through a filter that would only
let light rays with electric vectors oriented
in one direction pass, the light would then be
POLARIZED.
Polarized light interacts with matter in
the direction of the electric vector. This is
the polarization direction. Using this property it is possible to use polarized light to
probe different materials and identify them
by how they interact with light.
The speed of light in a vacuum is a constant at about 2.99 × 108 m/s. When light travels in different materials such as air, water,
minerals or oil, it does not travel at this
speed. It travels slower. This slowing is a
function of both the material through which
the light is traveling and the wavelength or
frequency of the light. In general, the more

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§ 1910.1001

29 CFR Ch. XVII (7–1–16 Edition)

dense the material, the slower the light travels. Also, generally, the higher the frequency, the slower the light will travel. The
ratio of the speed of light in a vacuum to
that in a material is called the index of refraction (n). It is usually measured at 589 nm
(the sodium D line). If white light (light containing all the visible wavelengths) travels
through a material, rays of longer wavelengths will travel faster than those of shorter wavelengths, this separation is called dispersion. Dispersion is used as an identifier of
materials as described in Section 4.6.

tion to fiber length is used to aid in the identification of asbestos.
4.3. Polarized Light Technique
Polarized light microscopy as described in
this section uses the phase-polar microscope
described in Section 3.2. A phase contrast
microscope is fitted with two polarizing elements, one below and one above the sample.
The polarizers have their polarization directions at right angles to each other. Depending on the tests performed, there may be a
compensator between these two polarizing
elements. Light emerging from a polarizing
element has its electric vector pointing in
the polarization direction of the element.
The light will not be subsequently transmitted through a second element set at a
right angle to the first element. Unless the
light is altered as it passes from one element
to the other, there is no transmission of
light.

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4.2. Material Properties
Materials are either amorphous or crystalline. The difference between these two descriptions depends on the positions of the
atoms in them. The atoms in amorphous materials are randomly arranged with no long
range order. An example of an amorphous
material is glass. The atoms in crystalline
materials, on the other hand, are in regular
arrays and have long range order. Most of
the atoms can be found in highly predictable
locations. Examples of crystalline material
are salt, gold, and the asbestos minerals.
It is beyond the scope of this method to describe the different types of crystalline materials that can be found, or the full description of the classes into which they can fall.
However, some general crystallography is
provided below to give a foundation to the
procedures described.
With the exception of anthophyllite, all
the asbestos minerals belong to the
monoclinic crystal type. The unit cell is the
basic repeating unit of the crystal and for
monoclinic crystals can be described as having three unequal sides, two 90° angles and
one angle not equal to 90°. The orthorhombic
group, of which anthophyllite is a member
has three unequal sides and three 90° angles.
The unequal sides are a consequence of the
complexity of fitting the different atoms
into the unit cell. Although the atoms are in
a regular array, that array is not symmetrical in all directions. There is long range
order in the three major directions of the
crystal. However, the order is different in
each of the three directions. This has the effect that the index of refraction is different
in each of the three directions. Using polarized light, we can investigate the index of refraction in each of the directions and identify the mineral or material under investigation. The indices a, b, and g are used to identify the lowest, middle, and highest index of
refraction respectively. The x direction, associated with a is called the fast axis. Conversely, the z direction is associated with g
and is the slow direction. Crocidolite has a
along the fiber length making it ‘‘lengthfast’’. The remainder of the asbestos minerals have the g axis along the fiber length.
They are called ‘‘length-slow’’. This orienta-

4.4. Angle of Extinction
Crystals which have different crystal regularity in two or three main directions are
said to be anisotropic. They have a different
index of refraction in each of the main directions. When such a crystal is inserted between the crossed polars, the field of view is
no longer dark but shows the crystal in
color. The color depends on the properties of
the crystal. The light acts as if it travels
through the crystal along the optical axes. If
a crystal optical axis were lined up along one
of the polarizing directions (either the polarizer or the analyzer) the light would appear
to travel only in that direction, and it would
blink out or go dark. The difference in degrees between the fiber direction and the
angle at which it blinks out is called the
angle of extinction. When this angle can be
measured, it is useful in identifying the mineral. The procedure for measuring the angle
of extinction is to first identify the polarization direction in the microscope. A commercial alignment slide can be used to establish
the
polarization
directions
or
use
anthophyllite or another suitable mineral.
This mineral has a zero degree angle of extinction and will go dark to extinction as it
aligns with the polarization directions. When
a fiber of anthophyllite has gone to extinction, align the eyepiece reticle or graticule
with the fiber so that there is a visual cue as
to the direction of polarization in the field of
view. Tape or otherwise secure the eyepiece
in this position so it will not shift.
After the polarization direction has been
identified in the field of view, move the particle of interest to the center of the field of
view and align it with the polarization direction. For fibers, align the fiber along this direction. Note the angular reading of the rotating stage. Looking at the particle, rotate
the stage until the fiber goes dark or ‘‘blinks

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Occupational Safety and Health Admin., Labor
out’’. Again note the reading of the stage.
The difference in the first reading and the
second is an angle of extinction.
The angle measured may vary as the orientation of the fiber changes about its long
axis. Tables of mineralogical data usually report the maximum angle of extinction. Asbestos forming minerals, when they exhibit
an angle of extinction, usually do show an
angle of extinction close to the reported
maximum, or as appropriate depending on
the substitution chemistry.

the red color and gives the background a
characteristic red to red-magenta color. If
this ‘‘full-wave’’ compensator is in place
when the asbestos preparation is inserted
into the light train, the colors seen on the fibers are quite different. Gypsum, like asbestos has a fast axis and a slow axis. When a
fiber is aligned with its fast axis in the same
direction as the fast axis of the gypsum
plate, the ray vibrating in the slow direction
is retarded by both the asbestos and the gypsum. This results in a higher retardation
than would be present for either of the two
minerals. The color seen is a second order
blue. When the fiber is rotated 90° using the
rotating stage, the slow direction of the fiber
is now aligned with the fast direction of the
gypsum and the fast direction of the fiber is
aligned with the slow direction of the gypsum. Thus, one ray vibrates faster in the fast
direction of the gypsum, and slower in the
slow direction of the fiber; the other ray will
vibrate slower in the slow direction of the
gypsum and faster in the fast direction of
the fiber. In this case, the effect is subtractive and the color seen is a first order yellow. As long as the fiber thickness does not
add appreciably to the color, the same basic
colors will be seen for all asbestos types except crocidolite. In crocidolite the colors
will be weaker, may be in the opposite directions, and will be altered by the blue absorption color natural to crocidolite. Hundreds of
other materials will give the same colors as
asbestos, and therefore, this test is not definitive for asbestos. The test is useful in discriminating against fiberglass or other
amorphous fibers such as some synthetic fibers. Certain synthetic fibers will show retardation colors different than asbestos;
however, there are some forms of polyethylene and aramid which will show morphology and retardation colors similar to asbestos minerals. This test must be supplemented with a positive identification test
when birefringent fibers are present which
can not be excluded by morphology. This
test is relatively ineffective for use on fibers
less than 1 μm in diameter. For positive confirmation TEM or SEM should be used if no
larger bundles or fibers are visible.

4.5. Crossed Polars with Compensator

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§ 1910.1001

When the optical axes of a crystal are not
lined up along one of the polarizing directions (either the polarizer or the analyzer)
part of the light travels along one axis and
part travels along the other visible axis. This
is characteristic of birefringent materials.
The color depends on the difference of the
two visible indices of refraction and the
thickness of the crystal. The maximum difference available is the difference between
the a and the g axes. This maximum difference is usually tabulated as the
birefringence of the crystal.
For this test, align the fiber at 45° to the
polarization directions in order to maximize
the contribution to each of the optical axes.
The colors seen are called retardation colors.
They arise from the recombination of light
which has traveled through the two separate
directions of the crystal. One of the rays is
retarded behind the other since the light in
that direction travels slower. On recombination, some of the colors which make up
white light are enhanced by constructive interference and some are suppressed by destructive interference. The result is a color
dependent on the difference between the indices and the thickness of the crystal. The
proper colors, thicknesses, and retardations
are shown on a Michel-Levy chart. The three
items,
retardation,
thickness
and
birefringence are related by the following relationship:
R = t(nγ—nα)
R = retardation, t = crystal thickness in μm,
and
nα,γ = indices of refraction.
Examination of the equation for asbestos
minerals reveals that the visible colors for
almost all common asbestos minerals and
fiber sizes are shades of gray and black. The
eye is relatively poor at discriminating different shades of gray. It is very good at discriminating different colors. In order to
compensate for the low retardation, a compensator is added to the light train between
the polarization elements. The compensator
used for this test is a gypsum plate of known
thickness and birefringence. Such a compensator when oriented at 45° to the polarizer direction, provides a retardation of 530 nm of
the 530 nm wavelength color. This enhances

4.6. Dispersion Staining
Dispersion microscopy or dispersion staining is the method of choice for the identification of asbestos in bulk materials. Becke
line analysis is used by some laboratories
and yields the same results as does dispersion staining for asbestos and can be used in
lieu of dispersion staining. Dispersion staining is performed on the same platform as the
phase-polar analysis with the analyzer and
compensator removed. One polarizing element remains to define the direction of the

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§ 1910.1001

29 CFR Ch. XVII (7–1–16 Edition)

light so that the different indices of refraction of the fibers may be separately determined. Dispersion microscopy is a dark-field
technique when used for asbestos. Particles
are imaged with scattered light. Light which
is unscattered is blocked from reaching the
eye either by the back field image mask in a
McCrone objective or a back field image
mask in the phase condenser. The most convenient method is to use the rotating phase
condenser to move an oversized phase ring
into place. The ideal size for this ring is for
the central disk to be just larger than the
objective entry aperture as viewed in the
back focal plane. The larger the disk, the
less scattered light reaches the eye. This will
have the effect of diminishing the intensity
of dispersion color and will shift the actual
color seen. The colors seen vary even on microscopes from the same manufacturer. This
is due to the different bands of wavelength
exclusion by different mask sizes. The mask
may either reside in the condenser or in the
objective back focal plane. It is imperative
that the analyst determine by experimentation with asbestos standards what the appropriate colors should be for each asbestos
type. The colors depend also on the temperature of the preparation and the exact chemistry of the asbestos. Therefore, some slight
differences from the standards should be allowed. This is not a serious problem for commercial asbestos uses. This technique is used
for identification of the indices of refraction
for fibers by recognition of color. There is no
direct numerical readout of the index of refraction. Correlation of color to actual index
of refraction is possible by referral to published conversion tables. This is not necessary for the analysis of asbestos. Recognition of appropriate colors along with the
proper morphology are deemed sufficient to
identify the commercial asbestos minerals.
Other techniques including SEM, TEM, and
XRD may be required to provide additional
information in order to identify other types
of asbestos.
Make a preparation in the suspected
matching high dispersion oil, e.g., n = 1.550
for chrysotile. Perform the preliminary tests
to determine whether the fibers are
birefringent or not. Take note of the morphological character. Wavy fibers are indicative of chrysotile while long, straight, thin,
frayed fibers are indicative of amphibole asbestos. This can aid in the selection of the
appropriate matching oil. The microscope is
set up and the polarization direction is noted
as in Section 4.4. Align a fiber with the polarization direction. Note the color. This is
the color parallel to the polarizer. Then rotate the fiber rotating the stage 90° so that
the polarization direction is across the fiber.
This is the perpendicular position. Again
note the color. Both colors must be consistent with standard asbestos minerals in
the correct direction for a positive identi-

fication of asbestos. If only one of the colors
is correct while the other is not, the identification is not positive. If the colors in both
directions are bluish-white, the analyst has
chosen a matching index oil which is higher
than the correct matching oil, e.g. the analyst has used n = 1.620 where chrysotile is
present. The next lower oil (Section 3.5.)
should be used to prepare another specimen.
If the color in both directions is yellowwhite to straw-yellow-white, this indicates
that the index of the oil is lower than the
index of the fiber, e.g. the preparation is in
n = 1.550 while anthophyllite is present. Select the next higher oil (Section 3.5.) and prepare another slide. Continue in this fashion
until a positive identification of all asbestos
species present has been made or all possible
asbestos species have been ruled out by negative results in this test. Certain plant fibers
can have similar dispersion colors as asbestos. Take care to note and evaluate the morphology of the fibers or remove the plant fibers in pre- preparation. Coating material on
the fibers such as carbonate or vinyl may destroy the dispersion color. Usually, there
will be some outcropping of fiber which will
show the colors sufficient for identification.
When this is not the case, treat the sample
as described in Section 3.3. and then perform
dispersion staining. Some samples will yield
to Becke line analysis if they are coated or
electron microscopy can be used for identification.
5. References
5.1. Crane, D.T., Asbestos in Air, OSHA
method ID160, Revised November 1992.
5.2. Ford, W.E., Dana’s Textbook of Mineralogy; Fourth Ed.; John Wiley and Son,
New York, 1950, p. vii.
5.3. Selikoff,.I.J., Lee, D.H.K., Asbestos and
Disease, Academic Press, New York, 1978, pp.
3,20.
5.4. Women Inspectors of Factories. Annual
Report for 1898, H.M. Statistical Office, London, p. 170 (1898).
5.5. Selikoff, I.J., Lee, D.H.K., Asbestos and
Disease, Academic Press, New York, 1978, pp.
26,30.
5.6. Campbell, W.J., et al, Selected Silicate
Minerals and Their Asbestiform Varieties,
United States Department of the Interior,
Bureau of Mines, Information Circular 8751,
1977.
5.7. Asbestos, Code of Federal Regulations,
29 CFR 1910.1001 and 29 CFR 1926.58.
5.8. National Emission Standards for Hazardous Air Pollutants; Asbestos NESHAP Revision, FEDERAL REGISTER, Vol. 55, No. 224, 20
November 1990, p. 48410.
5.9. Ross, M. The Asbestos Minerals: Definitions, Description, Modes of Formation, Physical and Chemical Properties and Health Risk to
the Mining Community, Nation Bureau of
Standards Special Publication, Washington,
DC, 1977.

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Occupational Safety and Health Admin., Labor
5.10. Lilis, R., Fibrous Zeolites and Endemic Mesothelioma in Cappadocia, Turkey,
J. Occ Medicine, 1981, 23,(8),548–550.
5.11. Occupational Exposure to Asbestos—
1972, U.S. Department of Health, Education
and Welfare, Public Health Service, Center
for Disease Control, National Institute for
Occupational Safety and Health, HSM–72–
10267.
5.12. Campbell, W.J., et al, Relationship of
Mineral Habit to Size Characteristics for
Tremolite Fragments and Fibers, United States
Department of the Interior, Bureau of Mines,
Information Circular 8367, 1979.
5.13. Mefford, D., DCM Laboratory, Denver,
private communication, July 1987.
5.14. Deer, W.A., Howie, R.A., Zussman, J.,
Rock Forming Minerals, Longman, Thetford,
UK, 1974.
5.15. Kerr, P.F., Optical Mineralogy; Third
Ed. McGraw-Hill, New York, 1959.
5.16. Veblen, D.R. (Ed.), Amphiboles and
Other Hydrous Pyriboles—Mineralogy, Reviews
in Mineralogy, Vol 9A, Michigan, 1982, pp 1–
102.
5.17. Dixon, W.C., Applications of Optical Microscopy in the Analysis of Asbestos and
Quartz, ACS Symposium Series, No. 120, Analytical Techniques in Occupational Health
Chemistry, 1979.
5.18. Polarized Light Microscopy, McCrone
Research Institute, Chicago, 1976.
5.19. Asbestos Identification, McCrone Research Institute, G & G printers, Chicago,
1987.
5.20. McCrone, W.C., Calculation of Refractive Indices from Dispersion Staining Data,
The Microscope, No 37, Chicago, 1989.
5.21. Levadie, B. (Ed.), Asbestos and Other
Health Related Silicates, ASTM Technical
Publication 834, ASTM, Philadelphia 1982.
5.22. Steel, E. and Wylie, A., Riordan, P.H.
(Ed.), Mineralogical Characteristics of Asbestos, Geology of Asbestos Deposits, pp. 93–101,
SME-AIME, 1981.
5.23. Zussman, J., The Mineralogy of Asbestos, Asbestos: Properties, Applications and Hazards, pp. 45–67 Wiley, 1979.

4) is not covered under the ‘‘coal tar
pitch volatiles’’ standard.
[48 FR 2768, Jan. 21, 1983]

§ 1910.1003 13
Carcinogens
Nitrobiphenyl, etc.).

4-Nitrobiphenyl, Chemical Abstracts Service
Register Number (CAS No.) 92933;
alpha-Naphthylamine, CAS No. 134327;
methyl chloromethyl ether, CAS No. 107302;
3,′-Dichlorobenzidine (and its salts) CAS No.
91941;
bis-Chloromethyl ether, CAS No. 542881;
beta-Naphthylamine, CAS No. 91598;
Benzidine, CAS No. 92875;
4-Aminodiphenyl, CAS No. 92671;
Ethyleneimine, CAS No. 151564;
beta-Propiolactone, CAS No. 57578;
2-Acetylaminofluorene, CAS No. 53963;
4-Dimethylaminoazo-benezene,
CAS
No.
60117; and
N-Nitrosodimethylamine, CAS No. 62759.

(2) This section shall not apply to the
following:
(i) Solid or liquid mixtures containing less than 0.1 percent by weight
or volume of 4–Nitrobiphenyl; methyl
chloromethyl ether; bis-chloromethyl
ether; beta-Naphthylamine; benzidine
or 4–Aminodiphenyl; and
(ii) Solid or liquid mixtures containing less than 1.0 percent by weight
or volume of alpha-Naphthylamine; 3,′Dichlorobenzidine
(and
its
salts);
Ethyleneimine; beta-Propiolactone; 2Acetylaminofluorene;
4Dimethylaminoazobenzene,
or
NNitrosodimethylamine.
(b) Definitions. For the purposes of
this section:
Absolute filter is one capable of retaining 99.97 percent of a mono disperse
aerosol of 0.3 μm particles.
Authorized employee means an employee whose duties require him to be
in the regulated area and who has been
specifically assigned by the employer.
Clean change room means a room
where employees put on clean clothing

EDITORIAL NOTE: For FEDERAL REGISTER citations affecting § 1910.1001, see the List of
CFR Sections Affected, which appears in the
Finding Aids section of the printed volume
and at www.fdsys.gov.

§ 1910.1002 Coal tar pitch volatiles; interpretation of term.
As used in § 1910.1000 (Table Z-1), coal
tar pitch volatiles include the fused
polycyclic hydrocarbons which volatilize from the distillation residues of
coal, petroleum (excluding asphalt),
wood, and other organic matter. Asphalt (CAS 8052–42–4, and CAS 64742–93–

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(a) Scope and application. (1) This section applies to any area in which the 13
carcinogens addressed by this section
are manufactured, processed, repackaged, released, handled, or stored, but
shall not apply to transshipment in
sealed containers, except for the labeling requirements under paragraphs
(e)(2), (3) and (4) of this section. The 13
carcinogens are the following:

[51 FR 22733, June 20, 1986]

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