WAC 296-62-07753
Appendix J--Polarized light microscopy of asbestos--Nonmandatory.
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-WISHA.
Similar products from other sources may be substituted.
(1) Introduction
This method describes the collection and analysis of asbestos bulk materials
by light microscopy techniques including phase- polar 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:
Asbestos Fiber: A fiber of asbestos meeting the criteria
for a fiber. (See section (3)(e))
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 microns with a length to
width ratio greater than or equal to 3:1. This may include cleavage fragments.
(See section (3)(e) 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 micron 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.
(a) History
Light microscopy has been used for well over 100 years for the determination
of mineral species. This analysis is carried out 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. X-ray diffraction was partially
successful in determining the mineral types but was unable to separate
out the fibrous portions from the nonfibrous 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 nonfibrous 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 microscopes 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 micron 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 for fiber identification. Most fibers thicker than 1 micron
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.
(b) 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 traveling 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 micron. Because WISHA 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 micron 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.
(c) Advantages and Disadvantages
The advantages of light microscopy are:
(i) Basic identification of the materials was first performed by
light microscopy and gross analysis. This provides a large base of
published information against which to check analysis and analytical
technique.
(ii) 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.
(iii) The analysis is quick, requires little preparation time, and
can be performed on-site if a suitably equipped microscope is available.
The disadvantages are:
(iv) 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.
(v) 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.
(vi) 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.
(vii) Fibers may be bound in a matrix and not distinguishable as
fibers so identification cannot be made.
(d) Method Performance
(i) 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.
(ii) 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 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.
(iii) 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.
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 fibrous quality, having the appearance of plant
fibers. The analyst's ability to deal with these materials increases
with experience.
(f) 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.
(g) Physical and Chemical Properties
The nominal chemical compositions for the asbestos minerals were given
in subsection (1). Compared to cleavage fragments of the same minerals,
asbestiform fibers possess a high tensile strength along the fiber axis.
They are chemically inert, noncombustible, 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.
(h) Toxicology (This Section is for Information Only and Should Not
Be Taken as WISHA Policy).
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 WISHA Asbestos Standards, WAC 296-62-077.
(2) Sampling Procedure
(a) Equipment for Sampling
(i) Tube or cork borer sampling device
(ii) Knife
(iii) 20 mL scintillation vial or similar vial
(iv) Sealing encapsulant
(b) 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:
(i) Do not make unnecessary dust.
(ii) Take only a small amount (1 to 2 g).
(iii) Tightly close the sample container.
(iv) Use encapsulant to seal the spot where the sample was taken,
if necessary.
(c) 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 nondisposable 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.
(d) Shipment
Samples packed in glass vials must not touch or they might break in
shipment.
(i) Seal the samples with a sample seal over the end to guard against
tampering and to identify the sample.
(ii) 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.
(iii) Include identifying paperwork with the samples, but not in
contact with the suspected asbestos.
(iv) To maintain sample accountability, ship the samples by certified
mail, overnight express, or hand carry them to the laboratory.
(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.
(a) Safety
(i) 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.
(ii) Open samples in a hood, never in the open lab area.
(iii) 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.
(iv) 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.
(v) 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 Material Safety Data Sheet (MSDS).
Figure 1: Walton-Beckett Graticule with some
explanatory fibers.
Counts for the Fibers in the Figure
Structure No.
Count
Explanation
1 to 6
1
Single fibers all contained within the
circle.
7
1/2
Fiber crosses circle once.
8
0
Fiber too short.
9
2
Two crossing fibers.
10
0
Fiber outside graticule.
11
0
Fiber crosses graticule twice.
12
1/2
Although split, fiber only crosses once.
(b) Equipment
(i) 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. (See Figure 1).
(ii) Stereo microscope with reflected light illumination, transmitted
light illumination, polarizer, analyzer and first order red or gypsum
plate, and rotating stage.
(iii) Negative pressure hood for the stereo microscope
(iv) Muffle furnace capable of 600 degrees C
(v) Drying oven capable of 50-150 degrees C
(vi) Aluminum specimen pans
(vii) Tongs for handling samples in the furnace
(viii) 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
(ix) 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.)
(x) Glass slides with painted or frosted ends 1 x 3 inches 1mm thick,
precleaned.
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.
(i) Wet Samples
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 degrees 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.
(ii) 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 furnace at 500 degrees
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.
Notes: Heating above 600 degrees 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.
(iii) 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.
(iv) 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.
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):
(i) 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 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 hacksaw 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.
(ii) If the sample is powder or has been reduced as in (i) 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 nonpowder 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.
(e) Analytical procedure
Note: This method presumes some knowledge of mineralogy
and optical petrography.
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:
(i) Gross examination.
(ii) Examination under polarized light on the stereo microscope.
(iii) Examination by phase-polar illumination on the compound phase
microscope.
(iv) Determination of species by dispersion stain. Examination by
Becke line analysis may also be used; however, this is usually more
cumbersome for asbestos determination.
Figure 1. Particle definitions showing mineral growth
habits.
From the U.S. Bureau of Mines
(v) 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 2)
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 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 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 micron. 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 micron 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.
(vi) 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 6x to 40x under a stereo
microscope.
(vii) After performing any necessary pre-preparation, 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 asbestos based on the amount of birefringent fiber
present.
(viii) Examine the slides on the phase-polar microscopes at magnifications
of 160x and 400x. 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 microns 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.
(ix) 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
subsection (4)(f) 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
Index of
refraction
Chrysotile
n = 1.550.
Amosite
n = 1.670 or
1.680.
Crocidolite
n = 1.690.
Anthophyllite
n = 1.605 and
1.620.
Tremolite
n = 1.605 and
1.620.
Actinolite
n = 1.620.
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 of anthophyllite from tremolite. True asbestos fibers
usually have 0 degree 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).
(x) 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.
(xi) 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 160x 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.
(xii) 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 degrees C for 1 h.
Step 2. 30% of the residue of step 1 remains after dissolution
of carbonate in 0.1 m
HCl.
Step 3. Microvisual estimation determines that 5% of the sample
is chrysotile asbestos.
The reported result is:
R = (Microvisual result in percent)x(Fraction remaining after step
2)x(Fraction remaining of original sample after step 1)
R = (5)x(.30)x(.60) = 0.9%
(xiii) 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.”
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.
(a) 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 2.99þ108 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 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)(f).
(b) 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 degrees angles and one angle not
equal to 90 degrees. The orthorhombic group, of which anthophyllite
is a member has three unequal sides and three 90 degrees 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 alpha, beta, and gamma are used to identify the lowest,
middle, and highest index of refraction respectively. The x direction,
associated with alpha is called the fast axis. Conversely, the z direction
is associated with gamma and is the slow direction. Crocidolite has
alpha along the fiber length making it “length-fast.” The remainder
of the asbestos minerals have the gamma axis along the fiber length.
They are called “length-slow.” This orientation to fiber length is used
to aid in the identification of asbestos.
(c) Polarized Light Technique
Polarized light microscopy as described in this section uses the phase-polar
microscope described in Section (3)(b). 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.
(d) 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 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.
(e) Crossed Polars With Compensator
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 alpha and the gamma axises. This maximum
difference is usually tabulated as the birefringence of the crystal.
For this test, align the fiber at 45 degrees 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: Lambda
R = retardation,
t = crystal thickness in micron, and
alpha, gamma = 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 degrees to the polarizer direction,
provides a retardation of 530 nm of the 530 nm wavelength color. This
enhances 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 degrees 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 micron in diameter. For positive confirmation TEM or SEM
should be used if no larger bundles or fibers are visible.
(f) 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 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)(d).
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 degrees 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 identification 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)(e)) should be used to prepare
another specimen. If the color in both directions is yellow-white 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)(e))
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)(c) 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.
Crane, D.T., Asbestos in Air, OSHA method ID160, Revised November 1992.
Ford, W.E., Dana's Textbook of Mineralogy; Fourth Ed.; John Wiley and
Son, New York, 1950, p. vii.
Selikoff,.I.J., Lee, D.H.K., Asbestos and Disease, Academic Press, New
York, 1978, pp. 3, 20.
Women Inspectors of Factories. Annual Report for 1898, H.M. Statistical
Office, London, p. 170 (1898).
Selikoff,.I.J., Lee, D.H.K., Asbestos and Disease, Academic Press, New
York, 1978, pp. 26, 30.
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.
Asbestos, Code of Federal Regulations, 29 CFR 1910.1001 and 29 CFR 1926.58.
National Emission Standards for Hazardous Air Pollutants; Asbestos NESHAP
Revision, Federal Register, Vol. 55, No. 224, 20 November 1990, p. 48410.
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, D.C., 1977.
Lilis, R., Fibrous Zeolites and Endemic Mesothelioma in Cappadocia, Turkey,
J. Occ Medicine, 1981, 23, (8), 548-550.
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.
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.
Mefford, D., DCM Laboratory, Denver, private communication, July 1987.
Kerr, P.F., Optical Mineralogy; Third Ed. McGraw-Hill, New York, 1959.
Veblen, D.R. (Ed.), Amphiboles and Other Hydrous Pyriboles-Mineralogy,
Reviews in Mineralogy, Vol. 9A, Michigan, 1982, pp 1-102.
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.
Polarized Light Microscopy, McCrone Research Institute, Chicago, 1976.
Asbestos Identification, McCrone Research Institute, G & G printers,
Chicago, 1987.
McCrone, W.C., Calculation of Refractive Indices from Dispersion Staining
Data, The Microscope, No. 37, Chicago, 1989.
Levadie, B. (Ed.), Asbestos and Other Health Related Silicates, ASTM
Technical Publication 834, ASTM, Philadelphia 1982.
Steel, E. and Wylie, A., Riordan, P.H. (Ed.), Mineralogical Characteristics
of Asbestos, Geology of Asbestos Deposits, pp. 93-101, SME-AIME, 1981.
Zussman, J., The Mineralogy of Asbestos, Asbestos: Properties, Applications
and Hazards, pp. 45-67 Wiley, 1979.
WAC 296-62-07755
Appendix K--Smoking cessation program information for asbestos, tremolite,
anthophyllite, and actinolite--Nonmandatory.
The following organizations provide smoking cessation information and
program material:
(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, N.E., 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 states 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 nonsmokers' 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, United States 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-related 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 telephone
directory for listings of local chapters.
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