Public Health Statement for Asbestos
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This Public Health Statement is the summary chapter from the Toxicological Profile for Asbestos. It is one in a series of Public Health Statements about hazardous substances and their health effects. A shorter version, the ToxFAQs™, is also available. This information is important because this substance may harm you. The effects of exposure to any hazardous substance depend on the dose, the duration, how you are exposed, personal traits and habits, and whether other chemicals are present. For more information, call the ATSDR Information Center at 1-888-422-8737.
This public health statement tells you about asbestos and the effects of exposure. The Environmental Protection Agency (EPA) identifies the most serious hazardous waste sites in the nation. These sites make up the National Priorities List (NPL) and are the sites targeted for long-term federal cleanup activities. Asbestos has been found in at least 83 of the 1,585 current or former NPL sites. However, the total number of NPL sites evaluated for this substance is not known. As more sites are evaluated, the sites at which asbestos is found may increase. This information is important because exposure to this substance may harm you and because these sites may be sources of exposure.
When a substance is released from a large area, such as an industrial plant, or from a container, such as a drum or bottle, it enters the environment. This release does not always lead to exposure. You are exposed to a substance only when you come in contact with it. You may be exposed by breathing, eating, or drinking the substance, or by skin contact.
If you are exposed to asbestos, many factors determine whether you'll be harmed. These factors include the dose (how much), the duration (how long), the fiber type (mineral form and size distribution), and how you come in contact with it. You must also consider the other chemicals you're exposed to and your age, sex, diet, family traits, lifestyle (including whether you smoke tobacco), and state of health.
What is asbestos?
Asbestos is the name given to a group
of six different fibrous minerals (amosite, chrysotile, crocidolite,
and the fibrous varieties of tremolite, actinolite, and anthophyllite)
that occur naturally in the environment. One of these, namely
chrysotile, belongs to the serpentine family of minerals,
while all of the others belong to the amphibole family. All
forms of asbestos are hazardous, and all can cause cancer,
but amphibole forms of asbestos are considered to be somewhat
more hazardous to health than chrysotile. Asbestos minerals
consist of thin, separable fibers that have a parallel arrangement.
Nonfibrous forms of tremolite, actinolite, and anthophyllite
also are found naturally. However, because they are not fibrous,
they are not classified as asbestos minerals. Amphibole asbestos
fibers are generally brittle and often have a rod- or needle-like
shape, whereas chrysotile asbestos fibers are flexible and
curved. Chrysotile, also known as white asbestos, is the predominant
commercial form of asbestos; amphiboles are of minor commercial
importance. Asbestos fibers do not have any detectable odor
or taste. They do not dissolve in water or evaporate and are
resistant to heat, fire, chemical and biological degradation.
Because of these properties, asbestos has been mined for use
in a wide range of manufactured products, mostly in building
materials, friction products, and heat-resistant fabrics.
Since asbestos fibers may cause harmful health effects in
people who are exposed, all new uses of asbestos have been banned in the United States by the EPA. Please see the toxicological
profile for more information on the properties and uses of
What happens to asbestos when it enters the environment?
Asbestos fibers do not evaporate into
air or dissolve in water. However, pieces of fibers can enter
the air and water from the weathering of natural deposits
and the wearing down of manufactured asbestos products. Small
diameter fibers and fiber-containing particles may remain
suspended in the air for a long time and be carried long distances
by wind or water currents before settling. Larger diameter
fibers and particles tend to settle more quickly. Asbestos
fibers are not able to move through soil. They are generally
not broken down to other compounds in the environment and
will remain virtually unchanged over long periods. However,
the most common form of asbestos, chrysotile, may have some
minor mineral loss in acidic environments. Asbestos fibers
may break into shorter pieces or separate into a larger number
of individual fibers as a result of physical processes. When
asbestos fibers are breathed in, they may get trapped in the
lungs. Levels of fibers in lung tissue build up over time,
but some fibers, particularly chrysotile fibers, can be removed
from or degraded in the lung with time. Please see the toxicological
profile for more information on the behavior of asbestos in
How might I be exposed to asbestos?
Asbestos minerals are widespread in the
environment. They may occur in large natural deposits, or
as contaminants in other minerals. For example, tremolite
asbestos may occur in deposits of chrysotile, vermiculite,
and talc. Asbestos may be found in soil that is formed from
the erosion of asbestos-bearing rock. You are most likely
to be exposed to asbestos by breathing in asbestos fibers
that are suspended in air. These fibers can come from naturally
occurring sources of asbestos or from the wearing down or
disturbance of manufactured products including insulation,
automotive brakes and clutches, ceiling and floor tiles, dry
wall, roof shingles, and cement. However, these products do
not always contain asbestos. Low levels of asbestos that present
little, if any, risk to your health can be detected in almost
any air sample. For example, 10 fibers are typically present
in a cubic meter (fibers/m3) of outdoor air in rural
areas. (A cubic meter is about the amount of air that you
breathe in 1 hour.) Health professionals often report the
number of fibers in a milliliter (mL) (equivalent to a cubic
centimeter [cm3]) of air rather than in a cubic meter
of air. Since there are one million cm3 (or one million
mL) in a cubic meter, there typically would be 0.00001 fibers/mL
of asbestos in air in rural areas. Typical levels found in
cities are about 10-fold higher.
Close to an asbestos mine or factory,
levels may reach 10,000 fibers/m3 (0.01 fibers/mL) or
higher. Levels could also be above average near a building
that contains asbestos products and that is being torn down
or renovated or near a waste site where asbestos is not properly
covered up or stored to protect it from wind erosion.
In indoor air, the concentration of asbestos
depends on whether asbestos was used for insulation, ceiling
or floor tiles, or other purposes, and whether these asbestos-containing
materials are in good condition or are deteriorated and easily
crumbled. Concentrations measured in homes, schools, and other
buildings that contain asbestos range from about 30 to 6,000
fibers/m3 (0.00003–0.006 fibers/mL). People who work
with asbestos or asbestos-containing products (for example,
miners, insulation workers, asbestos abatement workers, and
automobile brake mechanics) without proper protection are
likely to be exposed to much higher levels of asbestos fibers
in air. In addition, custodial and maintenance workers who
are making repairs or installations in buildings with asbestos-containing
materials may be exposed to higher levels of asbestos. Since
vermiculite and talc may contain asbestos, occupational workers
and the general population may be exposed to asbestos when
using these products.
You can also be exposed to asbestos by
drinking asbestos fibers that are present in water. Even though
asbestos does not dissolve in water, fibers can enter water
by being eroded from natural deposits or piles of waste asbestos,
from asbestos-containing cement pipes used to carry drinking
water, or from filtering through asbestos-containing filters.
Most drinking water supplies in the United States have concentrations
of less than 1 million fibers per liter (MFL), even in areas
with asbestos deposits or with asbestos-cement water supply
pipes. However, in some locations, water samples may contain
10–300 million fibers per liter or even higher. The average
person drinks about 2 liters of water per day. Please see
the toxicological profile for more information on how you
could be exposed to asbestos.
How can asbestos enter and leave my body?
If you breathe asbestos fibers into your
lungs, some of the fibers will be deposited in the air passages
and on the cells that make up your lungs. Most fibers are
removed from your lungs by being carried away or coughed up
in a layer of mucus to the throat, where they are swallowed
into the stomach. This usually takes place within a few hours.
Fibers that are deposited in the deepest parts of the lung
are removed more slowly. In fact, some fibers may move through
your lungs and can remain in place for many years and may
never be removed from your body. Amphibole asbestos fibers
are retained in the lung longer than chrysotile asbestos fibers.
If you swallow asbestos fibers (either
those present in water or those that are moved to your throat
from your lungs), nearly all of the fibers pass along your
intestines within a few days and are excreted in the feces.
A small number of fibers may penetrate into cells that line
your stomach or intestines, and a few penetrate all the way
through and get into your blood. Some of these become trapped
in other tissues, and some are removed in your urine.
If you get asbestos fibers on your skin,
very few of these fibers, if any, pass through the skin into
your body. Please see the toxicological profile for more information
on how asbestos enters and leaves your body.
How can asbestos affect my health?
To protect the public from the harmful
effects of toxic chemicals and to find ways to treat people
who have been harmed, scientists use many tests.
One way to see if a chemical will hurt
people is to learn how the chemical is absorbed, used, and
released by the body; for some chemicals, animal testing may
be necessary. Animal testing may also be used to identify
health effects such as cancer or birth defects. Without laboratory
animals, scientists would lose a basic method to get information
needed to make wise decisions to protect public health. Scientists
have the responsibility to treat research animals with care
and compassion. Laws today protect the welfare of research
animals, and scientists must comply with strict animal care
Information on the health effects of
asbestos in people comes mostly from studies of people who
were exposed in the past to levels of asbestos fibers (greater
than or equal to 5 µm in length) in workplace air that were
as high as 5 million fibers/m3 (5 fibers/mL). Workers
who repeatedly breathe in asbestos fibers with lengths greater
than or equal to 5 µm may develop a slow buildup of scar-like
tissue in the lungs and in the membrane that surrounds the
lungs. This scar-like tissue does not expand and contract
like normal lung tissue and so breathing becomes difficult.
Blood flow to the lung may also be decreased, and this causes
the heart to enlarge. This disease is called asbestosis. People
with asbestosis have shortness of breath, often accompanied
by a cough. This is a serious disease and can eventually lead
to disability or death in people exposed to high amounts of
asbestos over a long period. However, asbestosis is not usually
of concern to people exposed to low levels of asbestos. Changes
in the membrane surrounding the lung, called pleural plaques,
are quite common in people occupationally exposed to asbestos
and are sometimes found in people living in areas with high
environmental levels of asbestos.
Effects on breathing from pleural plaques
alone are usually not serious. There is conflicting evidence
as to whether their presence in a person accurately predicts
more serious disease development in the future.
Asbestos workers have increased chances
of getting two principal types of cancer: cancer of the lung
tissue itself and mesothelioma, a cancer of the thin membrane
that surrounds the lung and other internal organs. These diseases
do not develop immediately following exposure to asbestos,
but appear only after a number of years. There is also some
evidence from studies of workers that breathing asbestos can
increase the chances of getting cancer in other locations
(for example, the stomach, intestines, esophagus, pancreas,
and kidneys), but this is less certain. Members of the public
who are exposed to lower levels of asbestos may also have
increased chances of getting cancer, but the risks are usually
small and are difficult to measure directly. Lung cancer is
usually fatal, while mesothelioma is almost always fatal,
often within a few months of diagnosis. Some scientists believe
that early identification and intervention of mesothelioma
may increase survival.
The levels of asbestos in air that lead
to lung disease depend on several factors. The most important
of these are (1) how long you were exposed, (2) how long it
has been since your exposure started, and (3) whether you
smoked cigarettes. Cigarette smoking and asbestos exposure
increase your chances of getting lung cancer. Also, there
is a scientific debate concerning the differences in the extent
of disease caused by different fiber types and sizes. Some
of these differences may be due to the physical and chemical
properties of the different fiber types. For example, several
studies suggest that amphibole asbestos types (tremolite,
amosite, and especially crocidolite) may be more harmful than
chrysotile, particularly for mesothelioma. Other data indicate
that fiber size dimensions (length and diameter) are important
factors for cancer-causing potential. Some data indicate that
fibers with lengths greater than 5.0 µm are more likely to
cause injury than fibers with lengths less than 2.5 µm. (1
µm is about 1/25,000 of an inch.) Additional data indicate
that short fibers can contribute to injury. This appears to
be true for mesothelioma, lung cancer, and asbestosis. However,
fibers thicker than 3.0 µm are of lesser concern, because
they have little chance of penetrating to the lower regions
of the lung.
The health effects from swallowing asbestos
are unclear. Some groups of people who have been exposed to
asbestos fibers in their drinking water have higher-than-average
death rates from cancer of the esophagus, stomach, and intestines.
However, it is very difficult to tell whether this is caused
by asbestos or by something else. Animals that were given
very high doses of asbestos in food did not get more fatal
cancers than usual, although some extra nonfatal tumors did
occur in the intestines of rats in one study.
Several government offices and regulatory
agencies have considered all of the evidence regarding the
carcinogenicity of asbestos. The Department of Health and
Human Services (DHHS) has determined that asbestos is known
to be a human carcinogen. The EPA has determined that asbestos
is a human carcinogen. The International Agency for Research
on Cancer (IARC) has determined that asbestos is carcinogenic
to humans. Please see the toxicological profile for more information
on how asbestos can affect your health.
How can asbestos affect children?
This section discusses potential health
effects from exposures during the period from conception to
maturity at 18 years of age in humans.
Asbestos exposure in both children and
adults may occur while breathing air in or near buildings
(public or private) containing asbestos building materials
or near asbestos-related industrial operations. Children breathe
differently and have different lung structures than adults.
It is not known if these differences may cause a greater amount
of asbestos fibers to stay in the lungs of a child when they
are breathed in than in the lungs of an adult. Children drink
more fluids per kilogram of body weight than adults and can
also be exposed through asbestos-contaminated drinking water.
Eating asbestos-contaminated soil and dust is another source
of exposure for children. Certain children intentionally eat
soil, and all young children eat more soil than adults through
hand-to-mouth activities. Historically, family members have
also been exposed to asbestos that was carried home on the
clothing of other family members who worked in asbestos mines
or mills. Breathing of asbestos fibers may result in difficulty
in breathing, lung cancer, or mesothelioma (another form of
cancer associated with asbestos exposure). These diseases
usually appear many years following the first exposure to
asbestos and are therefore not likely to be seen in children.
But since it may take up to 40 or more years for the effects
of exposure to be seen, people who have been exposed to asbestos
at a young age may be more likely to contract these diseases
than those who are first exposed later in life. In the small
number of studies that have specifically looked at asbestos
exposure in children, there is no indication that younger
people might develop asbestos-related diseases more quickly
than older people. Developing fetuses and infants are not
likely to be exposed to asbestos through the placenta or breast
milk of the mother. Results of animal studies do not indicate
that exposure to asbestos is likely to result in birth defects.
How can families reduce the risk of exposure to asbestos?
If your doctor finds that you have been
exposed to significant amounts of asbestos, ask whether your
children might also be exposed. Your doctor might need to
ask your state health department to investigate.
The most important way that families
can lower their exposures to asbestos is to be aware of the
sources of asbestos in their homes and avoid exposure to these
sources. The most important source of asbestos in a home is
from damaged or deteriorating asbestos-containing insulation,
ceiling, or floor tiles. Should you suspect that your house
may contain asbestos, contact your state or local health department
or the regional offices of EPA to find out how to test your
home for asbestos and how to locate a company that is trained
to remove or contain the fibers. Federal law requires schools
to identify asbestos-containing material in school buildings
and take appropriate action to control release of asbestos
If you live close to where asbestos and
certain other ores are mined or processed, where a building
that contains asbestos products is being torn down or renovated,
or a waste site where asbestos is not properly covered, then
the levels of asbestos in dust and wind-blown soil may be
higher. Pets can also bring asbestos into the home by carrying
dust or dirt on their fur or feet if they spend time in places
that have high levels of asbestos in the soil. Swallowing
of asbestos in house dust or soil is a potential exposure
pathway for children. This problem can be reduced in many
ways. Regular hand and face washing to remove asbestos-containing
dusts and soil, especially before meals, can lower the possibility
of asbestos fibers on the skin being accidentally swallowed
while eating. Families can lower exposures to asbestos by
regularly cleaning the home of dust and tracked in soil. Door
mats can help lower the amount of soil that is tracked into
the home; removing your shoes before entering will also help.
Planting grass and shrubs over bare soil areas in the yard
can lower the contact that children and pets may have with
soil and reduce the tracking of soil into the home.
You can bring asbestos home in the dust
on your hands or clothes if you work in the mining or processing
of minerals that contain asbestos, in asbestos removal, or
in buildings with damaged or deteriorating asbestos. Federal
law regulates work practices to limit the possibility of asbestos
being brought home in this way. Your occupational health and
safety officer at work can and should tell you whether chemicals
you work with are dangerous and likely to be carried home
on your clothes, body, or tools, and whether you should be
showering and changing clothes before you leave work, storing
your street clothes in a separate area of the workplace, or
laundering your work clothes at home separately from other
clothes. Your employer should have Material Safety Data Sheets
(MSDSs) for many of the chemicals used at your place of work,
as required by the Occupational Safety and Health Administration
(OSHA). Information on these sheets should include chemical
names and hazardous ingredients, important properties (such
as fire and explosion data), potential health effects, how
you get the chemical(s) in your body, how to handle the materials
properly, and what to do in an emergency. Your employer is
legally responsible for providing a safe workplace and should
freely answer your questions about hazardous chemicals. Either
OSHA or your OSHA-approved state occupational safety and health
program can answer any further questions and help your employer
identify and correct problems with hazardous substances. OSHA and/or your OSHA-approved state occupational safety and health
program will listen to your formal complaints about workplace
health hazards and inspect your workplace when necessary.
Employees have a right to seek safety and health on the job
without fear of punishment.
Is there a medical test to determine whether I have been exposed to asbestos?
The most common test used to determine
if you have received sustained exposure to asbestos is a chest
x-ray. A chest x-ray is recommended for detecting exposure
to asbestos only in persons who have sustained relatively
heavy exposure. A chest x-ray is of no value for detecting
evidence of asbestos exposure in a person whose exposure to
asbestos has been only brief or transient. The x-ray cannot
detect the asbestos fibers themselves, but it can detect early
signs of lung disease caused by asbestos. While other substances
besides asbestos can sometimes produce similar changes in
the lungs, this test is usually reliable for detecting asbestos-related
effects produced by long-term exposures at relatively high
concentrations of asbestos fibers. Other tests, such as gallium-67
lung scanning and high-resolution computed tomography, are
also useful in detecting changes in the lungs. However, there
are currently no means of detecting exposure-related effects
from commonly encountered environmental exposures.
The most reliable test to determine if
you have been exposed to asbestos is the detection of microscopic
asbestos fibers in pieces of lung tissue removed by surgery,
but this is a very invasive test. A test can also be run to
determine the presence of asbestos fibers in material rinsed
out of the lung. However, this test can cause some discomfort.
Asbestos fibers can also be detected in mucus (sputum), urine,
or feces, but these tests are not reliable for determining
how much asbestos may be in your lungs. Low levels of asbestos
fibers are found in these materials for nearly all people.
Higher-than-average levels can show that you have been exposed
to asbestos, but it is not yet possible to use the results
of this test to estimate how much asbestos you have been exposed
to, or to predict whether you are likely to suffer any health
effects. Please see the toxicological profile for more information
about how asbestos can be measured in people and in the environment.
What recommendations has the federal government made to protect human health?
The federal government develops regulations
and recommendations to protect public health. Regulations can be enforced by law. Federal agencies that develop
regulations for toxic substances include the Environmental
Protection Agency (EPA), the Occupational Safety and Health
Administration (OSHA), and the Food and Drug Administration
(FDA). Recommendations provide valuable guidelines to protect
public health but cannot be enforced by law. Federal
organizations that develop recommendations for toxic substances
include the Agency for Toxic Substances and Disease Registry
(ATSDR) and the National Institute for Occupational Safety
and Health (NIOSH).
Regulations and recommendations can be
expressed in not-to-exceed levels in air, water, soil, or
food that are usually based on levels that affect animals;
then they are adjusted to help protect people. Sometimes these
not-to-exceed levels differ among federal organizations because
of different exposure times (an 8-hour workday or a 24-hour
day), the use of different animal studies, or other factors.
Recommendations and regulations are also
periodically updated as more information becomes available.
For the most current information, check with the federal agency
or organization that provides it. Some regulations and recommendations
for asbestos include the following:
The federal government has taken a number
of steps to protect citizens from exposure to asbestos. First,
on July 12, 1989, EPA established a ban on new uses of asbestos.
Uses established before this date are still allowable. Second,
EPA has established regulations that require school systems
to inspect for asbestos and, if damaged asbestos is found,
to eliminate or reduce the exposure, either by removing the
asbestos or by covering it up so it cannot get into the air.
In addition, EPA provides guidance and support for reducing
asbestos exposure in other public buildings. Third, EPA regulates
the release of asbestos from factories and during building
demolition or renovation to prevent asbestos from getting
into the environment. EPA also regulates the disposal of waste
asbestos materials or products, requiring these to be placed
only in approved locations. Fourth, EPA has proposed a limit
of 7 million fibers per liter on the concentration of long
fibers (length greater than or equal to 5 µm) that may be
present in drinking water. Fifth, FDA regulates the use of
asbestos in the preparation of drugs and restricts the use
of asbestos in food-packaging materials. NIOSH has recommended
that inhalation exposures not exceed 100,000 fibers with lengths
greater than or equal to 5 µm per m3 of air (0.1 fibers/mL).
OSHA has established an enforceable limit on the average 8-hour
daily concentration of asbestos allowed in air in the workplace
to be 100,000 fibers with lengths greater than or equal to
5 µm per m3 of air (0.1 fibers/mL). Additional sources
of information about asbestos are the 10 regional offices
of the EPA. Most EPA regional offices have an asbestos coordinator.
Please see the toxicological profile
for more information about regulations and guidelines to protect
people from exposure to asbestos.
Agency for Toxic Substances and Disease Registry (ATSDR). 2001. Toxicological profile for Asbestos. Atlanta, GA: U.S. Department of Health and Human Services, Public Health Service.
Where can I get more information?
If you have questions or concerns, please contact your community or state health or environmental quality department or:
For more information, contact:
Agency for Toxic Substances and Disease Registry
Division of Toxicology and Human Health Sciences
4770 Buford Highway
Chamblee, GA 30341-3717
Phone: 1-800-CDC-INFO 888-232-6348 (TTY)
Email: Contact CDC-INFO
ATSDR can also tell you the location of occupational and environmental health clinics. These clinics specialize in recognizing, evaluating, and treating illnesses resulting from exposure to hazardous substances.