Pendedahan Asbestos dan Risiko Kanser
ruj: http://www.cancer.gov/cancertopics/factsheet/Risk/asbestos
Asbestos Exposure and Cancer Risk
Key Points
- Asbestos
is the name given to a group of minerals that occur naturally in the
environment as bundles of fibers.
- Exposure
to asbestos may increase the risk of asbestosis, other nonmalignant lung
and pleural disorders, lung cancer, mesothelioma, and other cancers.
- Smokers
who are also exposed to asbestos have a greatly increased risk of lung
cancer.
- Individuals
who have been exposed (or suspect they have been exposed) to asbestos on
the job, through the environment, or at home through a family contact
should inform their physician and report any symptoms.
- Government
agencies can provide additional information on asbestos exposure.
- What
is asbestos?
Asbestos is the name given to a group of minerals
that occur naturally in the environment as bundles of fibers that can be
separated into thin, durable threads. These fibers are resistant to heat, fire,
and chemicals and do not conduct electricity. For these reasons, asbestos has
been used widely in many industries.
Chemically, asbestos minerals are silicate
compounds, meaning they contain atoms of silicon and oxygen in their molecular
structure.
Asbestos minerals are divided into two major
groups: Serpentine asbestos and amphibole asbestos. Serpentine asbestos
includes the mineral chrysotile, which has long, curly fibers that can be
woven. Chrysotile asbestos is the form that has been used most widely in
commercial applications. Amphibole asbestos includes the minerals actinolite,
tremolite, anthophyllite, crocidolite, and amosite. Amphibole asbestos has
straight, needle-like fibers that are more brittle than those of serpentine
asbestos and are more limited in their ability to be fabricated (1, 2).
- How
is asbestos used?
Asbestos has been mined and used commercially in
North America since the late 1800s. Its use increased greatly during World War
II (3, 4). Since then, asbestos has been used in many
industries. For example, the building and construction industries have used it
for strengthening cement and plastics as well as for insulation, roofing,
fireproofing, and sound absorption. The shipbuilding industry has used asbestos
to insulate boilers, steam pipes, and hot water pipes. The automotive industry
uses asbestos in vehicle brake shoes and clutch pads. Asbestos has also been
used in ceiling and floor tiles; paints, coatings, and adhesives; and plastics.
In addition, asbestos has been found in vermiculite-containing garden products
and some talc-containing crayons.
In the late 1970s, the U.S. Consumer Product Safety
Commission (CPSC) banned the use of asbestos in wallboard patching compounds
and gas fireplaces because the asbestos fibers in these products could be
released into the environment during use. In addition, manufacturers of
electric hairdryers voluntarily stopped using asbestos in their products in
1979. In 1989, the U.S. Environmental Protection Agency (EPA) banned all new
uses of asbestos; however, uses developed before 1989 are still allowed. The
EPA also established regulations that require school systems to inspect
buildings for the presence of damaged asbestos and to eliminate or reduce
asbestos exposure to occupants by removing the asbestos or encasing it (2).
In June 2000, the CPSC concluded that the risk of
children’s exposure to asbestos fibers in crayons was extremely low (1). However, U.S. manufacturers of these crayons
agreed to eliminate talc from their products.
In August 2000, the EPA conducted a series of tests
to evaluate the risk for consumers of adverse health effects associated with
exposure to asbestos-contaminated vermiculite. The EPA concluded that exposure
to asbestos from some vermiculite products poses only a minimal health risk.
The EPA recommended that consumers reduce the low risk associated with the
occasional use of vermiculite during gardening activities by limiting the
amount of dust produced during vermiculite use. Specifically, the EPA suggested
that consumers use vermiculite outdoors or in a well-ventilated area; keep
vermiculite damp while using it; avoid bringing dust from vermiculite into the
home on clothing; and use premixed potting soil, which is less likely to
generate dust (2).
The regulations described above and other actions,
coupled with widespread public concern about the health hazards of asbestos,
have resulted in a significant annual decline in the U.S. use of asbestos.
Domestic consumption of asbestos amounted to about 803,000 metric tons in 1973,
but it had dropped to about 2,400 metric tons by 2005 (3, 5).
- What
are the health hazards of exposure to asbestos?
People may be exposed to asbestos in their
workplace, their communities, or their homes. If products containing asbestos
are disturbed, tiny asbestos fibers are released into the air. When asbestos
fibers are breathed in, they may get trapped in the lungs and remain there for
a long time. Over time, these fibers can accumulate and cause scarring and inflammation, which can affect breathing and lead
to serious health problems (6).
Asbestos has been classified as a known human
carcinogen (a substance that causes cancer) by the U.S. Department of Health
and Human Services, the EPA, and the International Agency for Research on
Cancer (2, 3, 7, 8). Studies have shown that exposure to asbestos
may increase the risk of lung cancer and mesothelioma (a relatively rare cancer
of the thin membranes that line the chest and abdomen). Although rare, mesothelioma is the most
common form of cancer associated with asbestos exposure. In addition to lung
cancer and mesothelioma, some studies have suggested an association between
asbestos exposure and gastrointestinal and colorectal cancers, as well as an elevated risk
for cancers of the throat, kidney, esophagus, and gallbladder (3, 4). However, the evidence is inconclusive.
Asbestos exposure may also increase the risk of
asbestosis (an inflammatory condition affecting the lungs that can cause
shortness of breath, coughing, and permanent lung damage) and other
nonmalignant lung and pleural disorders, including pleural plaques (changes in
the membranes surrounding the lung), pleural thickening, and benign pleural effusions (abnormal collections of fluid between the thin layers of tissue lining the lungs and the wall of the chest
cavity). Although pleural plaques are not precursors to lung cancer, evidence
suggests that people with pleural disease caused by exposure to asbestos may be
at increased risk for lung cancer (2, 9).
- Who
is at risk for an asbestos-related disease?
Everyone is exposed to asbestos at some time during
their life. Low levels of asbestos are present in the air, water, and soil.
However, most people do not become ill from their exposure. People who become
ill from asbestos are usually those who are exposed to it on a regular basis,
most often in a job where they work directly with the material or through
substantial environmental contact.
Since the early 1940s, millions of American workers
have been exposed to asbestos. Health hazards from asbestos fibers have been
recognized in workers exposed in the shipbuilding trades, asbestos mining and
milling, manufacturing of asbestos textiles and other asbestos products,
insulation work in the construction and building trades, and a variety of other
trades. Demolition workers, drywall removers, asbestos removal workers,
firefighters, and automobile workers also may be exposed to asbestos fibers.
Studies evaluating the cancer risk experienced by automobile mechanics exposed
to asbestos through brake repair are limited, but the overall evidence suggests
there is no safe level of asbestos exposure (3, 8). As a result of Government regulations and
improved work practices, today’s workers (those without previous exposure) are
likely to face smaller risks than did those exposed in the past.
Individuals involved in the rescue, recovery, and
cleanup at the site of the September 11, 2001, attacks on the World Trade
Center (WTC) in New York City are another group at risk of developing an
asbestos-related disease. Because asbestos was used in the construction of the
North Tower of the WTC, when the building was attacked, hundreds of tons of
asbestos were released into the atmosphere. Those at greatest risk include
firefighters, police officers, paramedics, construction workers, and volunteers
who worked in the rubble at Ground Zero. Others at risk include residents in
close proximity to the WTC towers and those who attended schools nearby. These
individuals will need to be followed to determine the long-term health
consequences of their exposure (10).
One study found that nearly 70 percent of WTC
rescue and recovery workers suffered new or worsened respiratory symptoms while
performing work at the WTC site. The study describes the results of the WTC
Worker and Volunteer Medical Screening Program, which was established to
identify and characterize possible WTC-related health effects in responders.
The study found that about 28 percent of those tested had abnormal lung
function tests, and 61 percent of those without previous health problems
developed respiratory symptoms (11). However, it is important to note that these
symptoms may be related to exposure to debris components other than asbestos.
Although it is clear that the health risks from
asbestos exposure increase with heavier exposure and longer exposure time,
investigators have found asbestos-related diseases in individuals with only
brief exposures. Generally, those who develop asbestos-related diseases show no
signs of illness for a long time after their first exposure. It can take from
10 to 40 years or more for symptoms of an asbestos-related condition to appear
(2).
There is some evidence that family members of
workers heavily exposed to asbestos face an increased risk of developing
mesothelioma (6). This risk is thought to result from exposure
to asbestos fibers brought into the home on the shoes, clothing, skin, and hair
of workers. To decrease these exposures, Federal law regulates workplace
practices to limit the possibility of asbestos being brought home in this way.
Some employees may be required to shower and change their clothes before they
leave work, store their street clothes in a separate area of the workplace, or
wash their work clothes at home separately from other clothes (2).
Cases of mesothelioma have also been seen in
individuals without occupational asbestos exposure who live close to asbestos
mines (6).
- What
factors affect the risk of developing an asbestos-related disease?
Several factors can help to determine how asbestos
exposure affects an individual, including (2, 6):
- Dose
(how much asbestos an individual was exposed to).
- Duration
(how long an individual was exposed).
- Size,
shape, and chemical makeup of the asbestos fibers.
- Source
of the exposure.
- Individual
risk factors, such as smoking and
pre-existing lung disease.
Although all forms of asbestos are considered
hazardous, different types of asbestos fibers may be associated with different
health risks. For example, the results of several studies suggest that amphibole
forms of asbestos may be more harmful than chrysotile, particularly for
mesothelioma risk, because they tend to stay in the lungs for a longer period
of time (1, 2).
- How
does smoking affect risk?
Many studies have shown that the combination of
smoking and asbestos exposure is particularly hazardous. Smokers who are also
exposed to asbestos have a risk of developing lung cancer that is greater than
the individual risks from asbestos and smoking added together (3, 6). There is evidence that quitting smoking will
reduce the risk of lung cancer among asbestos-exposed workers (4). Smoking combined with asbestos exposure does
not appear to increase the risk of mesothelioma (9). However, people who were exposed to asbestos
on the job at any time during their life or who suspect they may have been
exposed should not smoke.
- How
are asbestos-related diseases detected?
Individuals who have been exposed (or suspect they
have been exposed) to asbestos fibers on the job, through the environment, or
at home via a family contact should inform their doctor about their exposure
history and whether or not they experience any symptoms. The symptoms of
asbestos-related diseases may not become apparent for many decades after the
exposure. It is particularly important to check with a doctor if any of the
following symptoms develop (6):
A thorough physical examination, including a chest x-ray and lung function tests, may be
recommended. The chest x-ray is currently the most common tool used to detect
asbestos-related diseases. However, it is important to note that chest x-rays
cannot detect asbestos fibers in the lungs, but they can help identify any
early signs of lung disease resulting from asbestos exposure (2).
Studies have shown that computed tomography (CT) (a series of detailed pictures of areas
inside the body taken from different angles; the pictures are created by a
computer linked to an x-ray machine) may be more effective than conventional
chest x-rays at detecting asbestos-related lung abnormalities in individuals
who have been exposed to asbestos (12).
A lung biopsy, which detects microscopic asbestos fibers in pieces of lung
tissue removed by surgery, is the most reliable test to confirm the
presence of asbestos-related abnormalities. A bronchoscopy is a less invasive test than a
biopsy and detects asbestos fibers in material that is rinsed out of the lungs.
It is important to note that these tests cannot determine how much asbestos an
individual may have been exposed to or whether disease will develop (12). Asbestos fibers can also be detected in
urine, mucus, or feces, but these tests are not reliable for determining how
much asbestos may be in an individual’s lungs (2).
- How
can workers protect themselves from asbestos exposure?
The Occupational Safety and Health
Administration (OSHA) is a component of the U.S. Department of Labor (DOL)
and is the Federal agency responsible for health and safety regulations in maritime,
construction, manufacturing, and service workplaces. OSHA established
regulations dealing with asbestos exposure on the job, specifically in
construction work, shipyards, and general industry, that employers are required
to follow. In addition, the Mine Safety and Health Administration (MSHA),
another component of the DOL, enforces regulations related to mine safety.
Workers should use all protective equipment provided by their employers and
follow recommended workplace practices and safety procedures. For example,
National Institute for Occupational Safety and Health (NIOSH)-approved
respirators that fit properly should be worn by workers when required.
Workers who are concerned about asbestos exposure
in the workplace should discuss the situation with other employees, their
employee health and safety representative, and their employers. If necessary,
OSHA can provide more information or make an inspection. Regional offices of
OSHA are listed in the “United States Government” section of a telephone directory’s
blue pages (under “Department of Labor”). Regional offices can also be found at
http://www.osha.gov/html/RAmap.html.
More information about asbestos is available on the
OSHA Asbestos Web page, which has links to information about asbestos in the
workplace, including what OSHA standards apply, the hazards of asbestos,
evaluating asbestos exposure, and controls used to protect workers. This page
is available at http://www.osha.gov/SLTC/asbestos/index.html.
OSHA’s national office can be contacted at:
Office of Public Affairs
Occupational Safety and Health Administration
U.S. Department of Labor
Room N–3649
200 Constitution Avenue, NW.
Washington, DC 20210
202–693–1999
1–800–321–6742 (1–800–321–OSHA)
1–877–889–5627 (TTY)
http://www.osha.gov/workers.html (workers’ page)
Occupational Safety and Health Administration
U.S. Department of Labor
Room N–3649
200 Constitution Avenue, NW.
Washington, DC 20210
202–693–1999
1–800–321–6742 (1–800–321–OSHA)
1–877–889–5627 (TTY)
http://www.osha.gov/workers.html (workers’ page)
Mine workers can contact MSHA at:
Office of Public Affairs
Mine Safety and Health Administration
U.S. Department of Labor
21st Floor
1100 Wilson Boulevard
Arlington, VA 22209
202–693–9400
1–800–746–1553
http://www.msha.gov
http://www.msha.gov/codeaphone/codeaphonenew.htm (National Hazard Reporting Page)
Mine Safety and Health Administration
U.S. Department of Labor
21st Floor
1100 Wilson Boulevard
Arlington, VA 22209
202–693–9400
1–800–746–1553
http://www.msha.gov
http://www.msha.gov/codeaphone/codeaphonenew.htm (National Hazard Reporting Page)
The National Institute for Occupational Safety and
Health (NIOSH), which is part of the Centers for Disease Control and Prevention (CDC),
is another Federal agency that is concerned with asbestos exposure in the
workplace. NIOSH conducts asbestos-related research, evaluates work sites for
possible health hazards, and makes exposure control recommendations. In
addition, NIOSH distributes publications on the health effects of asbestos exposure
and can suggest additional sources of information. NIOSH can be contacted at:
Education and Information Division
Information Resources Branch
National Institute for Occupational Safety and Health
4676 Columbia Parkway
Cincinnati, OH 45226
1–800–CDC–INFO (1–800–232–7636)
cdcinfo@cdc.gov
http://www.cdc.gov/niosh
Information Resources Branch
National Institute for Occupational Safety and Health
4676 Columbia Parkway
Cincinnati, OH 45226
1–800–CDC–INFO (1–800–232–7636)
cdcinfo@cdc.gov
http://www.cdc.gov/niosh
- What
programs are available to help individuals with asbestos-related diseases?
Some people with asbestos-related illness may be
eligible for Medicare coverage. Information about benefits is available
from Medicare’s Regional Offices, located in 10 major cities across the United
States and serving specific geographic areas. The Regional Offices serve as the
agency’s initial point of contact for beneficiaries, health care providers,
state and local governments, and the general public. Contact information for
each Regional Office can be found at http://www.cms.hhs.gov/regionaloffices.
General information about Medicare is available by calling toll-free
1–800–633–4227 (1–800–MEDICARE) or visiting http://www.medicare.gov.
People with occupational asbestos-related diseases
also may qualify for financial help, including medical payments, under state
workers’ compensation laws. Because eligibility requirements vary from state to
state, workers employed by private companies or by state and local government
agencies should contact their state workers’ compensation board. Contact
information for state workers’ compensation officials may be found in the blue
pages of a local telephone directory or at http://www.dol.gov/owcp/owcpkeyp.htm.
If exposure occurred during employment with a
Federal agency, medical expenses and other compensation may be covered by the Federal
Employees’ Compensation Program, which is administered by the DOL, Employment
Standards Administration’s Office of Workers’ Compensation Programs. This
program provides workers’ compensation benefits to Federal (civilian) employees
for employment-related injuries and diseases. Benefits include wage
replacement, payment for medical care, and, where necessary, medical and vocational
rehabilitation assistance in returning to work.
Benefits may also be provided to dependents if the injury or disease causes the
employee’s death. The program has 12 district offices nationwide.
In addition, the Longshore and Harbor Workers’
Compensation Program provides benefits to longshoremen, harbor workers,
other maritime workers, and other classes of private industry workers who are
injured during the course of employment or suffer from diseases caused or
worsened by conditions of employment. Information about eligibility and how to
file a claim for benefits under either of these programs is available from:
Office of Workers’ Compensation Programs
Employment Standards Administration
U.S. Department of Labor
Frances Perkins Building
200 Constitution Avenue, NW.
Washington, DC 20210
1–866–692–7487 (1–866–OWCPIVR)
202–693–0040 (Federal Employees’ Compensation Program)
202–693–0038 (Longshore and Harbor Workers’ Compensation Program)
OWCP-Public@dol.gov
http://www.dol.gov/owcp
Employment Standards Administration
U.S. Department of Labor
Frances Perkins Building
200 Constitution Avenue, NW.
Washington, DC 20210
1–866–692–7487 (1–866–OWCPIVR)
202–693–0040 (Federal Employees’ Compensation Program)
202–693–0038 (Longshore and Harbor Workers’ Compensation Program)
OWCP-Public@dol.gov
http://www.dol.gov/owcp
Eligible veterans may receive health care at a Department
of Veterans Affairs (VA) Medical Center for an asbestos-related disease.
Veterans can receive treatment for service-connected and nonservice-connected
medical conditions. Information about eligibility and benefits is available
from the VA Health Benefits Service Center at 1–877–222–8387 (1–877–222–VETS)
or on the VA Web site at http://www1.va.gov/health/index.asp.
- Is
there Federal legislation to help victims of asbestos-related diseases?
No Federal legislation has been enacted to
compensate victims of asbestos-related diseases or to protect people from
asbestos exposure. However, a bill called the Fairness in Asbestos Injury
Resolution Act, or FAIR Act, has been introduced in Congress several times.
This bill would create a national trust fund to compensate victims suffering
from asbestos-related diseases. The proposed trust fund would be administered
by the DOL, outside of the courts, through a claims process in which all
individuals with certain medical symptoms and evidence of asbestos-related
disease would be compensated. Funding for the trust would come from insurance
companies and companies that mined, manufactured, and sold asbestos or asbestos
products. Under the bill, individuals affected by asbestos exposure would no
longer be able to pursue awards for damages in any Federal or state court.
- What
other organizations offer information related to asbestos exposure?
The organizations listed below can provide more
information about asbestos exposure.
The Agency for Toxic Substances and Disease
Registry (ATSDR) is the principal Federal agency responsible for evaluating
the human health effects of exposure to hazardous substances. This agency works
in close collaboration with local, state, and other Federal agencies, with tribal
governments, and with communities and local health care providers to help
prevent or reduce harmful human health effects from exposure to hazardous
substances. The ATSDR provides information about asbestos and where to find
occupational and environmental health clinics. The ATSDR can be contacted at:
Agency for Toxic Substances and Disease Registry
4770 Buford Highway, NE.
Atlanta, GA 30341
1–800–232–4636 (1–800–CDC–INFO)
1–888–232–6348 (TTY)
cdcinfo@cdc.gov
http://www.atsdr.cdc.gov
4770 Buford Highway, NE.
Atlanta, GA 30341
1–800–232–4636 (1–800–CDC–INFO)
1–888–232–6348 (TTY)
cdcinfo@cdc.gov
http://www.atsdr.cdc.gov
The U.S. Environmental Protection Agency (EPA)
regulates the general public’s exposure to asbestos in buildings, drinking
water, and the environment. The EPA offers a Toxic Substances Control Act
(TSCA) Hotline and an Asbestos Ombudsman. The TSCA Hotline provides technical
assistance and information about asbestos programs implemented under the TSCA,
which include the Asbestos School Hazard Abatement Act and the Asbestos Hazard
Emergency Response Act. The Asbestos Ombudsman focuses on asbestos in schools
and handles questions and complaints. Both the TSCA Hotline and the Asbestos
Ombudsman can provide publications on a number of topics, particularly on
controlling asbestos exposure in schools and other buildings. The Ombudsman
operates a toll-free hotline for small businesses, trade associations, and
others seeking free, confidential help.
The EPA Web site includes a list of EPA regional
and state asbestos contacts at http://www.epa.gov/asbestos/pubs/regioncontact.html.
In addition, EPA’s Asbestos and Vermiculite home page provides information
about asbestos and its health effects and links to asbestos resources,
including suggestions for homeowners who suspect asbestos in their homes, and
laws and regulations applicable to asbestos. This page can be found at http://www.epa.gov/asbestos.
Questions may be directed to:
U.S. Environmental Protection Agency
EPA West Building
National Program Chemicals Division
Mail Code 7404T
1200 Pennsylvania Avenue, NW.
Washington, DC 20460
202–554–1404 (TSCA Hotline)
202–554–0551 (TTY)
1–800–368–5888 (Asbestos Ombudsman)
tsca-hotline@epa.gov
http://www.epa.gov/asbestos
EPA West Building
National Program Chemicals Division
Mail Code 7404T
1200 Pennsylvania Avenue, NW.
Washington, DC 20460
202–554–1404 (TSCA Hotline)
202–554–0551 (TTY)
1–800–368–5888 (Asbestos Ombudsman)
tsca-hotline@epa.gov
http://www.epa.gov/asbestos
Another EPA resource that may be of interest is the
brochure titled Current Best Practices for Preventing Asbestos Exposure
Among Brake and Clutch Repair Workers. Released in April 2007, this
brochure includes work practices for both automotive professionals and home
mechanics that may be used to avoid asbestos exposure. It also summarizes
existing OSHA regulatory requirements for professional auto mechanics. The
brochure can be found at http://www.epa.gov/asbestos/pubs/brakesbrochure.html.
The U.S. Consumer Product Safety Commission
(CPSC) is responsible for protecting the public from unreasonable risks of
serious injury or death from more than 15,000 types of consumer products,
including asbestos, under the agency’s jurisdiction. The CPSC maintains a
toll-free 24-hour hotline where callers can obtain product safety and other
agency information and report unsafe products. In addition, CPSC publications
provide guidelines for repairing and removing asbestos, and general information
about asbestos in the home. CPSC can be contacted at:
Office of Information and Public Affairs
U.S. Consumer Product Safety Commission
4330 East West Highway
Bethesda, MD 20814
1–800–638–2772
1–800–638–8270 (TTY)
http://www.cpsc.gov
U.S. Consumer Product Safety Commission
4330 East West Highway
Bethesda, MD 20814
1–800–638–2772
1–800–638–8270 (TTY)
http://www.cpsc.gov
Individuals can also contact their local or state health
department with questions or concerns about asbestos.
Tiada ulasan:
Catat Ulasan
Nota: Hanya ahli blog ini sahaja yang boleh mencatat ulasan.