September 1997 |
ToxFAQs™ |
for |
Benzene |
(Benceno) |
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This fact sheet answers the most frequently
asked health questions about benzene. For more information,
you may call the ATSDR Information Center at 1-888-422-8737.
This fact sheet is one in a series of summaries about hazardous
substances and their health effects. 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.
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HIGHLIGHTS: Benzene is a widely
used chemical formed from both natural processes and human
activities. Breathing benzene can cause drowsiness, dizziness,
and unconsciousness; long-term benzene exposure causes
effects on the bone marrow and can cause anemia and leukemia.
Benzene has been found in at least 813 of the 1,430 National
Priorities List sites identified by the Environmental
Protection Agency (EPA). |
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What
is benzene? |
Benzene is a colorless liquid with a
sweet odor. It evaporates into the air very quickly and dissolves
slightly in water. It is highly flammable and is formed from
both natural processes and human activities.
Benzene is widely used in the United
States; it ranks in the top 20 chemicals for production volume.
Some industries use benzene to make other chemicals which
are used to make plastics, resins, and nylon and synthetic
fibers. Benzene is also used to make some types of rubbers,
lubricants, dyes, detergents, drugs, and pesticides. Natural
sources of benzene include volcanoes and forest fires. Benzene
is also a natural part of crude oil, gasoline, and cigarette
smoke.
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What
happens to benzene when it enters the environment? |
- Industrial processes are the main source of benzene in
the environment.
- Benzene can pass into the air from water and soil.
- It reacts with other chemicals in the air and breaks down
within a few days.
- Benzene in the air can attach to rain or snow and be carried
back down to the ground.
- It breaks down more slowly in water and soil, and can
pass through the soil into underground water.
- Benzene does not build up in plants or animals.
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How
might I be exposed to benzene? |
- Outdoor air contains low levels of benzene from tobacco
smoke, automobile service stations, exhaust from motor vehicles,
and industrial emissions.
- Indoor air generally contains higher levels of benzene
from products that contain it such as glues, paints, furniture
wax, and detergents.
- Air around hazardous waste sites or gas stations will
contain higher levels of benzene.
- Leakage from underground storage tanks or from hazardous
waste sites containing benzene can result in benzene contamination
of well water.
- People working in industries that make or use benzene
may be exposed to the highest levels of it.
- A major source of benzene exposure is tobacco smoke.
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How
can benzene affect my health? |
Breathing very high levels of benzene
can result in death, while high levels can cause drowsiness,
dizziness, rapid heart rate, headaches, tremors, confusion,
and unconsciousness. Eating or drinking foods containing high
levels of benzene can cause vomiting, irritation of the stomach,
dizziness, sleepiness, convulsions, rapid heart rate, and
death.
The major effect of benzene from long-term
(365 days or longer) exposure is on the blood. Benzene causes
harmful effects on the bone marrow and can cause a decrease
in red blood cells leading to anemia. It can also cause excessive
bleeding and can affect the immune system, increasing the
chance for infection.
Some women who breathed high levels of
benzene for many months had irregular menstrual periods and
a decrease in the size of their ovaries. It is not known whether
benzene exposure affects the developing fetus in pregnant
women or fertility in men.
Animal studies have shown low birth weights,
delayed bone formation, and bone marrow damage when pregnant
animals breathed benzene.
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How
likely is benzene to cause cancer? |
The Department of Health and Human Services
(DHHS) has determined that benzene is a known human carcinogen.
Long-term exposure to high levels of benzene in the air can
cause leukemia, cancer of the blood-forming organs.
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Is
there a medical test to show whether I've been exposed to benzene? |
Several tests can show if you have been
exposed to benzene. There is test for measuring benzene in
the breath; this test must be done shortly after exposure.
Benzene can also be measured in the blood, however, since
benzene disappears rapidly from the blood, measurements are
accurate only for recent exposures.
In the body, benzene is converted to
products called metabolites. Certain metabolites can be measured
in the urine. However, this test must be done shortly after
exposure and is not a reliable indicator of how much benzene
you have been exposed to, since the metabolites may be present
in urine from other sources.
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Has the federal government made recommendations to protect human health? |
The EPA has set the maximum permissible
level of benzene in drinking water at 0.005 milligrams per
liter (0.005 mg/L). The EPA requires that spills or accidental
releases into the environment of 10 pounds or more of benzene
be reported to the EPA.
The Occupational Safety and Health Administration
(OSHA) has set a permissible exposure limit of 1 part of benzene
per million parts of air (1 ppm) in the workplace during
an 8-hour workday, 40-hour workweek.
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Glossary |
Anemia: Decreased ability of the blood
to transport oxygen.
Carcinogen: A substance with the ability
to cause cancer.
Chromosomes: Parts of the cells responsible
for the development of hereditary characteristics.
Metabolites: Breakdown products of chemicals.
Milligram (mg): One thousandth of a gram.
Pesticide: A substance that kills pests.
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References |
Agency for Toxic Substances and Disease
Registry (ATSDR). 1997. Managing Hazardous Materials Incidents.
Volume III Medical Management Guidelines for Acute
Chemical Exposures: Benzene. Atlanta,
GA: U.S. Department of Health and Human Services, Public Health
Service.
Agency for Toxic Substances and Disease
Registry (ATSDR). 1997. Toxicological
Profile for benzene. Atlanta, GA: U.S. Department of Health
and Human Services, Public Health Service.
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Where can I get more information? |
ATSDR can tell you where to find occupational
and environmental health clinics. Their specialists can recognize,
evaluate, and treat illnesses resulting from exposure to hazardous
substances. You can also contact your community or state health
or environmental quality department if you have any more questions
or concerns. For more information, contact:
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Agency for Toxic Substances and Disease Registry
Division of Toxicology
1600 Clifton Road NE, Mailstop F-32
Atlanta, GA 30333
Phone: 1-888-42-ATSDR (1-888-422-8737)
FAX: (770)-488-4178
Email: ATSDRIC@cdc.gov
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