July 1999 |
ToxFAQs™ |
for |
Chlorobenzene |
(Clorobenceno) |
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This fact sheet answers the most frequently
asked health questions about chlorobenzene. 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: Chlorobenzene is
used as a solvent for some pesticide formulations, as
a degreaser, and to make other chemicals. High levels
of chlorobenzene can damage the liver and kidneys and
affect the brain. It has been found at 97 of the 1,177
National Priorities List sites identified by the Environmental
Protection Agency (EPA). |
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What
is chlorobenzene? |
Chlorobenzene is a colorless, flammable
liquid with an aromatic, almond-like odor. Some of it will
dissolve in water, but it readily evaporates into air. It
does not occur naturally in the environment.
Chlorobenzene production in the United
States has declined by more than 60% from its peak in 1960.
It was used in the past to make other chemicals, such as phenol
and DDT. Now chlorobenzene is used as a solvent for some pesticide
formulations, to degrease automobile parts, and as a chemical
intermediate to make several other chemicals.
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What
happens to chlorobenzene when it enters the environment? |
- Chlorobenzene released to air is slowly broken down by
reactions with other chemicals and sunlight or can be removed
by rain.
- In water, chlorobenzene will rapidly evaporate to the
air and/or be broken down by bacteria.
- When released to soil, it is broken down rapidly by bacteria,
but some will evaporate to the air and some may filter into
the groundwater.
- Chlorobenzene does not build up in the food chain.
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How
might I be exposed to chlorobenzene? |
- If you work where chlorobenzene is made or used you could
be exposed by breathing air with chlorobenzene vapors or
by spilling or splashing chlorobenzene on your skin.
- People that live near a waste site containing chlorobenzene
could be exposed by drinking contaminated groundwater, breathing
vapors released to the air, or getting contaminated soil
on their skin.
- You could be exposed by eating food contaminated with
chlorobenzene but there is not enough information to determine
how often this occurs.
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How
can chlorobenzene affect my health? |
Workers exposed to high levels of chlorobenzene
in the air complained of headaches, nausea, sleepiness, numbness,
and vomiting. We cannot be certain that all of these effects
were due to chlorobenzene exposure because the workers may
have been exposed to other chemicals.
Animal studies indicate that the liver,
kidney, and central nervous system are affected by exposure
to chlorobenzene. Effects on the central nervous system from
breathing chlorobenzene include unconsciousness, tremors,
restlessness, and death. Longer exposure has caused liver
and kidney damage. The limited data available indicate that
chlorobenzene does not cause birth defects or infertility.
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How
likely is chlorobenzene to cause cancer? |
It is not known whether chlorobenzene
causes cancer in people. Although chlorobenzene did not produce
cancer in animal studies with rats and mice, liver nodules
which can lead to cancer were produced in male rats. The EPA
has determined that chlorobenzene is not classifiable as to
human carcinogenicity based on inadequate evidence in both
humans and animals.
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Is
there a medical test to show whether I've been exposed to chlorobenzene? |
Exposure to chlorobenzene can be determined
by measuring it or its metabolites in urine, exhaled air,
blood, and body fat, but these tests cannot be used to predict
whether harmful health effects will occur. These tests are
not usually done in the doctors' office because special equipment
is needed.
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Has the federal government made recommendations to protect human health? |
The EPA has set a Maximum Contaminant
Level (MCL) of 0.1 parts per million (0.1 ppm) for chlorobenzene
in drinking water. Concentrations in drinking water for short-term
exposures (up to 10 days) should not exceed 2 ppm. The EPA
recommends that levels of chlorinated benzenes (a group of
chemicals that includes chlorobenzene) in lakes and streams
should be limited to 0.488 ppm to prevent possible health
effects from drinking water or eating fish contaminated with
this group of chemicals. Any release to the environment greater
than 100 pounds of chlorobenzene must be reported to the EPA.
The Occupational Safety and Health Administration
(OSHA) has set a workplace air concentration limit of 75 ppm
over an 8-hour workday, 40-hour workweek.
The federal recomendations have been
updated as of July 1999.
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Glossary |
Carcinogenicity: Ability to cause cancer.
CAS: Chemical Abstracts Service.
Evaporate: To change into a vapor or
a gas.
National Priorities List: A list of the
nation's worst hazardous waste sites.
Pesticide: A substance that kills pests.
ppm: Parts per million.
Solvent: A substance that dissolves another
substance.
Tremor: Trembling or shaking caused by
disease or stress.
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References |
Agency for Toxic Substances and Disease
Registry (ATSDR). 1990. Toxicological Profile for chlorobenzene. 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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