1.1 What is chlorobenzene? |
1.2 How might I be exposed to chlorobenzene? |
1.3 How can chlorobenzene enter and leave
my body? |
1.4 How can chlorobenzene affect my health? |
1.5 What levels of exposure have resulted
in harmful effects? |
1.6 Is there a medical test to determine
whether I have been exposed to chlorobenzene? |
1.7 What recommendations has the federal
government made to protect human health? |
1.8 Where can I get more information? |
References |
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December 1990 |
Public Health Statement |
for |
Chlorobenzene |
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This Public Health Statement is the
summary chapter from the Toxicological
Profile for chlorobenzene. 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.
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This Statement was prepared to give you
information about chlorobenzene and to emphasize the human
health effects that may result from exposure to it. The Environmental
Protection Agency (EPA) has identified 1,177 sites on its
National Priorities List (NPL). Chlorobenzene has been found
at 97 of these sites. However, we do not know how many of
the 1,177 NPL sites have been evaluated for chlorobenzene.
As EPA evaluates more sites, the number of sites at which
chlorobenzene is found may change. The information is important
for you because chlorobenzene may cause harmful health effects
and because these sites are potential or actual sources of
human exposure to chlorobenzene.
When a chemical 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 as a chemical
emission. This emission, which is also called a release, does
not always lead to exposure. You can be exposed to a chemical
only when you come into contact with the chemical. You may
be exposed to it in the environment by breathing, eating,
or drinking substances containing the chemical or from skin
contact with it.
If you are exposed to a hazardous substance
such as chlorobenzene, several factors will determine whether
harmful 'health effects will occur and what the type and severity
of those health effects will be. These factors include the
dose (how much), the duration (how long), the route or pathway
by which you are exposed (breathing, eating, drinking, or
skin contact), the other chemicals to which you are exposed,
and your individual characteristics such as age, sex, nutritional
status, family traits, life style, and state of health.
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1.1
What is chlorobenzene? |
Chlorobenzene is a colorless liquid with
an almond-like odor. The compound does not occur widely in
nature, but is manufactured for use as a solvent (a substance
used to dissolve other substances) and is used in the production
of other chemicals. Chlorobenzene persists in soil (several
months), in air (3.5 days), and water (less than 1 day).
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1.2
How might I be exposed to chlorobenzene? |
There is potential for humans to be exposed
to chlorobenzene by breathing contaminated air, by drinking
water or eating food contaminated with chlorobenzene, or by
getting chlorobenzene contaminated soil on the skin. These
exposures are most likely to occur in the workplace or in
the vicinity of chemical waste sites.
Occupational exposure occurs primarily
through breathing the chemical. Personnel engaged in the production
and handling of chlorobenzene would be at greatest risk. Levels
of chlorobenzene in the air at several industrial sites during
normal operations were found to be below allowable federal
standards. Exposure in humans could occur in persons living
or working in the vicinity of hazardous waste sites if emissions
to water, air, and soil are not adequately controlled.
Chlorobenzene has been found at 97 out
of 1,177 NPL hazardous waste sites in the United States. Thus,
federal and state surveys suggest that chlorobenzene is not
a widespread environmental contaminant. The chemical has not
been detected in surface water, although a few ground water
systems have been found with chlorobenzene levels in the parts
per billion (ppb) range. Background levels of less than 1
ppb were detected in air samples from urban and suburban areas.
No information of the occurrence of chlorobenzene in food
has been found.
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1.3
How can chlorobenzene enter and leave my body? |
Chlorobenzene enters your body when you
breathe in air containing it, when you drink water or eat
food containing it, or when it comes in contact with your
skin. Human exposure to contaminated water could occur near
hazardous waste sites where chlorobenzene is present. Significant
exposure to chlorobenzene is not expected to occur by getting
chlorobenzene contaminated soil on your skin. When chlorobenzene
enters your body, most of it is expelled from your lungs in
the air we breathe out and in urine.
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1.4
How can chlorobenzene affect my health? |
Workers exposed to high levels of chlorobenzene
complained of headaches, numbness, sleepiness, nausea, and
vomiting. However, it is not known if chlorobenzene alone
was responsible for these health effects since the workers
may have also been exposed to other chemicals at the same
time. Mild to severe depression of functions of parts of the
nervous system is a common response to exposure to a wide
variety of industrial solvents (a substance that dissolves
other substances).
In animals, exposure to high concentrations
of chlorobenzene affects the brain, liver, and kidneys. Unconsciousness,
tremors and restlessness have been observed. The chemical
can cause severe injury to the liver and kidneys. Data indicate
that chlorobenzene does not affect reproduction or cause birth
defects. Studies in animals have shown that chlorobenzene
can produce liver nodules, providing some but not clear evidence
of cancer risk.
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1.5
What levels of exposure have resulted in harmful effects? |
It is not known what levels of exposure
to chlorobenzene result in harmful health effects in people.
In animals, exposure to 75 parts per million (ppm) chlorobenzene
in air or approximately 2,0005,000 ppm in food resulted
in liver and kidney damage.
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1.6
Is there a medical test to determine whether I have been exposed
to chlorobenzene? |
Exposure to chlorobenzene can be determined
by measuring the chemical or its metabolite in urine, exhaled
air, blood, and body fat. Tests are not routinely available
at the doctor's office. Specific tests are available that
can determine if exposure is currently occurring or has occurred
very recently, but not whether exposure occurred in the past.
Further, levels in the various media stated above do not predict
adverse health effects.
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1.7
What recommendations has the federal government made 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 recommendations have been
updated as of July 1999.
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1.8 Where can I get more information? |
If you have any more questions or concerns, please contact
your community or state health or environmental quality department or:
Agency for Toxic Substances and Disease Registry
Division of Toxicology
1600 Clifton Road NE, Mailstop F-32
Atlanta, GA 30333
Information line and technical assistance:
Phone: 888-422-8737
FAX: (770)-488-4178
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.
To order toxicological profiles, contact:
National Technical Information Service
5285 Port Royal Road
Springfield, VA 22161
Phone: 800-553-6847 or 703-605-6000
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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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