United States
Environmental Protection
Agency
Pollution Prevention
and Toxics
(7407)
January 1995
EPA 749-F-95-007
wEPA OPPT Chemical Fact Sheets
Chlorobenzene (CAS No. 108-90-7)
Chemicals can be released to the environment as a result of their
manufacture, processing, and use. EPA has developed information
summaries on selected chemicals to describe how you might be
exposed to these chemicals, how exposure to them might affect you
and the environment, what happens to them in the environment, who
regulates them, and whom to contact for additional information. EPA is
committed to reducing environmental releases of chemicals through
source reduction and other practices that reduce creation of pollutants.
WHAT IS CHLOROBENZENE, HOW IS IT USED, AND HOW MIGHT I BE EXPOSED?
Chlorobenzene (also called monochlorobenzene or MCB) is a flammable liquid. It does not occur naturally.
It is produced in large amounts (231 million pounds in 1992) in the United States by three companies. U.S. demand is
likely to remain constant over the next several years. Because of environmental concerns for chlorinated organic
chemicals in general, future U.S. demand for MCB is likely to decline. The largest users of MCB are companies that
make nitrochlorobenzene. Companies also use MCB to make adhesives, paints, paint removers, polishes, dyes, and
drugs. In the past companies have used MCB to make phenol and related chemicals, pesticides (like DDT), and
aniline.
Exposure to chlorobenzene can occur in the workplace or in the environment following releases to air, water,
land, or groundwater. Exposure can also occur when people use paints and paint removers that contain MCB.
Chlorobenzene enters the body when people breathe air contaminated with MCB or consume food or water
contaminated with MCB. It can also be absorbed through skin contact. MCB does not remain in the body due to its
breakdown and removal.
WHAT HAPPENS TO CHLOROBENZENE IN THE ENVIRONMENT?
Chlorobenzene can evaporate when exposed to air. It dissolves slightly when mixed with water. Most
releases of chlorobenzene to the U.S. environment are to air. MCB also can evaporate from water and soil exposed to
air. Once in air, MCB breaks down to other chemicals. Because it is a liquid that does not bind well to soil, MCB that
makes its way into the ground can move through the ground and enter groundwater. Plants and animals are not likely
to store chlorobenzene.
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CHLOROBENZENE January 1995
CAS No. 108-90-7
HOW DOES CHLOROBENZENE AFFECT HUMAN HEALTH AND THE ENVIRONMENT?
Effects of chlorobenzene on human health and the environment depend on how much chlorobenzene is present
and the length and frequency of exposure. Effects also depend on the health of a person or the condition of the
environment when exposure occurs.
Contact with chlorobenzene liquid or vapor can irritate the skin, the eyes, the nose, and the throat. Exposure
to large amounts of chlorobenzene can also cause adverse nervous system effects, including unconsciousness. These
effects disappear when exposure stops. These acute effects are not likely to occur at levels of chlorobenzene that are
normally found in the U.S. environment.
Workers breathing large amounts of MCB can experience headaches, muscle spasms, and adverse effects on
the bone marrow. Other human health effects associated with repeat exposure to small amounts of chlorobenzene over
long periods of time are not known. Laboratory studies show that repeat exposure to chlorobenzene in air affects the
nervous system of animals. Repeat exposure to large amounts of MCB can also adversely affect the liver, kidneys,
and the blood of animals. The chlorinated benzene industry has submitted to EPA results of EPA requested
reproductive effects testing on MCB. Results show that exposure to moderate amounts of chlorobenzene in air causes
testicular damage in animals.
Chlorobenzene is moderately toxic to aquatic organisms. Chlorobenzene is not likely to cause environmental
harm at levels normally found in the U.S. environment.
WHAT EPA OFFICES OR OTHER FEDERAL AGENCIES OR OTHER GROUPS CAN I CONTACT FOR
ADDITIONAL INFORMATION ON CHLOROBENZENE?
EPA OFFICE STATUTE PHONE NUMBER
Pollution Prevention Pollution Prevention Act (PPA) (202) 260-1023
& Toxics Emergency Planning and
Community Right-to-Know
Act (EPCRA) (§ 313/TRI) (800) 535-0202
Toxic Substances Control Act
(TSCA) (§4, §8A, §8D) (202)554-1404
Air Clean Air Act (919)541-0888
Solid Waste & Resource Conservation and
Emergency Response Recovery Act (RCRA) (800) 535-0202
Comprehensive Environmental
Response, Compensation, and
Liability Act (CERCLA) (800) 535-0202
Water Safe Drinking Water Act (800) 426-4791
Clean Water Act (202) 260-7588
OTHER FEDERAL AGENCY/DEPARTMENT OR GROUP PHONE NUMBER
Agency of Toxic Substances & Disease Registry (404) 639-6000
American Conference of Governmental Industrial Hygenists (513) 742-2020
Consumer Product Safety Commission (301) 504-0994
Food & Drug Administration (301) 443-3170
National Institute for Occupational Safety & Health (800) 356-4674
Occupational Safety & Health Administration
(Check local phone book for phone number under Department of Labor)
The Support Document for this and other OPPT Chemical Fact Sheets can be found on the Internet at:
http://www.epa.gov/chemfact
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