United States
Environmental Protection
Agency
Office of Pesticides and
Toxic Substances TS-793
Washington D C 20460
v>EPA
Benzene—
what is it?
Why is
benzene a
problem?
Toxics Information
Series
Benzene
First discovered in 1825, benzene has been
commercially produced and used since the I860's. It has
been produced in large quantities in the U.S. since the
1940's and is used as the basis for many other important
chemical compounds. The toxicity of benzene is well-
documented. As early as the 1920's, benzene was thought
to be associated with leukemia. More recent information
has provided stronger evidence of benzene's relationship
to human cancer and serious questions are being raised
about its potential for producing genetic mutations.
These concerns, together with other suspected adverse
health effects, have prompted government action to limit
public exposure to the chemical. This Information
Bulletin addresses the hazards of benzene and describes
the efforts of the U.S. Environmental Protection Agency
(EPA) and others to safeguard public health from the
hazards of benzene.
Benzene is a unique organic ring formation made up
of hydrogen and carbon molecules. The benzene ring is
retained throughout many chemical reactions, rather than
being rearranged, as are most compounds. The stability
of benzene makes it an important basic ingredient for
other chemical compounds.
Benzene is used as a constituent in gasoline, in
the manufacture of dyes, artificial leathers, linoleum,
varnishes, lacquers and medicinal chemicals, and as a
solvent in waxes, resins and oils. Some 12.72 billion
pounds of benzene were produced in the U.S. in 1979.
More than half was used in gasoline production.
Although benzene is used throughout the country, it is
produced in large volumes in only a few States.
Production in Texas alone is more than 50% of the total
volume, followed by New York and New Jersey with a
combined total of 20%. Other, major producing facilities
are located in the north central and midwestern States.
Human exposure to benzene is widespread due to the
prevalent uses of the chemical. Very easily evaporated,
benzene is an air contaminant emitted through factory
vents and stacks during handling and storage, as well as
from gasoline vapors and auto emissions. It can be
absorbed through the skin or inhaled The public can
also be exposed to small concentrations of benzene in
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What
is the
government
doing about
this hazard?
drinking water since benzene can enter water systems
through run-off from gas and oil, industrial spills and
dump sites. The presence of benzene in foods—ranging
from fruits and vegetables to dairy products, meat, fish
and poultry—is well documented.
Benzene is suspected of causing nerve damage, blood
disorders and cancer in humans, and genetic damage in
laboratory animals. When benzene is absorbed by the
body, approximately 50% is retained and either stored in
fatty tissue or bone marrow or metabolized by the body
into a number of different compounds. Toxic effects
associated with benzene exposure are thought to be
caused by one or more of these metabolic products.
Nerve and blood disorders; Acute (exposure to high
concentrationsovershorttime intervals) and chronic
(exposure to low concentrations over a prolonged time
period) benzene poisoning are shown through nerve and
blood disorders. The primary acute effects of benzene
are on the central nervous system, which can include the
following symptoms: confusion, dizziness, tightening of
leg "muscles, pressure over the forehead, excitation and
finally coma. Chronic exposure to benzene may induce
fatigue, dizziness, nausea and loss of appetite, weight
loss and weakness in the early stages, as well as
chances in the hematopoietic (blood-forming) system.
Symptoms of chronic exposure include: pallor, nose-
bleeds, .bleeding gums, excessive menstrual bleeding,
small hemorrhages in the skin, headache, ,nausea,
internal bleeding, and unconsciousness.
Damage resulting from benzene exposure is
cumulative and permanent. In addition, people exposed
to benzene are at a greater risk if they also suffer
from anemia, respiratory disease, alcholism, heart
disease, kidney disease, or obesity.
Cancer: The World Health Organization's Interna-
tional Agency for Research on Cancer has identified
benzene^ as a human carcinogen. Epidemiological studies
have ""shown a relationship, well accepted by the medical
community, between benzene exposure and leukemia.
Cancer was first, associated with benzene in the 1920's,
but a direct relationship was not made until the late
1970's.
Genetic damage; Benzene also produces chromosomal
changes or mutations in experimental animals.
Occupational studies indicate that benzene exposure also
causes damage to chromosomes in exposed workers.
Several Federal agencies, such as EPA, the
Occupational Safety and Health Administration (OSHA),
and the Consumer Product Safety Commission this (CPSC),
are working to control public exposure to benzene. OSHA
set a workplace standard of ten parts benzene to one
million parts air (10 ppm) several years ago. Although
a recent OSHA regulation designed to reduce levels of
benzene in the workplace was overturned by the Supreme
Courts, OSHA continues to investigate methods of
reducing benzene exposure.
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CPSC presently requires warning labels on consumer
products containing more than five percent benzene.
CPSC has determined that benzene is no longer being
intentionally added to consumer products and that of the
10% of those products which contain more than 0.1%
benzene (as a contaminant), none contain more than
0.25%.
EPA listed benzene as a hazardous air contaminant
in 1977, and has begun controlling benzene air emissions
from major industries and other stationary sources. The
agency has proposed a limit on benzene emissions from
maleic anhydride plants, the largest stationary source
of benzene air contamination, which should reduce such
emissions by 97%. EPA has also proposed emission limits
for ethylbenzene/styrene plants, benzene storage and
handling, and chemical plant fugitive emissions. Plans
are also underway to control coke by-product plants.
Benzene is also identified as one of the chemicals on
EPA's list of priority water pollutants. Final water
quality criteria for benzene were published by EPA in
November 1980. These criteria include the latest
scientific information on health effects and sources of
benzene pollution, and can be used as the basis f c r
regulation of water pollution sources by EPA and the
individual states. EPA has also proposed regulation of
several benzene compounds under the authority of the
Clean Water Act in order to reduce the discharge of
benzene into the nation's waterways. EPA has obtained
voluntary cancellations under FIFRA for all pesticide
products containing benzene as an active ingredient.
However, benzene could still be contained in certain
pesticide products as a contaminant of petroleum
distillates or as an inert ingredient. Waste products
from benzene production are cited as hazardous, and
therefore are subject to regulation by EPA under the
Resource Conservation and Recovery Act (RCRA).
EPA and the Department of Transportation have each
issued regulations governing the transportation of
benzene and benzene wastes, including labeling and
container requirements and a manifest system for
tracking hazardous wastes from point of generation to
final disposal.
In Summary: Benzene remains a major cause for
concern because of its wide usage and its known
carcinogenic and possible mutagenic effects in humans.
Federal agencies are continuing to research the health
effects of benzene and to formulate regulations which
will reduce the public's exposure to the substance.
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