Ethylbenzene is a colorless liquid that smells like gasoline. It evaporates at room temperature and burns easily. Ethylbenzene occurs naturally in coal tar and petroleum. It is also found in many man-made products, including paints, inks, and insecticides. Gasoline contains about 2 percent (by weight) ethylbenzene. It is most commonly found as a vapor in the air. This is because ethylbenzene moves easily into the air from water and soil. Once in the air, other chemicals help break down ethylbenzene into chemicals found in smog. This breakdown happens in about 3 days with the aid of sunlight. In surface water such as rivers and harbors, ethylbenzene breaks down by reacting with other compounds naturally present in the water. In soil, the major way ethylbenzene is broken down is by soil bacteria. It can also move very quickly into groundwater, since it does not readily bind to soil. Near hazardous waste sites, the levels of ethylbenzene in the air, water, and soil could be much higher than in other areas.
There are a variety of ways you may be exposed to this chemical. If you
live in a highly populated area or near many factories or heavily traveled
highways, you may be exposed to ethylbenzene in the air. Releases of
ethylbenzene into these areas occur from burning oil, gas, and coal and
from discharges of ethylbenzene from some types of factories. The median
level of ethylbenzene in city air is about 0.62 parts of ethylbenzene per
billion parts (ppb) of air. The median level in suburban air is about 0.62
ppb. In contrast, the median level of ethylbenzene measured in air in
country locations is about 0.01 ppb. Indoor air has a higher median
concentration of ethylbenzene (about 1 ppb) than outdoor air. This is
because ethylbenzene builds up after you use household products such as
cleaning products or paints.
Ethylbenzene was found in only 1 out of 10 of the United States rivers and
streams tested in 1982 and 1983. The average level measured was 5.0 ppb.
Ethylbenzene gets into water from factory releases, boat fuel, and poor
disposal of waste. Background levels in soils have not been reported.
Ethylbenzene may get into the soil by gasoline or other fuel spills and
poor disposal of industrial and household wastes.
Some people are exposed to ethylbenzene in the workplace. Gas and oil
workers may come into contact with ethylbenzene either through the skin or
by breathing ethylbenzene vapors. Varnish workers, spray painters and
persons involved in gluing operations may also be exposed to high levels of
ethylbenzene. Exposure may also occur in factories that use ethylbenzene to
produce other chemicals. Families of these workers may be exposed to
ethylbenzene through contact with contaminated clothing.
You may be exposed to ethylbenzene if you live near hazardous waste sites
containing ethylbenzene or areas where ethylbenzene spills have occurred.
Higher than background levels of ethylbenzene were detected in groundwater
near a landfill and near an area where a fuel spill had occurred. No
specific information on human exposure to ethylbenzene near hazardous waste
sites is available.
You may also be exposed to ethylbenzene from the use of many consumer
products. Gasoline is a common source of ethylbenzene exposure. Other
sources of ethylbenzene exposure come from the use of this chemical as a
solvent in pesticides, carpet glues, varnishes and paints, and from the use
of tobacco products. Ethylbenzene does not generally build up in food.
However, some vegetables may contain very small amounts of it.
When you breathe air containing ethylbenzene vapor, it enters your body
rapidly and almost completely through your lungs. Ethylbenzene in food or
water can also rapidly and almost completely enter your body through the
digestive tract. It may enter through your skin when you come into contact
with liquids containing ethylbenzene. Ethylbenzene vapors do not enter
through your skin to any large degree. People living in urban areas or in
areas near hazardous waste sites may be exposed by breathing air or by
drinking water contaminated with ethylbenzene.
Once in your body, ethylbenzene is broken down into other chemicals. Most
of it leaves in the urine within 2 days. Small amounts can also leave
through the lungs and in feces. Liquid ethylbenzene also enters through
your skin and is broken down. Ethylbenzene in high levels is broken down
slower in your body than low levels of ethylbenzene. Similarly,
ethylbenzene mixed with other solvents is also broken down more slowly than
ethylbenzene alone. This slower breakdown may increase the time it takes
for ethylbenzene to leave your body.
At certain levels, exposure to ethylbenzene can harm your health. People
exposed to low levels of ethylbenzene in the air for short periods of time
have complained of eye and throat irritation. Persons exposed to higher
levels have shown signs of more severe effects such as decreased movement
and dizziness. No studies have reported death in humans following exposure
to ethylbenzene. However, evidence from animals suggests that it can cause
death at very high concentrations. Whether or not long-term exposure to
ethylbenzene affects human health is not known because little information
is available. Short-term exposure of laboratory animals to high
concentrations of ethylbenzene in air may cause liver and kidney damage,
nervous system changes, and blood changes. The link between these health
effects and exposure to ethylbenzene is not clear because of conflicting
results and weaknesses in many of the studies.
Also, there is no clear evidence that the ability to get pregnant is
affected by breathing air, drinking water containing ethylbenzene, or
coming into direct contact with ethylbenzene through the skin. Birth
defects have occurred in newborn animals whose mothers were exposed by
breathing air contaminated with ethylbenzene. The seriousness of these
effects seems to increase with higher exposure levels. One long-term study
in animals suggests that ethylbenzene may cause tumors. However, this study
had many weaknesses and no conclusions could be drawn about possible cancer
effects in humans. EPA has determined that ethylbenzene is not classifiable
as to human carcinogenicity.
Low levels of ethylbenzene in the air may cause harmful health effects.
More serious effects to your health may occur at higher levels. You can
smell ethylbenzene in the air at concentrations as low as 2 parts of
ethylbenzene per million parts of air by volume (ppm).
There are no reliable data on the effects in humans after eating, drinking,
or breathing ethylbenzene or following direct exposure to the skin. For
this reason, levels of exposure that may affect your health are estimated
from animal studies. Only two reports described the results of eye or skin
exposure to ethylbenzene. In these studies, liquid ethylbenzene caused eye
damage and skin irritation in rabbits. More animal studies are available
that describe the effects of breathing air or drinking water containing
Information excerpted from
Toxicological Profile for Ethylbenzene December 1990 Update
Agency for Toxic Substances and Disease Registry
United States Public Health Service