1.1 What is nitrobenzene? |
1.2 How might I be exposed to nitrobenzene? |
1.3 How can nitrobenzene enter and leave
my body? |
1.4 How can nitrobenzene affect my health? |
1.5 What levels of exposure have resulted
in harmful health effects? |
1.6 Is there a medical test to determine
whether I have been exposed to nitrobenzene? |
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 |
Nitrobenzene |
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This Public Health Statement is the
summary chapter from the Toxicological
Profile for nitrobenzene. 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 nitrobenzene 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). Nitrobenzene has been found
at 7 of these sites. However, we do not know how many of the
1,177 NPL sites have been evaluated for nitrobenzene. As EPA
evaluates more sites, the number of sites at which nitrobenzene
is found may change.
The information is important for you
because nitrobenzene may cause harmful health effects and
because these sites are potential or actual sources of human
exposure to nitrobenzene. 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 nitrobenzene,
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 nitrobenzene? |
Nitrobenzene is an oily yellow liquid
with an almond-like odor. It may be pale yellow-brown in appearance.
It dissolves only slightly in water, but very easily in some
other chemicals.
Nitrobenzene is produced in large quantities
for industrial use. Approximately 98% of the nitrobenzene
produced in the United States is used to manufacture a chemical
known as aniline. Nitrobenzene is also used to produce lubricating
oils such as those used in motors and machinery. A very small
amount of nitrobenzene is used in the manufacture of dyes,
drugs, pesticides, and synthetic rubber.
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1.2
How might I be exposed to nitrobenzene? |
Small amounts of nitrobenzene are released
to the air and to bodies of water by the industries that use
this chemical. However, it is broken down to other chemicals
within a few days after it is released. Air and water in most
areas contain no nitrobenzene or such low amounts that they
cannot be measured.
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1.3
How can nitrobenzene enter and leave my body? |
Because nitrobenzene is not usually found
at hazardous waste sites, it is unlikely that you will be
exposed to nitrobenzene if you live near one of these sites.
However, you may be exposed if you live near one of the seven
waste sites where it has been found or near a manufacturing
or processing plant, such as those involved in petroleum refining
and chemical manufacturing. Persons in these areas may be
exposed to nitrobenzene in the air they breathe. However,
even in these cases, the levels of nitrobenzene have been
found to be extremely low, usually less than 1 ppb (one part
nitrobenzene per billion parts of air). Levels of nitrobenzene
in the air of residential areas are even lower. Nitrobenzene
is almost never found in drinking water. There is no information
available on the levels of nitrobenzene in food.
The most common way that humans are exposed
to this compound is by occupational exposure. If you work
in a plant or factory that produces nitrobenzene or uses nitrobenzene
to make other products such as dyes, drugs, pesticides or
synthetic rubber, you may be exposed to nitrobenzene in the
air that you breathe or through your skin.
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1.4
How can nitrobenzene affect my health? |
Nitrobenzene can cause a wide variety
of harmful health effects to exposed persons. Direct contact
of small amounts of nitrobenzene with the skin or eyes may
cause mild irritation. Repeated exposures to a high concentration
of nitrobenzene can result in a blood condition called methemoglobinemia.
This condition affects the ability of the blood to carry oxygen.
Following such an exposure, the skin
may turn a bluish color. This may be accompanied by nausea,
vomiting and shortness of breath. Effects such as headache,
irritability, dizziness, weakness, and drowsiness may also
occur. If the exposure level is extremely high, nitrobenzene
can cause coma and possibly death unless prompt medical treatment
is received. Consuming alcoholic beverages during nitrobenzene
exposure may increase the harmful effects of nitrobenzene.
In studies with laboratory animals, a single dose of nitrobenzene
fed to male rats resulted in damage to the testicles and decreased
levels of sperm. This suggests that decreased fertility may
be a concern in humans. There is very little information available
about the effects of long-term exposure of humans or animals
to nitrobenzene, and it is not known whether exposure to nitrobenzene
can cause cancer.
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1.5
What levels of exposure have resulted in harmful health effects? |
Nitrobenzene can be smelled in water
when it is present at 0.11 mg/L (milligrams of nitrobenzene
per liter of water) or in air at 0.018 ppm (0.018 parts of
nitrobenzene per million parts of air). It has an odor characteristic
of bitter almonds or shoe polish.
It is not known what nitrobenzene levels
result in harmful health effects in people. Damage to the
kidneys and increased methemoglobinemia in rats is seen at
5 ppm. Damage to the spleen, liver, and testes of rats has
been noted at levels of 50 ppm nitrobenzene in air.
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1.6
Is there a medical test to determine whether I have been exposed
to nitrobenzene? |
Nitrobenzene reacts with red blood cells
in the body to produce methemoglobin. If you have recently
been exposed to nitrobenzene, the levels of methemoglobin
in your blood will be elevated. This level can be measured.
However, many toxic chemicals produce methemoglobin, and this
method does not give specific information about nitrobenzene
exposure.
In cases of long-term exposure to nitrobenzene,
the presence of its breakdown products, p-nitrophenol and
p-aminophenol, in the urine is an indication of nitrobenzene
exposure. These tests require special equipment and cannot
be routinely done in a doctor's office. The results of these
tests cannnot be used ot determine the level of nitrobenzene
esposure or if harmful health effects can be expected to occur.
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1.7
What recommendations has the federal government made to protect
human health? |
The National Institute for Occupational
Safety and Health (NIOSH) recommends an occupational exposure
limit of 23 mg/m³ for nitrobenzene for a 10-hour workday in
a 40-hour workweek.
The EPA recommends that levels in lakes
and streams should be limited to 17 parts of nitrobenzene
per million parts of water (17 ppm) to prevent possible health
effects from drinking water or eating fish contaminated with
nitrobenzene.
The EPA requires that discharges, spills,
or accidental releases of 1,000 pounds or more of nitrobenzene
must be reported to the EPA.
The Occupational Safety and Health Administration
(OSHA) has set a permissible exposure limit of 5 milligrams
nitrobenzene per cubic meter of air (5 mg/m³)
for an 8-hour workday in a 40-hour workweek.
The American Conference of Governmental
and Industrial Hygienists (ACGIH) and the National Institute
for Occupational Safety and Health (NIOSH) also recommend
an occupational exposure limit of 5 mg/m³
for nitrobenzene.
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 nitrobenzene. Atlanta, GA: U.S. Department
of Health and Human Services, Public Health Service.
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