1.1 What is HCCPD? |
1.2 What happens to HCCPD when it enters
the environment? |
1.3 How might I be exposed to HCCPD? |
1.4 How can HCCPD enter and leave my body? |
1.5 How can HCCPD affect my health? |
1.6 How can HCCPD affect children? |
1.7 How can families reduce the risk of
exposure to HCCPD? |
1.8 Is there a medical test to determine
whether I have been exposed to HCCPD? |
1.9 What recommendations has the federal
government made to protect human health? |
1.10 Where can I get more information? |
References |
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July 1999 |
Public Health Statement |
for |
Hexachlorocyclopentadiene (HCCPD) |
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This Public Health Statement is the
summary chapter from the Toxicological
Profile for hexachlorocyclopentadiene (HCCPD). 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 public health statement tells you
about hexachlorocyclopentadiene (HCCPD) and the effects of
exposure.
The Environmental Protection Agency (EPA)
identifies the most serious hazardous waste sites in the nation.
These sites make up the National Priorities List (NPL) and
are the sites targeted for long-term federal cleanup activities.
HCCPD has been found in at least 31 of the 1,467 current or
former NPL sites. However, the total number of NPL sites
evaluated for this substance is not known. As more sites
are evaluated, the sites at which HCCPD is found may increase.
This information is important because exposure to this substance
may harm you and because these sites may be sources of exposure.
When a substance 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. This
release does not always lead to exposure. You are exposed
to a substance only when you come in contact with it.
You may be exposed by breathing, eating, or drinking the substance
or by skin contact.
If you are exposed to HCCPD, many factors
determine whether you'll be harmed. These factors include
the dose (how much), the duration (how long), and how you
come in contact with it. You must also consider the
other chemicals you're exposed to and your age, sex, diet,
family traits, lifestyle, and state of health.
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1.1
What is HCCPD? |
HCCPD is a light, lemon-yellow liquid
that has a sharp, musty odor. It easily turns from a
liquid to a vapor when exposed to air. The vapor looks
like a blue haze. This chemical is also called percyclopentadiene,
hexachloropentadiene, and hex. Some of its former trade names,
still listed in chemical reference documents, are C-56, Graphlox,
and HRS 1655.
HCCPD is a manufactured chemical and
does not occur naturally in the environment. It is made
by adding chlorine to cyclopentadiene, or by removing chlorine
from octachlorocyclopentane. HCCPD is used to make a
group of related pesticides (aldrin, chlordane, dieldrin,
endosulfan, endrin, heptachlor, isodrin, mirex, and pentac).
Only two of these pesticides, endosulfan and pentac, are currently
registered for use in the United States. Thus, your
exposure to these compounds is expected to be limited.
Endosulfan and pentac are the only two of these pesticides
that you can buy in a store. HCCPD is also used to make
flame retardants, resins that won't burn, shock-proof plastics,
esters, ketones, fluorocarbons, and dyes.
Most of the HCCPD in the environment
results from releases during its production and disposal.
Releases can also occur as a result of the manufacture, use,
and disposal of pesticides made from HCCPD. Most people
can smell HCCPD in the air at 30 parts HCCPD per billion (ppb)
parts of air. Most people can smell it in water when
it is present at 1.4 ppb. The amount of HCCPD that you
can taste in water has not been measured and the taste has
not been described.
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1.2
What happens to HCCPD when it enters the environment? |
HCCPD can be released to the air as a
vapor during its production and use. However, it does
not remain in the air very long since it is usually broken
down to other substances by sunlight and by reaction with
other chemicals in the air. Half of the HCCPD released
to the air is removed in less than one day.
When HCCPD is mixed with water at room
temperature, only 2.1 milligrams will dissolve in a liter
of water (2 parts per million or 2 ppm). In a stream
or small river, the HCCPD near the surface will evaporate
to the air. Sunlight on the water will cause HCCPD to
change quickly into other chemicals. About half of the
HCCPD in the water will be changed to other chemicals by the
light in only four minutes.
The HCCPD that gets into soil binds to
decaying plant and animal matter. If the soil is sandy,
the HCCPD can move through the soil and reach the water that
is under the ground. When soil that contains HCCPD
also contains solvents like gasoline, paint thinners, and
acetone, these liquids will help carry the HCCPD through the
soil to lakes, rivers, or wells. Bacteria can change
HCCPD in the soil to other chemicals, but scientists do not
know the nature of these compounds. About half of the
HCCPD in the soil will be changed to other chemicals by bacteria
in 1–2 weeks.
HCCPD has been known to build up in fish,
but only in very small amounts. We do not know if HCCPD
accumulates in plants, milk, or animals used for food.
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1.3
How might I be exposed to HCCPD? |
If you live near a hazardous waste site
where HCCPD or HCCPD-derived pesticides were disposed, you
might be exposed to HCCPD in the air. In one survey,
levels ranging from 0.032 to 0.053 ppb were measured
in air near a hazardous waste site. HCCPD has not been
reported in outdoor air in city, suburban, and rural areas.
In most areas, the concentration of HCCPD in the air should
be low because this chemical is not widely used.
HCCPD is not commonly found in surface
water. In one survey, it was found in less than 0.1%
of 854 water samples from various sources. The median
concentration of HCCPD was less than 10 ppb in water.
HCCPD in not often found in drinking water, so exposure by
this route is unlikely. However, it may be formed during
chlorination of water containing humic acid.
HCCPD may be present in soils that have
recently been treated with the pesticides, endosulfan or pentac,
because it is sometimes found as an impurity in these pesticides.
The soils near a landfill where these pesticides (including
those no longer used, such as aldrin, chlordane, dieldrin,
endrin, heptachlor, and isodrin) or waste HCCPD were disposed
might also contain HCCPD, but, since it binds to organic matter
in soils, it is less likely to be free to affect you.
It is highly unlikely that you will be
exposed to HCCPD in the foods you eat, although you could
be exposed to very small amounts if you catch and eat fish
that lived in HCCPD-contaminated water.
The highest exposures to HCCPD are likely
to occur in people who are involved in the production or use
of HCCPD, who handle pesticides made from it, or who treat
wastes that contain it. These people can be exposed
by breathing air contaminated with HCCPD, or by skin and eye
contact with the vapors or liquid.
Air concentrations ranging from 270 to
970 ppb were reported at a waste water treatment plant after
large amounts of the compound were dumped into a city sewage
system. Traces of HCCPD were present in waste water
at another treatment plant near an industrial facility that
used it as a reactant for making pesticides.
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1.4
How can HCCPD enter and leave my body? |
There is no information available to
tell us what happens to HCCPD once it enters the human body.
Based on studies in animals, if you are exposed to HCCPD through
food or drinking water, most of the HCCPD you eat or drink
will stay bound to the food or water and only a small amount
will enter your bloodstream. Thereafter, most of the
HCCPD (64–80%) will leave your body in your feces and the
rest will leave in your urine.
Animal studies have shown that up to
95% of the HCCPD that is inhaled stays in your windpipe and
lungs, and a small amount reaches your liver and kidneys.
Inhaled HCCPD, therefore, causes more health effects in people
and animals than HCCPD that is ingested (see Section
1.5).
If HCCPD touches your skin, it can enter
your body. Based on studies in animals, when either
pure HCCPD or a solution with 10% HCCPD in mineral oil comes
in contact with your skin, a sore can form. The open
sore will allow more HCCPD to enter your body.
Most of the HCCPD that enters your body
is changed to other chemicals, but those chemicals have not
been identified. A small amount of HCCPD remains unchanged.
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1.5
How can HCCPD affect my health? |
To protect the public from the harmful
effects of toxic chemicals and to find ways to treat people
who have been harmed, scientists use many tests.
One way to see if a chemical will hurt
people is to learn how the chemical is absorbed, used, and
released by the body; for some chemicals, animal testing may
be necessary. Animal testing may also be used to identify
health effects such as cancer or birth defects. Without
laboratory animals, scientists would lose a basic method to
get information needed to make wise decisions to protect public
health. Scientists have the responsibility to treat
research animals with care and compassion. Laws today
protect the welfare of research animals, and scientists must
comply with strict animal care guidelines.
Information on the health effects of
HCCPD on people is limited to one incident involving short-term
exposure to HCCPD vapors (0.04–19.2 ppm). Exposure occurred
at a waste water treatment plant as a result of an industrial
release of HCCPD into the sewage system. This incident
showed that the breathing passageways (nose, throat, lungs)
in people are very sensitive to HCCPD. You may get a
sore throat or have shortness of breath and chest discomfort
if you breathe HCCPD at high levels. Your eyes may burn
and turn red, and your skin may be irritated. Some people
get headaches when they breathe high levels of HCCPD.
Your kidneys and liver may show signs
that you have been exposed to HCCPD. Some people who
were exposed to HCCPD had increased amounts of protein in
their urine and increased levels of other compounds in their
blood. These are signs that kidney and liver effects
may have occurred after exposure to HCCPD. Other people
who were exposed did not show these effects.
Bleeding, swelling, and fluid buildup
occurred in the lungs of rats, mice, guinea pigs, and rabbits
that inhaled small amounts of HCCPD vapors for two weeks under
controlled conditions. Severe breathing difficulty was
seen in animals exposed to large amounts of HCCPD for a short
period of time, and all the animals died during or soon after
exposure. In rats, some cells of the lung, windpipe, and nose
contained yellow-colored or clear granules after exposure
to a very low level (0.01 ppm) of HCCPD in air for a long
time. In monkeys, higher levels (0.2 ppm) caused
similar changes in those cells.
When rats and rabbits swallowed HCCPD
dissolved in corn oil or peanut oil, cells in the lungs, liver,
kidney, brain, and heart were harmed and a sore formed in
the stomach lining. When the doses were high (261–1,950
milligrams per kilogram of body weight [mg/kg]), most of the
animals died after only one dose. There was damage to
stomach lining and kidney cells in mice given a low concentration
of HCCPD in corn oil by mouth 5 days a week for several months.
Because these mice were also exposed to another chemical,
hexachlorobutadiene, it is not clear if the cell damage in
the kidneys was caused by HCCPD alone.
No information is available on whether
HCCPD affects the reproductive organs of people.
No information is available on whether
HCCPD causes cancer in people. The Department of Health
and Human Services (DHHS) has determined that HCCPD does not
cause cancer in rats and mice under the conditions of the
study conducted by the National Toxicology Program.
The International Agency for Research on Cancer (IARC) has
not evaluated HCCPD as a possible cancer-causing chemical.
The EPA has determined that HCCPD is not classifiable as to
its ability to cause cancer in people.
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1.6
How can HCCPD affect children? |
This section discusses potential health
effects from exposures during the period from conception to
maturity at 18 years of age in humans.
Children are unlikely to be exposed to
HCCPD. There is no information on the effects of exposure
to HCCPD in children or in adults who were exposed as children.
We do not know whether HCCPD causes birth defects in humans.
Studies in animals indicate that exposure to HCCPD does not
cause problems during development. HCCPD did not cause
birth defects or impair the ability of mice and rabbits to
produce offspring. We do not know whether HCCPD can cross
the placenta or accumulate in breast milk.
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1.7
How can families reduce the risk of exposure to HCCPD? |
If your doctor finds that you have been
exposed to significant amounts of HCCPD, he or she can advise
you about the potential risk of exposure to the rest of your
family. When necessary your doctor may need to ask your
state public health department to investigate.
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1.8
Is there a medical test to determine whether I have been exposed
to HCCPD? |
If you have been recently exposed to
HCCPD, your blood and urine can be tested for its presence.
Such tests are not routinely done in a doctor's office because
special equipment is needed. Doctors often can collect
blood or urine samples and send them to special laboratories
to determine if you have been exposed to HCCPD; but these
laboratories can't determine how much HCCPD you were exposed
to, or whether your health will be affected. Exposure
to HCCPD that occurred weeks or months before your test is
not likely to be detected in either your blood or urine.
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1.9 What recommendations has the federal government made to protect human health? |
The federal government develops regulations
and recommendations to protect public health. Regulations
can be enforced by law. Federal agencies that
develop regulations for toxic substances include the Environmental
Protection Agency (EPA), the Occupational Safety and Health
Administration (OSHA), and the Food and Drug Administration
(FDA). Recommendations provide valuable guidelines to
protect public health but cannot be enforced by law.
Federal organizations that develop recommendations for toxic
substances include the Agency for Toxic Substances and Disease
Registry (ATSDR) and the National Institute for Occupational
Safety and Health (NIOSH).
Regulations and recommendations can be
expressed in not-to-exceed levels in air, water, soil, or
food that are usually based on levels that affect animals,
then they are adjusted to help protect people. Sometimes
these not-to-exceed levels differ among federal organizations
because of different exposure times (an 8-hour workday or
a 24-hour day), the use of different animal studies, or other
factors.
Recommendations and regulations are also
periodically updated as more information becomes available.
For the most current information, check with the federal agency
or organization that provides it. Some regulations and
recommendations for HCCPD include the following:
To protect workers who may be exposed
to HCCPD on the job, the Occupational Safety and Health Administration
(OSHA) limits HCCPD exposure to 0.01 ppm in air for an 8-hour
workday over a 40-hour workweek. The National Institute
for Occupational Safety and Health (NIOSH) suggests the same
limit for workplace air.
EPA has recommended guidelines on how
much HCCPD can be present in drinking water. The maximum
contaminant levels (MCL) and maximum concentration level goal
(MCLG) for drinking water are 50 ppb. EPA recommends
that exposures in children should not exceed 2 ppm in water
for 10-day periods or no more than 0.7 ppb for up to 7 years.
If adults are exposed for more than 7 years, the EPA recommends
that exposure levels should not exceed 50 ppb.
HCCPD has been named a hazardous substance
by EPA. If quantities equal to or greater than one pound
are released to the environment, the National Response Center
for the federal government must be told immediately.
HCCPD has not been identified as a carcinogen.
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1.10 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). 1999. Toxicological
profile for hexachloropentadiene (HCCPD). Atlanta, GA:
U.S. Department of Health and Human Services, Public Health
Service.
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