September 2003 |
ToxFAQs™ |
for |
Malathion |
(Malatión) |
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This fact sheet answers the
most frequently asked health questions about malathion.
For more information, you may call the ATSDR Information
Center at 1-888-422-8737. This fact sheet is one in
a series of summaries about hazardous substances and
their health effects. 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.
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HIGHLIGHTS: The general
population is probably not exposed to malathion
regularly. However, malathion is used to treat head
lice on humans, to kill fleas on pets, and to kill
insects in gardens. Exposure to malathion may also
occur at farms where it has been sprayed on crops.
Exposure to high amounts of malathion can cause
difficulty breathing, chest tightness, vomiting,
cramps, diarrhea, blurred vision, sweating, headaches,
dizziness, loss of consciousness, and possibly death.
This chemical has been found in at least 21 of the
1,636 National Priorities List sites identified
by the Environmental Protection Agency (EPA). |
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What
is malathion? |
Malathion is an insecticide that
does not occur naturally. Pure malathion is a colorless
liquid, and technical-grade malathion, which contains
>90% malathion and impurities in a solvent, is a
brownish-yellow liquid that smells like garlic. Malathion
is used to kill insects on farm crops and in gardens,
to treat lice on humans, and to treat fleas on pets.
Malathion is also used to kill mosquitos and Mediterranean
fruit flies (medflies) in large outdoor areas.
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What
happens to malathion when it enters the environment? |
- Malathion enters the environment primarily through
spraying on farm crops.
- Malathion does not stick to soil and is broken down
rapidly by bacteria in the soil, so it does not usually
move from the soil to groundwater.
- In water, malathion is broken down by the action
of the water and bacteria in the water.
- In air, malathion is broken down by sunlight.
- Malathion is not expected to accumulate in the food
chain due to rapid break down in aquatic organisms.
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How
might I be exposed to malathion? |
- Most people are not exposed to malathion in the
air they breathe or on things they touch, unless they
live next to areas being sprayed.
- Farm workers, chemical sprayers, and people who
work in factories that make malathion are most likely
to be exposed.
- People who use it around their homes and people
living in areas where malathion is sprayed to control
medflies or mosquitos may also be exposed.
- People who live near landfills where it has been
dumped may be exposed.
- Individuals may also be exposed by going into fields
too soon after spraying.
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How
can malathion affect my health? |
Malathion interferes with the normal
way that the nerves and brain function. Exposure to
very high levels of malathion for a short period in
air, water, or food may cause difficulty breathing,
chest tightness, vomiting, cramps, diarrhea, blurred
vision, sweating, headaches, dizziness, loss of consciousness,
and death. If persons who are exposed to high amounts
of malathion are rapidly given appropriate treatment,
there may be no long-term harmful effects. If people
are exposed to levels of malathion below those that
affect nerve function, few or no health problems seem
to occur.
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How
likely is malathion to cause cancer? |
There is no conclusive proof that
malathion causes cancer in humans, although some studies
have found increased incidence of some cancers in people
who are regularly exposed to pesticides, such as farmers
and pesticide applicators. Animal studies also fail
to provide conclusive evidence of carcinogenicity. The
International Agency for Research on Cancer (IARC) has
determined that malathion is unclassifiable as to carcinogenicity
to humans.
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How
can malathion affect children? |
It is likely that health effects
seen in children exposed to high levels of malathion
will be similar to the effects seen in adults. It is
not known whether children are more sensitive to the
effects of malathion than adults. There is some indication
that young rats may be more sensitive than adults to
nervous system effects.
Birth defects have not been observed
in humans exposed to malathion, but developmental effects
have been seen in the offspring of animals that ingested
enough malathion while pregnant to cause health effects
in the mother. Animal studies have shown that malathion
can be transferred from a pregnant mother to the developing
fetus and from a nursing mother to the newborns through
the mother's milk.
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How
can families reduce the risk of exposure to malathion? |
- The general population is not likely to be exposed
to large amounts of malathion. However, exposure may
be reduced by staying away from fields that have been
recently sprayed, by wearing protective clothing when
applying malathion around the home or in gardens,
and by washing fruits and vegetables grown in gardens
treated with malathion before eating. In areas where
malathion is sprayed to control medflies or mosquitos,
families can reduce exposure by remaining inside during
spraying periods, and by washing their hands and clothes
if they come in contact with sprayed surfaces within
a few days of the spraying.
- Children should avoid playing in soils near uncontrolled
hazardous waste sites where malathion may have been
discarded.
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Is
there a medical test to show whether I've been exposed
to malathion? |
Malathion can be detected in your
blood and its breakdown products can be detected in
your urine, but only within a few days after your last
exposure. If exposure is known or suspected, a test
can be done that measures cholinesterase levels in your
blood. Low levels of cholinesterase may be a result
of malathion exposure or may be caused by factors other
than malathion. These tests are not usually available
at your doctor's office, but your doctor can send the
samples to a laboratory that can perform the tests.
None of these tests, however, can predict whether you
will experience any health effects.
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Has
the federal government made recommendations to protect
human health? |
The EPA has established a level
of 0.1 milligrams of malathion per liter of drinking
water (0.1 mg/L) for lifetime exposure of adults as
a level that is not expected to cause effects that are
harmful to health.
The EPA allows a maximum of 0.1-135
parts (0.1-135 ppm) malathion per million parts of certain
types of food.
The Occupational Safety and Health
Administration (OSHA) has set a limit of 15 milligrams
of malathion per cubic meter of workplace air (15 mg/m³)
for 8 hour shifts and 40 hour work weeks.
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References |
Agency for Toxic Substances and
Disease Registry (ATSDR). 2001. Managing Hazardous Materials
Incidents. Volume III Medical Management Guidelines
for Acute Chemical Exposures: Malathion.
Atlanta, GA: U.S. Department of Health and Human Services,
Public Health Service.
Agency for Toxic Substances and
Disease Registry (ATSDR). 2003. Toxicological
Profile for malathion. Atlanta, GA: U.S. Department
of Health and Human Services, Public Health Service.
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Where can
I get more information? |
ATSDR can tell you where to find
occupational and environmental health clinics. Their
specialists can recognize, evaluate, and treat illnesses
resulting from exposure to hazardous substances. You
can also contact your community or state health or environmental
quality department if you have any more questions or
concerns. For more information, contact:
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Agency for Toxic Substances and Disease Registry
Division of Toxicology
1600 Clifton Road NE, Mailstop F-32
Atlanta, GA 30333
Phone: 1-888-42-ATSDR (1-888-422-8737)
FAX: (770)-488-4178
Email: ATSDRIC@cdc.gov
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