September 1997 |
ToxFAQs™ |
for |
Methyl tert-Butyl Ether (MTBE) |
(Éter
metil tert-butílico (MTBE)) |
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This fact sheet answers the most frequently
asked health questions about methyl tert-butyl ether (MTBE).
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: Methyl tert-butyl
ether (MTBE) is a flammable liquid which is used as an
additive in unleaded gasoline. Drinking or breathing MTBE
may cause nausea, nose and throat irritation, and nervous
system effects. MTBE has been found in at least 11 of
the 1,430 National Priorities List sites identified by
the Environmental Protection Agency (EPA). |
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What
is methyl tert-butyl ether (MTBE)? |
Methyl tert-butyl ether (MTBE)
is a flammable liquid with a distinctive, disagreeable odor.
It is made from blending chemicals such as isobutylene and
methanol, and has been used since the 1980s as an additive
for unleaded gasolines to achieve more efficient burning.
MTBE is also used to dissolve gallstones.
Patients treated in this way have MTBE delivered directly
to their gall bladders through special tubes that are surgically
inserted.
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What
happens to methyl tert-butyl ether (MTBE) when it enters the
environment? |
- MTBE quickly evaporates from open containers and surface
water, so it is commonly found as a vapor in the air.
- Small amounts of MTBE may dissolve in water and get into
underground water.
- It remains in underground water for a long time.
- MTBE may stick to particles in water, which will cause
it to eventually settle to the bottom sediment.
- MTBE may be broken down quickly in the air by sunlight.
- MTBE does not build up significantly in plants and animals.
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How
might I be exposed to methyl tert-butyl ether (MTBE)? |
- Touching the skin or breathing contaminated air while
pumping gasoline.
- Breathing exhaust fumes while driving a car.
- Breathing air near highways or in cities.
- Drinking, swimming, or showering in water that has been
contaminated with MTBE.
- Receiving MTBE treatment for gallstones.
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How
can methyl tert-butyl ether (MTBE) affect my health? |
There is no evidence that MTBE causes
cancer in humans. One study with rats found that breathing
high levels of MTBE for long periods may cause kidney cancer.
Another study with mice found that breathing high levels of
MTBE for long periods may cause liver cancer.
The Department of Health and Human Services
(DHHS), the International Agency for Research on Cancer (IARC),
and the EPA have not classified MTBE as to its carcinogenicity.
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How
likely is methyl tert-butyl ether (MTBE) to cause cancer? |
There is no evidence that MTBE causes
cancer in humans. One study with rats found that breathing
high levels of MTBE for long periods may cause kidney cancer.
Another study with mice found that breathing high levels of
MTBE for long periods may cause liver cancer.
The Department of Health and Human Services
(DHHS), the International Agency for Research on Cancer (IARC),
and the EPA have not classified MTBE as to its carcinogenicity.
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Is
there a medical test to show whether I've been exposed to methyl tert-butyl ether (MTBE)? |
MTBE and its breakdown product, butyl
alcohol, can be detected in your breath, blood, or urine for
up to 1 or 2 days after exposure. These tests aren’t available
at most doctors’ offices, but can be done at special laboratories
that have the right equipment. There is no other test specific
to determining MTBE exposure.
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Has
the federal government made recommendations to protect human
health? |
The EPA has issued guidelines recommending
that, to protect children, drinking water levels of MTBE not
exceed 4 milligrams per liter of water (4 mg/L) for an
exposure of 1-10 days, and 3 mg/L for longer-term exposures.
The American Conference of Governmental
Industrial Hygienists (ACGIH) has recommended an exposure
limit of 40 parts of MTBE per million parts of air (40 ppm)
for an 8-hour workday, 40-hour workweek.
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Glossary |
Carcinogenicity: Ability to cause cancer.
CAS: Chemical Abstracts Service.
Evaporate: To change into a vapor or
gas.
Milligram (mg): One thousandth of a gram.
ppm: Parts per million.
Sediment: Mud and debris that have settled
to the bottom of a body of water.
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References |
Agency for Toxic Substances and Disease
Registry (ATSDR). 1996. Toxicological
Profile for methyl tert-butyl ether (MTBE). 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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