ToxFAQs

Methylene Chloride

CAS# 75-09-2

April 1993

Methylene Chloride CH2Cl2 Stereo Image XYZ File

NFPA Label Key Vermont SIRI MSDS Archive

Agency for Toxic Substances and Disease Registry

This fact sheet answers the most frequently asked health questions about methylene chloride. For more information, you may call the ATSDR Information Center at 1-800-447-1544. 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.

What is methylene chloride?
(Pronounced meth' i - leen klo' ride)

Methylene chloride is a colorless liquid with a mild, sweet odor. Another name for it is dichloromethane.

It does not occur naturally in the environment. It's made from methane gas or wood alcohol. It's widely used as a solvent in paint strippers, as a propellant in aerosols, and as a process solvent in the manufacturing of drugs. It's also used as a metal cleaning and finishing solvent.

Most methylene chloride gets in the environment from its use in industry and from home use of aerosols and paint removers. Because of concern over the health effects, its use in aerosols has declined.

Methylene chloride is approved as an extraction solvent for spices and hops. It used to be popular for removing caffeine from coffee, but most coffee producers no longer use it.

What happens to methylene chloride when it enters the environment?

• It evaporates very easily, so it's found mostly in air.
• More than 99 percent of the methylene chloride in air comes from industry and consumer products.
• It doesn't stick to soil particles or dissolve in water, so it moves from both soil and water to air.
• Soil and water organisms break it down to simpler compounds.
• Some drinking water has been shown to contain small amounts of methylene chloride.
• Plants and aquatic organisms do not appear to store it.

How might I be exposed to methylene chloride?

• Breathing workplace air where it is used
• Breathing fumes from paint strippers that contain it (check the label)
• Breathing fumes from aerosol cans that use it (check the label)
• Breathing contaminated air near waste sites.

How can methylene chloride affect my health?

Methylene chloride harms the human central nervous system.

High levels in the air (nearly 1,000 times average levels) may affect your ability to react fast, remain steady, or perform tasks that require precise hand movements. If you continue to breathe high levels, you may get:

• dizziness
• nausea
• tingling
• numbness in the fingers and toes.

In most cases, these effects will stop shortly after exposure ends. In animals, however, very high exposures have caused unconsciousness and death.

Exposure to lower levels of methylene chloride in air can lead to slightly impaired hearing and vision. Many people can smell methylene chloride at these lower levels. However, people differ in their ability to smell methylene chloride, so odors may not help you avoid an unwanted exposure.

In humans, direct skin contact with methylene chloride causes intense burning and mild redness of the skin. Direct contact with the eyes can burn the cornea. In animals that have been exposed to vapors or directly to methylene chloride, the cornea was damaged. The damage healed within a few days after the exposure ended.

How likely is methylene chloride to cause cancer?

The Department of Health and Human Services (DHHS) has determined that methylene chloride may reasonably be anticipated to be a carcinogen. Methylene chloride has not been shown to cause cancer in humans exposed to vapors in the workplace. However, breathing high concentrations of it for long periods did increase the incidence of cancer in mice.

Is there a medical test to show whether I've been exposed to methylene chloride?

Several tests measure exposure to methylene chloride. These tests are not routinely available in your doctor's office.

The most direct test measures methylene chloride in the air you breathe out. Your blood can also be tested to determine if methylene chloride is present. Since it stays in the blood a very short time, you must have these tests soon after exposure.

Doctors can also test urine for methylene chloride or for chemicals such as formic acid that are produced as methylene chloride breaks down in the body.

Has the federal government made recommendations to protect human health?

The Environmental Protection Agency (EPA) requires that releases of methylene chloride of 1,000 pounds or more be reported to the federal government. The EPA has guidelines as to how much of this chemical you may be exposed and for how long without harming your health. EPA recommends that children not drink water that contains more than 13.3 parts of methylene chloride per million parts of water (13.3 ppm) for longer than 1 day or with more than 1.5 ppm for longer than 10 days.

The Food and Drug Administration (FDA) has established limits on how much methylene chloride can remain in spice, hops extract, and decaffeinated coffee.

The Occupational Safety and Health Administration (OSHA) proposes to reduce the current occupational exposure limits to methylene chloride in air. The limit would go from 500 ppm to 25 ppm for an 8-hour workday.

The National Institute for Occupational Safety and Health (NIOSH) currently recommends a permissible limit of 75 ppm of methylene chloride in the air over a 10-hour workday in the presence of carbon monoxide concentrations less than or equal to 9.9 ppm.

Glossary

Carcinogen:

Substance that can cause cancer.

Cornea:

The clear front part of the eye.

PPM:

Parts per million.

Propellant:

The gas used in spray cans to force out the contents of the can.

References

Agency for Toxic Substances and Disease Registry (ATSDR). 1993. Toxicological profile for methylene chloride. Atlanta: U.S. Department of Health and Human Services, Public Health Service.

Agency for Toxic Substances and Disease Registry (ATSDR). 1990. Case studies in environmental medicine: Methylene chloride toxicity. Atlanta: U.S. Department of Health and Human Services, Public Health Service.

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:

Agency for Toxic Substances and Disease Registry

Division of Toxicology

1600 Clifton Road NE, Mailstop E-29

Atlanta, GA 30333

Phone: 1-800-447-1544

FAX: 404-639-6315

U.S. Department of Health and Human Services
Public Health Service
Agency for Toxic Substances and Disease Registry

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