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PUBLIC HEALTH STATEMENT 

METHYLENE CHLORIDE 

CAS#: 75-09-2 

Division of Toxicology September 2000 

This Public Health Statement is the summary 

chapter from the Toxicological Profile for 

Methylene Chloride. It is one in a series of Public 

Health Statements about hazardous substances and 

their health effects. A shorter version, the 

ToxFAQsTM, 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. 

1.1 WHAT IS METHYLENE CHLORIDE? 

Methylene chloride, also known as 

dichloromethane, is a colorless liquid that has a 

mild sweet odor, evaporates easily, and does not 

burn easily. It is widely used as an industrial 

solvent and as a paint stripper. It can be found in 

certain aerosol and pesticide products and is used in 

the manufacture of photographic film. The 

chemical may be found in some spray paints, 

automotive cleaners, and other household products. 

Methylene chloride does not appear to occur 

naturally in the environment. It is made from 

methane gas or wood alcohol. Most of the 

methylene chloride released to the environment 

results from its use as an end product by various 

industries and the use of aerosol products and paint 

removers in the home. 

1.2 WHAT HAPPENS TO METHYLENE 

CHLORIDE WHEN IT ENTERS THE 

ENVIRONMENT? 

Methylene chloride is mainly released to the 

environment in air, and to a lesser extent in water 

and soil, due to industrial and consumer uses. 

Many chemical waste sites, including NPL sites, 

contain methylene chloride and these might act as 

additional sources of environmental contamination 

through spills, leaks, or evaporation. Because 

methylene chloride evaporates readily, most of it is 

released into the air. In the air, it is broken down by 

sunlight and by reaction with other chemicals 

present in the air. About half of the methylene 

chloride disappears from air in 53 to 127 days. 

Although methylene chloride does not dissolve 

easily in water, small amounts may be found in 

some drinking water. Methylene chloride that is 

present in water is broken down slowly by reactions 

with other chemicals or by bacteria. Over 90% of 

the methylene chloride in the environment changes 

to carbon dioxide (CO2), which is already present in 

air. It takes about 1 to 6 days for half the methylene 

chloride to break down in water. When methylene 

chloride is spilled on land, it attaches loosely to 

nearby surface soil particles. It moves from the soil 

into the air. Some may also move into 

groundwater. We do not know how long it remains 

in soil. We do not expect methylene chloride to 

build up in plants or animals. 

1.3 HOW MIGHT I BE EXPOSED TO 

METHYLENE CHLORIDE? 

You may be exposed to methylene chloride in air, 

water, food, or from consumer products. Because 

methylene chloride evaporates easily, the greatest 

potential for exposure is when you breathe vapors 

DEPARTMENT of HEALTH AND HUMAN SERVICES, Public Health Service
 

Agency for Toxic Substances and Disease Registry 

www.atsdr.cdc.gov/ Telephone: 1-888-422-8737 Fax: 770-488-4178 E-Mail: atsdric@cdc.gov 
 

 

 

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PUBLIC HEALTH STATEMENT 

METHYLENE CHLORIDE 

CAS#: 75-09-2 

Division of Toxicology September 2000 

of contaminated air. Background levels in air are 

usually at less than one part methylene chloride per 

billion parts (ppb) of air. Methylene chloride has 

been found in some urban air and at some 

hazardous waste sites at average concentrations of 

11 ppb of air. The average daily intake of 

methylene chloride from outdoor air in three U.S. 

cities ranges from 33 to 309 micrograms per day (1 

milligram is equivalent to 1,000 micrograms, 1 mg 

= 1,000 μg.). Contact with consumer products such 

as paint strippers or aerosol cans that contain 

methylene chloride is another frequent source of 

exposure. Exposure occurs as a result of breathing 

the vapors given off by the product or from direct 

contact of the liquid material with the skin. The 

highest and most frequent exposures to methylene 

chloride usually occur in workplaces where the 

chemical is used; exposure can be dangerously high 

if methylene chloride is used in an enclosed space 

without adequate ventilation. People who work 

with it can breathe in the chemical or it may come 

in contact with their skin. In the past, 

concentrations ranging from 1 to 1,000 parts of 

methylene chloride per million parts of air (ppm; 1 

ppm is 1,000 times more than 1 ppb) have been 

detected in general work areas, while higher 

concentrations (1,400 ppm) have been detected in 

samples in the breathing zone of some workers. 

These exposure levels exceed the current 

recommended federal limits. The National Institute 

for Occupational Safety and Health (NIOSH) 

estimated that 1 million workers may be exposed to 

methylene chloride. Averages of 68 ppb of 

methylene chloride in surface water and 98 ppb 

methylene chloride in groundwater have been found 

at some hazardous waste sites. Less than 1 ppb has 

been found in most drinking water analyzed. We 

expect exposure from water and food to be low 

because very little methylene chloride has been 

detected in these sources. 

1.4 HOW CAN METHYLENE CHLORIDE 

ENTER AND LEAVE MY BODY? 

Methylene chloride may enter your body when you 

breathe vapors of contaminated air. It may also 

enter your body if you drink water from 

contaminated wells, or it may enter if your skin 

comes in contact with it. Since methylene chloride 

evaporates into air rapidly, exposure by breathing is 

the most likely source of exposure at hazardous 

waste sites, in the home, and in the workplace. 

When you breathe in methylene chloride, over 70% 

of it enters your bloodstream and quickly spreads 

throughout your body, with most of it going to the 

liver, kidney, brain, lungs, and fatty tissue. 

Increased physical activity or an increased amount 

of body fat tends to increase the amount of 

methylene chloride that remains or accumulates in 

your body tissue. About half of the methylene 

chloride in the blood leaves within 40 minutes. 

Some of the methylene chloride is broken down into 

other chemicals, including carbon monoxide (CO), 

a natural substance in the body occurring from the 

breakdown of hemoglobin. Unchanged methylene 

chloride and its breakdown products are removed 

from your body mainly in the air you breathe out. 

Small amounts leave in your urine. This usually 

occurs within 48 hours after exposure. Although 

the rate of uptake through the stomach has not been 

measured, uptake is likely to be fast. Skin 

absorption is usually small. Trapping the chemical 

against the skin with clothing or gloves can lead to 

greater absorption and possible chemical burns. 

DEPARTMENT of HEALTH AND HUMAN SERVICES, Public Health Service
 

Agency for Toxic Substances and Disease Registry 

www.atsdr.cdc.gov/ Telephone: 1-888-422-8737 Fax: 770-488-4178 E-Mail: atsdric@cdc.gov 
 

 

 

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PUBLIC HEALTH STATEMENT 

METHYLENE CHLORIDE 

CAS#: 75-09-2 

Division of Toxicology September 2000 

1.5 HOW CAN METHYLENE CHLORIDE 

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. 

If you breathe large amounts (800 ppm) of 

methylene chloride you may not be able to react 

fast, remain steady, or perform tasks requiring 

precise hand movements. You may experience 

dizziness, nausea, tingling or numbness of the 

fingers and toes, and drunkenness if you breathe 

methylene chloride for a sufficiently long period of 

time. In most cases, effects disappear shortly after 

the exposure ends. Studies in animals suggest that 

exposure to higher concentrations (8,000–20,000 

ppm) can lead to unconsciousness and death. There 

have been reports of some people becoming 

unconscious and some people dying after breathing 

high concentrations of methylene chloride; 

accidents of this kind happen more often when 

methylene chloride is used without adequate 

ventilation. 

Breathing methylene chloride may cause changes in 

the liver and kidney in animals, but similar effects 

have not been observed in humans. Animal studies 

indicate that should you be exposed to high levels 

of vapors of methylene chloride in air, the vapors 

may irritate your eyes and affect your cornea. One 

study reported these effects at concentrations of 490 

ppm; however, the effects usually disappeared 

within a few days. 

In humans, direct skin contact with large amounts 

of methylene chloride causes intense burning and 

mild redness of the skin. In a workplace accident in 

which a person was found to have lost 

consciousness and partly fallen into an open vat of 

methylene chloride, extended direct contact with the 

liquid caused severe burns of the skin and eyes 

(cornea); these conditions were treatable. In 

rabbits, effects were observed on the eyes (e.g., 

cornea), but they were reversible within a few days. 

People can smell methylene chloride at about 200 

ppm in air. After about 3 hours of exposure at this 

level, a person will become less attentive and less 

accurate in tasks that require hand-eye coordination. 

Because people differ in their ability to smell 

various chemicals, odors may not be helpful in 

avoiding over-exposure to methylene chloride. 

There is not clear evidence that methylene chloride 

causes cancer in humans exposed to vapors in the 

workplace. However, breathing high concentrations 

of methylene chloride for long periods of time did 

increase the incidence of cancer in mice. No 

information was found regarding the cancer-causing 

effects of methylene chloride in humans after oral 

exposure. The Department of Health and Human 

Services (DHHS) has determined that methylene 

chloride may reasonably be anticipated to be a 

DEPARTMENT of HEALTH AND HUMAN SERVICES, Public Health Service
 

Agency for Toxic Substances and Disease Registry 

www.atsdr.cdc.gov/ Telephone: 1-888-422-8737 Fax: 770-488-4178 E-Mail: atsdric@cdc.gov 
 

 

 

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PUBLIC HEALTH STATEMENT 

METHYLENE CHLORIDE 

CAS#: 75-09-2 

Division of Toxicology September 2000 

cancer-causing chemical. The International Agency 

for Research on Cancer (IARC) has classified 

methylene chloride in Group 2B, possibly causing 

cancer in humans. The EPA has determined that 

methylene chloride is a probable cancer-causing 

agent in humans. 

1.6 HOW CAN METHYLENE CHLORIDE 

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 and adults may be exposed to low levels of 

methylene chloride in drinking water. Small 

children who live near factories that produce or use 

methylene chloride could accidently eat some of the 

chemical by putting dirty hands in their mouths, but 

the amount of methylene chloride in the soil is 

thought to be too low to be harmful. Children could 

breathe in methylene chloride that is used in a 

number of household products, since it evaporates 

easily. Also, since the vapor of methylene chloride 

is heavier than air, it will tend to stay close to the 

ground; as a result, children, being shorter, would 

breathe in larger amounts than adults during 

accidental exposure. 

The effects of methylene chloride have not been 

studied in children, but they would likely 

experience the same health effects seen in adults 

exposed to the chemical. It is also not known if the 

way in which methylene chloride is absorbed, 

metabolized, and eliminated from the body is 

different in children than it is in adults. Therefore, 

adverse effects noted in animals and adult humans 

(as discussed in Section 1.5) might also occur in 

children. 

There have not been any reports of a connection 

between methylene chloride exposure during 

pregnancy and birth defects in humans. If a 

pregnant woman is exposed to methylene chloride, 

a small amount may cross the placenta, but not 

enough to harm the fetus. Studies in animals show 

that breathing methylene chloride at relatively high 

levels during pregnancy may lead to bone 

variations, none of which are serious and some of 

which may be outgrown, in newborn pups. 

Methylene chloride has been shown to cross the 

placenta in rats. Methylene chloride has not been 

accurately measured in human milk and there are no 

animal studies testing to what extent it can pass into 

milk. 

1.7 HOW CAN FAMILIES REDUCE THE 

RISK OF EXPOSURE TO METHYLENE 

CHLORIDE? 

If your doctor finds that you have been exposed to 

significant amounts of methylene chloride, ask 

whether your children might also be exposed. Your 

doctor might need to ask your state health 

department to investigate. 

Children may be exposed to methylene chloride in 

consumer household products, such as paint 

removers, which contain a large percentage of 

methylene chloride. In general, the amounts of 

methylene chloride in consumer products are low 

and children are not likely to be harmed unless large 

amounts contact the skin or are accidentally 

swallowed. Using paint removers, especially in 

unventilated or poorly ventilated areas, may cause 

the amount of methylene chloride in the air to reach 

potentially dangerous levels. Caution should be 

used when using paint removers inside your house; 

you should follow instructions on the package label 

DEPARTMENT of HEALTH AND HUMAN SERVICES, Public Health Service
 

Agency for Toxic Substances and Disease Registry 

www.atsdr.cdc.gov/ Telephone: 1-888-422-8737 Fax: 770-488-4178 E-Mail: atsdric@cdc.gov 
 

 

 

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PUBLIC HEALTH STATEMENT 

METHYLENE CHLORIDE 

CAS#: 75-09-2 

Division of Toxicology September 2000 

for the proper ventilation conditions when using 

these products. It is also advisable to make certain 

that children do not remain near indoor paint 

removal activities. 

Household chemicals should be stored out of reach 

of young children to prevent accidental poisonings 

or skin irritation. Always store household 

chemicals in their original labeled containers. 

Never store household chemicals in containers that 

children would find attractive to eat or drink from, 

such as old soda bottles. Keep your Poison Control 

Center’s number next to the phone. 

Sometimes older children sniff household chemicals 

in an attempt to get high. Your children may be 

exposed to methylene chloride by inhaling products 

containing it. Talk with your children about the 

dangers of sniffing chemicals. 

1.8 IS THERE A MEDICAL TEST TO 

DETERMINE WHETHER I HAVE BEEN 

EXPOSED TO METHYLENE CHLORIDE? 

Several tests exist for determining whether you 

have had measurable exposure to methylene 

chloride. The most direct method measures 

methylene chloride in the air you breathe out. Your 

blood can also be analyzed to determine if 

methylene chloride is present. However, these tests 

are only useful for detecting exposures which have 

occurred within a few days because methylene 

chloride remains in the blood for a very short time. 

Some absorbed methylene chloride is stored in fat 

and slowly returns to the bloodstream. A test to 

measure carboxyhemoglobin (COHb), a chemical 

formed in blood as methylene chloride breaks down 

in the body, can also be used as an indicator of 

exposure. However, this test is not specific, since 

smoking and exposure to other chemicals may also 

increase COHb levels. Your urine can also be 

tested for methylene chloride itself or for other 

chemicals (such as formic acid) that are produced as 

methylene chloride breaks down in the body. These 

tests are not routinely available in a doctor's office, 

and they require special equipment. Also, the test 

for formic acid is not specific for methylene 

chloride, since other chemicals, such as 

formaldehyde, are broken down to formic acid. The 

tests may be useful to determine exposure to 

methylene chloride but do not by themselves 

measure or predict health effects. 

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 

DEPARTMENT of HEALTH AND HUMAN SERVICES, Public Health Service
 

Agency for Toxic Substances and Disease Registry 

www.atsdr.cdc.gov/ Telephone: 1-888-422-8737 Fax: 770-488-4178 E-Mail: atsdric@cdc.gov 
 

 

 

 

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PUBLIC HEALTH STATEMENT 

METHYLENE CHLORIDE 

CAS#: 75-09-2 

Division of Toxicology September 2000 

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 methylene chloride include 

the following: 

The EPA requires that releases of methylene 

chloride of 1,000 pounds or more be reported to the 

federal government. The EPA has provided 

guidelines on how much methylene chloride you 

may be exposed to for certain amounts of time 

without causing risk to human health. It 

recommends that exposure of children to methylene 

chloride in drinking water should not exceed 10 

milligrams/liter (mg/L) for 1 day or 2 mg/L for 10 

days. 

Because methylene chloride is used in processing 

spices, hops extract, and decaffeinated coffee, the 

FDA has established limits on the amounts of 

methylene chloride that can remain in these food 

products. 

The OSHA currently has a “permissible exposure 

limit” (PEL) of 25 ppm for an 8-hour workday with 

125 ppm as a “short-term exposure limit” (STEL) 

for 15 minute durations for persons who work with 

methylene chloride. 

NIOSH no longer has a “recommended exposure 

limit” (REL) for methylene chloride. Because 

methylene chloride causes tumors in some animals, 

NIOSH currently considers it a possible cancercausing substance in the workplace and 

recommends that exposure be lowered to the lowest 

feasible limit. 

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: 1-888-42-ATSDR (1-888-422-8737) 

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 

Reference 

Agency for Toxic Substances and Disease Registry 

(ATSDR). 2005. Toxicological profile for 

Methylene Chloride. Atlanta, GA: U.S. Department 

of Health and Human Services, Public Health 

Service. 

DEPARTMENT of HEALTH AND HUMAN SERVICES, Public Health Service
 

Agency for Toxic Substances and Disease Registry 

www.atsdr.cdc.gov/ Telephone: 1-888-422-8737 Fax: 770-488-4178 E-Mail: atsdric@cdc.gov