PUBLIC HEALTH STATEMENT 

 Carbon Tetrachloride CAS#: 56-23-5 

Division of Toxicology August 2005

__________________________________________________________________________________________

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 

This Public Health Statement is the summary 

chapter from the Toxicological Profile for Carbon 

Tetrachloride. 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. 

_____________________________________ 

This public health statement tells you about carbon 

tetrachloride and the effects of exposure to it. 

The Environmental Protection Agency (EPA) 

identifies the most serious hazardous waste sites in 

the nation. These sites are then placed on the 

National Priorities List (NPL) and are targeted for 

long-term federal clean-up activities. Carbon 

tetrachloride has been found in at least 430 of the 

1,662 current or former NPL sites. Although the 

total number of NPL sites evaluated for this 

substance is not known, the possibility exists that 

the number of sites at which carbon tetrachloride is 

found may increase in the future as more sites are 

evaluated. This information is important because 

these sites may be sources of exposure and exposure 

to this substance may harm you. 

When a substance is released either from a large 

area, such as an industrial plant, or from a container, 

such as a drum or bottle, it enters the environment. 

Such a release does not always lead to exposure. 

You can be 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 carbon tetrachloride, many 

factors will determine whether you will 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 any other chemicals 

you are exposed to and your age, sex, diet, family 

traits, lifestyle, and state of health. 

1.1 WHAT IS CARBON TETRACHLORIDE? 

Carbon tetrachloride is a clear liquid that evaporates 

very easily. Most carbon tetrachloride that escapes 

to the environment is therefore found as a gas. 

Carbon tetrachloride does not easily burn. Carbon 

tetrachloride has a sweet odor, and most people can 

begin to smell it in air when the concentration 

reaches 10 parts carbon tetrachloride per million 

parts of air (ppm). It is not known whether people 

can taste it or, if they can, at what level. Carbon 

tetrachloride is a manufactured chemical and does 

not occur naturally in the environment, 

Carbon tetrachloride has been produced in large 

quantities to make refrigeration fluid and 

propellants for aerosol cans. Since many 

refrigerants and aerosol propellants have been found 

to affect the earth's ozone layer, the production of 

these chemicals is being phased out. Consequently, 

the manufacture and use of carbon tetrachloride has 

declined a great deal. 

In the past, carbon tetrachloride was widely used as 

a cleaning fluid (in industry and dry cleaning 

establishments as a degreasing agent, and in 
 PUBLIC HEALTH STATEMENT 

 Carbon Tetrachloride CAS#: 56-23-5 

Division of Toxicology August 2005

__________________________________________________________________________________________

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 

households as a spot remover for clothing, furniture, 

and carpeting). Carbon tetrachloride was also used 

in fire extinguishers and as a fumigant to kill insects 

in grain. Most of these uses were discontinued in 

the mid-1960s. Until recently, carbon tetrachloride 

was used as a pesticide, but this was stopped in 

1986. 

1.2 WHAT HAPPENS TO CARBON 

TETRACHLORIDE WHEN IT ENTERS 

THE ENVIRONMENT? 

Because carbon tetrachloride evaporates easily, 

most of the compound released to the environment 

during its production and use reaches the air, where 

it is found mainly as a gas. It can remain in air for 

several years before it is broken down to other 

chemicals. Small amounts of carbon tetrachloride 

are found in surface water. Because it evaporates 

easily, much of it will move from surface water to 

the air within a few days or weeks. However, it 

may be trapped in groundwater for longer periods. 

Carbon tetrachloride is not expected to stick to soil 

particles. If spilled onto the ground, much of it will 

evaporate to the air. Some of it may also go into 

groundwater, where it can remain for months before 

it is broken down to other chemicals. It is not 

expected to build up in fish. We do not know if it 

builds up in plants. 

1.3 HOW MIGHT I BE EXPOSED TO 

CARBON TETRACHLORIDE? 

Very low background levels of carbon tetrachloride 

are found in air, water, and soil because of past and 

present releases. Concentrations in air of 0.1 part 

carbon tetrachloride per billion parts of air (ppb) are 

common around the world, with somewhat higher 

levels often found (0.2–0.6 ppb) in cities. Carbon 

tetrachloride is also found in some drinking water 

supplies, usually at concentrations less than 0.5 ppb. 

Exposure to levels of carbon tetrachloride higher 

than these typical "background" levels is likely to 

occur only at specific industrial locations where 

carbon tetrachloride is still used or near chemical 

waste sites where emissions into air, water, or soil 

are not properly controlled. Exposure at such sites 

could occur by breathing carbon tetrachloride 

present in the air, by drinking water contaminated 

with carbon tetrachloride, or by getting soil 

contaminated with carbon tetrachloride on the skin. 

Young children may also be exposed if they eat soil 

that contains carbon tetrachloride. Carbon 

tetrachloride has been found in water or soil at 

about 26% of the waste sites investigated under 

Superfund, at concentrations ranging from less than 

50 to over 1,000 ppb. 

People who work with carbon tetrachloride are 

likely to receive the greatest exposure to the 

compound. The National Institute for Occupational 

Safety and Health (NIOSH) estimates that 58,208 

workers are potentially exposed to carbon 

tetrachloride in the United States. The average 

daily intake of carbon tetrachloride for the general 

population is estimated to be 0.1 microgram (μg per 

kg of body weight). The estimated average daily 

amount that the general population may drink in 

water is 0.01 μg per kg of body weight. 
 PUBLIC HEALTH STATEMENT 

 Carbon Tetrachloride CAS#: 56-23-5 

Division of Toxicology August 2005

__________________________________________________________________________________________

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 

1.4 HOW CAN CARBON TETRACHLORIDE 

ENTER AND LEAVE MY BODY? 

Carbon tetrachloride can enter your body through 

your lungs if you breathe air containing carbon 

tetrachloride, or through your stomach and 

intestines if you swallow food or water containing 

carbon tetrachloride. Carbon tetrachloride can also 

pass through the skin into the body. When you 

inhale carbon tetrachloride, over 30–40% of what 

you inhale enters your body, where most of it 

temporarily accumulates in body fat. Some can 

enter the kidney, liver, brain, lungs, and skeletal 

muscle. When you drink water contaminated with 

carbon tetrachloride, about 85–91% of it can enter 

your body. Much of the compound that enters your 

body when you breathe it or drink water 

contaminated with it leaves your body quickly, and 

a lot of it can be found in your breath within a few 

hours. Animal studies have shown that under 

differing conditions, 34–75% of carbon 

tetrachloride leaves the body in expired air, 20–62% 

leaves the body in feces, and only low amounts 

leave the body in the urine. Animal studies also 

suggest that it may take weeks for the remainder of 

the compound in the body to be eliminated, 

especially that which has entered the body fat. 

Most of the carbon tetrachloride is eliminated from 

your body unchanged, but some of it may be 

changed to other chemicals before removal from the 

body (for example, chloroform, hexachloroethane, 

and carbon dioxide). Chloroform and 

hexachloroethane may themselves cause harmful 

effects. 

1.5 HOW CAN CARBON TETRACHLORIDE 

AFFECT MY HEALTH? 

Scientists use many tests to protect the public from 

harmful effects of toxic chemicals and to find ways 

for treating persons who have been harmed. 

One way to learn whether a chemical will harm 

people is to determine how the body absorbs, uses, 

and releases the chemical. For some chemicals, 

animal testing may be necessary. Animal testing 

may also help identify health effects such as cancer 

or birth defects. Without laboratory animals, 

scientists would lose a basic method for getting 

information needed to make wise decisions that 

protect public health. Scientists have the 

responsibility to treat research animals with care 

and compassion. Scientists must comply with strict 

animal care guidelines because laws today protect 

the welfare of research animals. 

Most information on the health effects of carbon 

tetrachloride in humans comes from cases where 

people have been exposed to relatively high levels 

of carbon tetrachloride, either only once or for a 

short period, for example, by accidental poisoning 

or by working with the chemical in a confined space 

without ventilation. Experiments have not been 

performed on the effects of long-term exposure of 

humans to low levels of carbon tetrachloride, so the 

human health effects of such exposures are not 

known. 

The liver is especially sensitive to carbon 

tetrachloride since it contains a large amount of the 

enzymes that change the form of the chemical. 

Some of the breakdown products may attack cell 

proteins, interfering with the functions of the liver 
 PUBLIC HEALTH STATEMENT 

 Carbon Tetrachloride CAS#: 56-23-5 

Division of Toxicology August 2005

__________________________________________________________________________________________

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 

cells. Products that attack cell membranes may 

result in the death of the cells. In mild cases, the 

liver becomes swollen and tender, and fat builds up 

inside the organ. In severe cases, liver cells may be 

damaged or destroyed, leading to a decrease in liver 

function. Such effects are usually reversible if 

exposure is not too high or too long. 

The kidney is also sensitive to carbon tetrachloride. 

Less urine may be formed, leading to a buildup of 

water in the body (especially in the lungs) and 

buildup of waste products in the blood. Kidney 

failure often was the main cause of death in people 

who died after very high exposure to carbon 

tetrachloride. Long-term breathing exposure to 

carbon tetrachloride worsened age-related kidney 

disease in rats. 

Fortunately, if injuries to the liver and kidney are 

not too severe, these effects eventually disappear 

after exposure stops. This is because both organs 

can repair damaged cells and replace dead cells. 

Function usually returns to normal within a few 

days or a few weeks after the exposure has stopped. 

After exposure to high levels of carbon 

tetrachloride, the nervous system, including the 

brain, is affected. Such exposure can be fatal. The 

immediate effects are usually signs of intoxication, 

including headache, dizziness, and sleepiness 

perhaps accompanied by nausea and vomiting. 

These effects usually disappear within 1–2 days 

after exposure stops. In severe cases, stupor or even 

coma can result, and permanent damage to nerve 

cells can occur. 

Carbon tetrachloride also causes effects on other 

tissues of the body, but these are not usually as 

common or important as the effects on the liver, 

kidney, and brain. 

There have been no studies of the effects of carbon 

tetrachloride on reproduction in humans, but studies 

in rats showed that long-term inhalation may cause 

decreased fertility. 

Studies in animals have shown that swallowing or 

breathing carbon tetrachloride over a period of 

years increases the frequency of liver tumors. Mice 

breathing carbon tetrachloride also developed 

tumors of the adrenal gland. Studies have not been 

performed to determine whether swallowing or 

breathing carbon tetrachloride causes tumors in 

humans, but it should be assumed that carbon 

tetrachloride could produce cancer. The 

Department of Health and Human Services (DHHS) 

has determined that carbon tetrachloride may 

reasonably be anticipated to be a carcinogen (i.e., 

cause cancer). The International Agency for 

Research on Cancer (IARC) has classified carbon 

tetrachloride in Group 2B, possibly carcinogenic to 

humans. EPA has determined that carbon 

tetrachloride is a probable human carcinogen. 

Many reported cases of carbon tetrachloride toxicity 

are associated with drinking alcohol. The frequent 

drinking of alcoholic beverages increases the danger 

of organ damage from carbon tetrachloride 

exposure. This enhanced effect has been shown in 

situations in which a group of workers were 

exposed to carbon tetrachloride in air, but only 

those who were heavy consumers of alcohol 

became ill. 
 PUBLIC HEALTH STATEMENT 

 Carbon Tetrachloride CAS#: 56-23-5 

Division of Toxicology August 2005

__________________________________________________________________________________________

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 

1.6 HOW CAN CARBON TETRACHLORIDE 

AFFECT CHILDREN? 

This section discusses potential health effects in 

humans from exposures during the period from 

conception to maturity at 18 years of age. 

Children and adults may be exposed to low levels of 

carbon tetrachloride in drinking water. Small 

children who live near factories that produce or use 

carbon tetrachloride could accidentally eat some of 

the chemical by putting dirty hands in their mouths, 

but the amount of carbon tetrachloride in the soil is 

thought to be too low to be harmful. Carbon 

tetrachloride is no longer used in consumer 

products, but children could breathe in vapors if 

households are still using old supplies. 

It is not known if the way in which carbon 

tetrachloride is absorbed into and eliminated from 

the body is different in children than it is in adults, 

but the processes are likely to be similar. Compared 

to adults, young children have lower amounts of the 

enzyme that converts carbon tetrachloride to a 

harmful chemical. The health effects of carbon 

tetrachloride have not been studied in children, but 

they are likely to be similar to those seen in adults 

exposed to the chemical. 

There is no direct evidence that maternal exposure 

to carbon tetrachloride has a harmful effect on the 

fetus in humans. A few human survey-type studies 

suggest that maternal drinking water exposure to 

carbon tetrachloride might possibly be related to 

certain birth defects, such as low birthweight and 

small size at birth. Information from animal studies 

indicates that carbon tetrachloride may cause early 

fetal deaths, but does not cause birth defects in 

babies surviving to term. However, these animal 

studies did not test for neurological damage in 

exposed newborn babies. 

One study calculated that carbon tetrachloride is 

likely to pass from the maternal circulation into 

breast milk. Thus, it is possible that children could 

be exposed to carbon tetrachloride from breast 

feeding, but the levels of exposure are likely to be 

low. 

1.7 HOW CAN FAMILIES REDUCE THE 

RISK OF EXPOSURE TO CARBON 

TETRACHLORIDE? 

If your doctor finds that you have been exposed to 

substantial amounts of carbon tetrachloride, ask 

whether your children might also have been 

exposed. Your doctor might need to ask your state 

health department to investigate. 

Although most consumer uses of carbon 

tetrachloride have been banned, children may be 

exposed to carbon tetrachloride in old consumer 

household cleaning products. Removing these old 

containers will reduce your family’s risk of 

exposure to carbon tetrachloride. Household 

chemicals should be stored out of the reach of 

children to prevent accidental poisonings and skin 

burns. Always store household chemicals in their 

original containers. Never store household 

chemicals in containers that children would find 

attractive to eat and drink from, such as old soda 

bottles. Keep your poison control center’s number 

next to your phone. 
 PUBLIC HEALTH STATEMENT 

 Carbon Tetrachloride CAS#: 56-23-5 

Division of Toxicology August 2005

__________________________________________________________________________________________

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 

Sometimes older children sniff household chemicals 

in an attempt to get high. Your children may be 

exposed to carbon tetrachloride by intentionally 

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 CARBON 

TETRACHLORIDE? 

Several very sensitive and specific tests can detect 

carbon tetrachloride in exposed persons. The most 

convenient way is simply to measure carbon 

tetrachloride in exhaled air, but carbon tetrachloride 

can also be measured in blood, fat, or other tissues. 

Because special equipment is needed, these tests are 

not routinely performed in doctors' offices, but your 

doctor can refer you to where you can obtain such a 

test. Although these tests can show that a person 

has been exposed to carbon tetrachloride, the test 

results cannot be used to reliably predict whether 

any bad health effects might result. Because carbon 

tetrachloride leaves the body fairly quickly, these 

methods are best suited to detecting exposures that 

have occurred within the last several days. 

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. The EPA, the 

Occupational Safety and Health Administration 

(OSHA), and the Food and Drug Administration 

(FDA) are some federal agencies that develop 

regulations for toxic substances. Recommendations 

provide valuable guidelines to protect public health, 

but cannot be enforced by law. The Agency for 

Toxic Substances and Disease Registry (ATSDR) 

and the National Institute for Occupational Safety 

and Health (NIOSH) are two federal organizations 

that develop recommendations for toxic substances. 

Regulations and recommendations can be expressed 

as “not-to-exceed” levels, that is, levels of a toxic 

substance in air, water, soil, or food that do not 

exceed a critical value that is usually based on 

levels that affect animals; they are then adjusted to 

levels that will help protect humans. Sometimes 

these not-to-exceed levels differ among federal 

organizations because they used different exposure 

times (an 8-hour workday or a 24-hour day), 

different animal studies, or other factors. 

Recommendations and regulations are also updated 

periodically 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 carbon 

tetrachloride include the following: 

To protect the general public from exposure to 

carbon tetrachloride, the federal government has 

limited or banned the use of this compound in most 

common household products and fire extinguishers, 

and has discontinued its use as a pesticide. To 

protect workers who use carbon tetrachloride while 

on the job, the OSHA has set a maximum 

concentration limit in workplace air of 10 ppm for 

an 8-hour workday over a 40-hour work week. 

EPA has also set limits on how much carbon 

tetrachloride can be released from an industrial 

plant into waste water and is preparing to set limits 
 PUBLIC HEALTH STATEMENT 

 Carbon Tetrachloride CAS#: 56-23-5 

Division of Toxicology August 2005

__________________________________________________________________________________________

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 

on how much carbon tetrachloride can escape from 

an industrial plant into outside air. To ensure that 

drinking water supplies are safe, EPA has set a 

Maximum Contaminant Level (MCL) for carbon 

tetrachloride of 5 parts per billion (ppb), based on 

analytical detection limits in drinking water. 

Because carbon tetrachloride is possibly 

carcinogenic to humans, a Maximum Contaminant 

Level Goal (MCLG) of zero has been proposed. 

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, your regional 

Nuclear Regulatory Commission office, or contact 

ATSDR at the address and phone number below. 

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. 

Toxicological profiles are also available on-line at 

www.atsdr.cdc.gov and on CD-ROM. You may 

request a copy of the ATSDR ToxProfiles 

CD-ROM by calling the information and technical 

assistance toll-free number at 1-888-42ATSDR 

(1-888-422-8737), by email at atsdric@cdc.gov, or 

by writing to: 

Agency for Toxic Substances and Disease Registry 

Division of Toxicology 

 1600 Clifton Road NE 

 Mailstop F-32 

 Atlanta, GA 30333 

 Fax: 1-770-488-4178 

For-profit organizations may request a copy of final 

profiles from the following: 

National Technical Information Service (NTIS) 

 5285 Port Royal Road 

 Springfield, VA 22161 

 Phone: 1-800-553-6847 or 1-703-605-6000 

 Web site: http://www.ntis.gov/