Health Concerns

Chloroform

One way chloroform enters the body is by inhalation of contaminated air into the lungs. Chloroform is absorbed readily into the body when inhaled. Chloroform can quickly enter the blood stream from the lungs or intestines. Once in the blood, it is carried to all parts of the body, such as the liver or kidneys. Chloroform usually collects in body fat and is metabolized in the kidney and excreted through the lungs (unchanged) or through the urine and feces. Some of the chloroform that enters the body is broken down into other chemicals. These chemicals, or breakdown products, can attach to other chemicals inside the cells of the body and may cause harmful effects if they collect in high enough amounts in the body. Some of the breakdown products can also leave the body through exhaled air. Only a small amount of the breakdown products leaves the body in the urine or feces (ATSDR, 1995).

Exposure to chloroform in the environment from the ambient air is a health concern because of a potential to induce cancer from chronic exposure and possible additivity with other sources of chloroform in daily life. In humans, large amounts of inhaled chloroform can affect the central nervous system (brain), liver, and kidneys. At very high concentrations chloroform has been used as an anesthetic agent in man. This use was discontinued as safer agents became available. Breathing about 900 ppm (4000 ug/m 3 ) for a short time causes fatigue, dizziness, and headache. At lesser concentrations over a long period of time, chloroform may damage the liver and kidneys. At lesser concentrations chloroform has produced reproductive effects in animals such as birth defects and abnormal sperm. It is not known whether these effects would occur in humans.

Most chloroform in the air eventually breaks down, but this process is slow. The breakdown products in air include phosgene, which is more toxic than chloroform, and hydrogen chloride, which is also toxic (ATSDR, 1995).

Studies of people who drank chlorinated water showed a possible link between chloroform formed in the water and cancer of the colon and urinary tract. Animals which received similar exposures for longer periods of time developed liver and kidney tumors.

Because chloroform is absorbed rapidly and eliminated relatively slowly there is concern for chronic and periodic exposures from ambient air. The presence of chloroform in other media such as food and water raises concern for multi pathway exposures. The total dose from all sources of chloroform would need to be taken into account when considering the health hazard. Because the compound is metabolized before removal from the body some persons could be more sensitive to chloroform than the general public. Those of particular concern would include the young, the elderly, those who are pregnant and those with liver disease or taking drugs that could affect the liver.

Chloroform has been classified as Class B2: Probable Human Carcinogen by the United States Environmental Protection Agency and as a Group 2B: Possible Human Carcinogen by the International Agency for Research on Cancer.

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Last Updated: 1/31/03