Toxicity Profiles

RAGs A Format for Chloroform - CAS Number 67663

Chloroform is an organic, colorless liquid with a pleasant, nonirritating odor and a slightly sweet taste. It will burn only when it reaches very high temperatures. In the past, chloroform was used as an inhaled anesthetic during surgery, but the Food and Drug Administration banned the use of chloroform as an ingredient in human drug and cosmetic products in July 1976. Today, chloroform is used to make other chemicals and can also be formed in small amounts when chlorine is added to water. Chloroform is widely used as an intermediate in the production of refrigerants, plastics, and pharmaceuticals, and as a general solvent or constituent of solvent mixtures.

Chloroform is rapidly absorbed from the lungs and the digestive tract, and to some extent through the skin. Breathing about 900 parts of chloroform per million parts air (900 ppm) for a short time can cause dizziness, fatigue, and headache. Breathing air, eating food, or drinking water containing high levels of chloroform for long periods of time may damage your liver and kidneys. Large amounts of chloroform can cause sores when chloroform touches your skin. Animal studies have shown that miscarriages occurred in rats and mice that breathed air containing 30 to 300 ppm chloroform during pregnancy and also in rats that ate chloroform during pregnancy. Offspring of rats and mice that breathed chloroform during pregnancy had birth defects. Abnormal sperm were found in mice that breathed air containing 400 ppm chloroform for a few days.

Epidemiological studies indicate a possible relationship between exposure to chloroform present in chlorinated drinking water and cancer of the bladder, large intestine, and rectum. Based on U.S. EPA guidelines, chloroform was assigned to weight-of-evidence Group B2, probable human carcinogen. Rats and mice that ate food or drank water with chloroform developed cancer of the liver and kidneys.

The following is a presentation of the toxicity information associated with Chloroform.

Noncarcinogenic Health Effects
  • The Oral Chronic Reference Dose is 1.00E-02 (mg/kg-day).
  • The Oral Chronic Reference Dose has a modifying factor of 1.
  • The Oral Chronic Reference Dose has an uncertainty factor of 1000.
  • The Oral Chronic Reference Dose is based on the Heywood et al. study from 1979.
  • The Oral Chronic Reference Dose study target organ is liver.
  • The Oral Chronic Reference Dose study critical effect is fatty cyst formation.
  • The overall confidence in the Oral Chronic Reference Dose is medium.

  • The Dermal Chronic Reference Dose is 2.00E-03 (mg/kg-day).
  • The Dermal Chronic Reference Dose is based on a gastrointestinal absorption factor of 0.2000.

Carcinogenic Health Effects
  • The Oral Slope Factor is 6.10E-03 (mg/kg-day)-1.
  • The Oral Slope Factor study target organ is kidney.
  • The Oral Slope Factor study cancer type is tumors.
  • The Oral Slope Factor is based on the Jorgensen et al. study from 1985.

  • The Inhalation Unit Risk is 2.3E-02 (mg/m3)-1.
  • The Inhalation Unit Risk study target organ is liver.
  • The Inhalation Unit Risk study cancer type is carcinoma.
  • The Inhalation Unit Risk is based on the NCI study from 1976.

  • The Dermal Slope Factor is 3.05E-02 (mg/kg-day)-1.
  • The Dermal Slope Factor is based on a gastrointestinal absorption factor of 0.2000.