Toxicity Profiles

RAGs A Format for 1,1,2-Trichloroethane - CAS Number 79005

1,1,2-Trichloroethane is a halogenated aliphatic hydrocarbon. 1,1,2-Trichloroethane is a nonflammable liquid with a pleasant odor that is insoluble in water and miscible with alcohol, ether, and many other organic liquids. 1,1,2-Trichloroethane is used in the manufacture of 1,1-dichloroethene; as a solvent for fats, waxes, natural resins, and alkaloids; and in organic synthesis. Small amounts of 1,1,2-trichloroethane are formed during the water chlorination process.

Very limited human data were available to evaluate the toxicity of 1,1,2-trichloroethane. 1,1,2-Trichloroethane is rapidly absorbed by the body. The chemical exerts a narcotic action at "low" concentrations and is irritating to the eyes and mucous membranes of the respiratory tract. When in contact with skin, 1,1,2-trichloroethane may cause cracking and erythema. No information is available on how breathing or swallowing 1,1,2-trichloroethane may affect human health. Applying 1,1,2-trichloroethane to the skin of a person resulted in stinging and burning of the skin. When animals breathed high levels of 1,1,2-trichloroethane, it affected the liver and kidneys. Nervous system effects, such as excitation and sleepiness, were also seen. When animals swallowed food or water containing 1,1,2-trichloroethane, effects on the stomach, blood, liver, kidneys, and nervous system were seen.

No epidemiologic studies or case reports addressing the carcinogenicity of 1,1,2-trichloroethane in humans were available. In a rodent bioassay, 1,1,2-trichloroethane was administered by gavage to rats and mice. No effects on tumor development were noted in rats. Treated mice had significantly increased incidences of hepatocellular carcinomas. An increased incidence of adrenal pheochromocytomas was also observed in male and female mice. In a cancer initiation/promotion study with rats, 1,1,2-trichloroethane did not exhibit tumor initiating or promoting activity. Based on EPA guidelines, 1,1,2-trichloroethane was assigned to weight-of-evidence group C, possible human carcinogen.

The following is a presentation of the toxicity information associated with 1,1,2-Trichloroethane.

• The Oral Chronic Reference Dose is 4.00E-03 (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 White et al. study from 1985.
• The Oral Chronic Reference Dose study critical effect is clinical serum chemistry.
• The overall confidence in the Oral Chronic Reference Dose is medium.

• The Dermal Chronic Reference Dose is 3.24E-03 (mg/kg-day).
• The Dermal Chronic Reference Dose is based on a gastrointestinal absorption factor of 0.8100.

• The Oral Slope Factor is 5.70E-02 (mg/kg-day)^-1.
• The Oral Slope Factor study target organ is liver.
• The Oral Slope Factor study cancer type is carcinoma.
• The Oral Slope Factor is based on the NCI study from 1978.

• The Inhalation Unit Risk is 1.6E-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 1978.

• The Dermal Slope Factor is 7.04E-02 (mg/kg-day)^-1.
• The Dermal Slope Factor is based on a gastrointestinal absorption factor of 0.8100.