1,1,2,2-Tetrachloroethane

CAS RN:79-34-5

Toxicity Summary

IDENTIFICATION AND USE: 1,1,2,2-Tetrachloroethane is a volatile synthetic chemical that is used as intermediate in the synthesis of other chlorinated hydrocarbons. HUMAN EXPOSURE AND TOXICITY: Intoxications have been fatal. Central nervous system and the liver are the target tissues in acute exposures. Liver, gastro-intestinal tract and nervous system (central peripheral) are the targets in chronic exposure. Toxic effects are also reported in the hematopoietic system. Acute and chronic exposures produce jaundice, liver enlargement, fatty degeneration, hepatic necrosis, and cirrhosis. Respiratory irritation and pulmonary edema may follow inhalation exposures. Skin contact may result in dryness, scaling, and inflammation. Severe lesions may occur. Eye contact may result in burning and serious eye damage. Inhalation may cause a burning sensation, wheezing, coughing, laryngitis, and shortness of breath. Ingestion may cause diarrhea and severe mucosal injury. Numerous deaths due to its ingestion, inhalation and cutaneous absorption have been recorded. The solvent effects primarily the central nervous system and the liver and caused polyneuritis and paralysis. Of 380 workers exposed to the solvent 133 (35%) exhibited tremor and other nervous symptoms. Accidental and occupational exposure produced liver damage, ranging from severe fatty degeneration to necrosis and acute atrophy, which was frequently fatal, and gastrointestinal disorders; toxic effects were also observed in the hematopoietic system. In case of emergency, it is important to wash skin with soap and water after removing contaminated clothing. Like others of this class, 1,1,2,2-tetrachloroethane could generate some hyperexcitability of the heart. The prognosis following intoxication with this chemical is that rapid progression of jaundice indicates a poor outcome. In some instances, mild symptoms will persist up to 3 months and then progress to acute yellow atrophy and death. Anuria may persist for as long as 2 weeks and still be followed by complete recovery. ANIMAL STUDIES: The acute toxicity of 1,1,2,2-tetrachloroethane in experimental animals is slight to moderate. The liver appears to be the most sensitive target organ. Minimal effects on the liver (reversible increase in lipid content) and other endpoints (an increase in levels of adrenocorticotropic hormone and reversible alteration in hematological parameters) have been observed in rats exposed to 13.3 mg/cu m for up to nine months. Reproductive and developmental effects have been observed in experimental animals only at doses that caused reductions in body weight. Long term ingestion of this chemical resulted in increased incidences of liver tumors in both male and female mice. However, similar exposure was not associated with a significant increase in tumors at any site in rats, although both species were exposed only for up to 78 wk. Based on the results of available in vivo and in vitro assays, 1,1,2,2-tetrachloroethane has, at most, weak genotoxic potential. 1,1,2,2-Tetrachloroethane was a potent promoter, but not an initiator, of gamma-glutamyltranspeptidase positive foci in the liver of rats. The profile for tumor induction by 1,1,2,2-tetrachloroethane is similar to that of dichloroacetic acid, its primary metabolite. ECOTOCITY STUDIES: Exposure to 1,1,2,2-tetrachloroethane has been demonstrated to inhibit the activities of environmental bacteria (lowest reported IC50 was 1.4 mg/L) and cause immobilization of Daphnia magna (48 hr EC50 values of 23 mg/L and above). In fresh water fish species, the lowest LC50 (96 hr) was 18.5 mg/L in flagfish (Jordanella floridae), where the lowest observed effect concentration (LOEC) for longer term exposure was 7.2 mg/L, which resulted in reduced larval survival in the same species.I
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