home edit2 whole TSD November 2002 PDF format - OEHHA

1,1,2,2-TETRACHLOROETHANE
CAS No: 79-34-5
I. PHYSICAL AND CHEMICAL PROPERTIES (From HSDB, 1994)
Molecular weight 167.9
Boiling point
146.5ºC
Melting point
-44ºC
Vapor pressure 9 mm Hg @ 30ºC
Air concentration conversion 1 ppm = 6.87 mg/m 3
II.
HEALTH ASSESSMENT VALUES
Unit Risk Factor: 5.8 E-5 (µg/m 3 ) -1
Slope Factor: 2.0 E-1 (mg/kg-day) -1
[Calculated by US EPA from NCI (1978) female mouse hepatocellular carcinoma tumor data
using a linearized multistage procedure, extra risk]
III.
CARCINOGENIC EFFECTS
Human Studies
Norman et al. (1981) studied Army personnel assigned to treat chemical warfare protective equipment
with material dissolved in tetrachloroethane. Of 3859 workers assigned to this process, 1099 whites
and 124 blacks had probable exposure to the solvent. No statistically significant excess cancer
mortality was noted. Slight excesses were noted for leukemia (SMR = 272, based on 4 deaths) and
cancer of the genital organs (SMR = 158, based on 3 deaths).
Animal Studies
Theiss et al. (1977) exposed groups of 20 male A/st mice to 1,1,2,2-tetrachloroethane in tricaprylin by
intraperitoneal injection (3/week) at doses of 80 mg/kg body weight, 200 mg/kg or 400 mg/kg. All
survivors (10, 15 and 5 at the three doses, respectively) were killed 24 weeks after the first injection.
The average number of tumors/animal were not significantly increased in the treated mice (0.3, 0.5 and
1.0 at the three doses, respectively compared to 0.27 for controls). However, the poor survival of
treated animals and inadequate length of observation made this study unusable for a determination of the
carcinogenicity of 1,1,2,2-tetrachloroethane.
B6C3F 1 mice (50 male, 50 female) were treated with technical grade (90% pure) 1,1,2,2-
tetrachloroethane in corn oil by gavage 5 days/week (NCI, 1978). Low-dose and high-dose mice
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