home edit2 whole TSD November 2002 PDF format - OEHHA

1, 1-DICHLOROETHANE
CAS No: 75-34-3
I. PHYSICAL AND CHEMICAL PROPERTIES (From HSDB, 1994)
Molecular weight 98.97
Boiling point 57.3°C (ATSDR, 1990)
Melting point -96.7°C (ATSDR, 1990)
Vapor pressure 230 mm Hg at 25°C (ATSDR, 1990)
Air concentration conversion 1 ppm = 4.05 mg/m 3
II.
HEALTH ASSESSMENT VALUES
Unit Risk Factor: 1.6 E-6 (µg/m 3 ) -1
Slope Factor: 5.7 E-3 (mg/kg-day) -1
[Female rat mammary gland adenocarcinoma tumor data (NCI, 1977), contained in Gold et al.
database (1990), expedited Proposition 65 methodology (Cal/EPA, 1992), cross-route
extrapolation.]
III.
CARCINOGENIC EFFECTS
Human Studies
No studies on the potential carcinogenic effects of 1,1-dichloroethane in humans are known to exist.
Animal Studies
Male and female Osborne-Mendel rats and B6C3F 1 mice were exposed to 1,1-dichloroethane
dissolved in corn oil by gavage (NCI, 1977). The study design is summarized in Tables 1a and 1b.
Dosing was performed once/day, 5 days/week. Dosing of the low- and high-dose mouse treatment
groups was performed cyclically in the latter part of the experimental period; one exposure-free week
was followed by 4 weeks of exposure.
Dose-related increases were noted in mammary adenocarcinomas and hemangiosarcomas in female
rats. Statistically significant increases were observed in endometrial stromal polyps in high-dose female
mice (4/46 compared to 0/79 for controls, p = 0.017) and in hepatocellular carcinomas in high-dose
male mice (8/32 compared to 6/72 in pooled vehicle controls, p = 0.027). Female rat tumor incidence
data is listed in Table 2.
Klaunig et al. (1986) exposed male B6C3F 1 mice to 1,1-dichloroethane in drinking water for 52
weeks. Exposure levels were 0, 835 and 2500 mg/l. Group sizes were 35 mice/group; 10 mice/group
were killed after 24 weeks. Histology was only performed on kidney, liver and lung samples. No
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