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633983 
Book/Book Chapter 
Hexachloroethane 
American Conference of Governmental Industrial Hygienists :: ACGIH 
1991 
American Conference of Governmental Industrial Hygienists 
Cincinnati, OH 
Documentation of the threshold limit values and biological exposure indices 
II 
741-744 
TLV Recommendation
Results ofWeeks'(2) inhalation study with HCE suggest a steep dose-response curve. Repeated exposures at 260 ppm produced obvious signs of toxicity, including some mortality in rats, dogs, and guinea pigs, while concentrations of 48 ppm produced respiratory irritation but no other signs of toxicity to any of the three species exposed. Dietary administration of HCE to rats for 16 weeks resulted in kidney and liver injury.(7) The lowest effect level by the dietary route (15 mg/kg/day), which
caused microscopic kidney changes in male rats, can be calculated to be approximately equivalent to 105 mg/m3 or 10.5 ppm if inhaled by workers for a normal workday. The NOELof 1 mg/kg/day approximates an inhaled concentration of7 mg/m3 (0.7 ppm). Results from thedietary
studies prompted the TLVCommittee in 1989 to recommend the current TLV-TWA of 1 ppm (9.7 mg/m3) to protect against liverand kidney injury, in lightof the latest NTP study(10) anditsreported evidence ofHCE's carcinogenic activity in male rats, the TLV Committee in 1990
recommended the addition of an A2 designation (suspected human carcinogen) based on limited evidence of carcinogenicity in experimental animals; the substance was listed on the Notice of Intended Changes for 1990-1991 . 
Sixth