Accession Number : AD0751432

Title :   Continuous Animal Exposure to Methylene-Chloride,

Corporate Author : AEROSPACE MEDICAL RESEARCH LAB WRIGHT-PATTERSON AFB OHIO

Personal Author(s) : Haun,Charles C. ; Harris,Elliott S. ; Darmer,Kenneth I. , Jr

Report Date : DEC 1971

Pagination or Media Count : 12

Abstract : Dichloromethane, also known as methylene chloride, is used extensively as a solvent in many of the space cabin construction materials. The provisional space cabin limit has been set at 25 ppm for 90-day flights, and 5 ppm for 1000-day flights. To properly assess the inhalation hazard to astronauts, 2 high levels, 1000 and 5000 ppm, were intentionally selected and 4 animal species were exposed continuously to these concentrations for periods of not more than 14 weeks. The following observed changes were most significant: (1) Severe weight losses were observed in all species, most profound in dogs. (2) Dogs and monkeys continued to lose weight throughout the exposure or until death, and rats showed dose related subnormal growth rates when compared with controls. (3) At 5000 ppm dichloromethane, there were considerable deaths during the first 3 weeks; 50% in dogs, 25% in monkeys and 35% in mice. No rats died. At 1000 ppm exposure level, significant deaths occurred only in dogs when 6 died during the 6th and 7th weeks and the remaining 2 dogs became moribund. (4) Monkeys exposed to dichloromethane at 1000 ppm level for 14 weeks showed clinical signs of liver injury. (5) Rats showed no response at either exposure level other than growth depression. (6) Dogs that died exhibited gross lesions associated with hepatic failure.

Descriptors :   (*CHLORINE COMPOUNDS, *TOXICITY), SOLVENTS, SPACECRAFT CABINS, RESPIRATION, DOSAGE, PATHOLOGY, HEMATOLOGY, BLOOD CHEMISTRY, BODY WEIGHT, HISTOLOGY, LABORATORY ANIMALS, PROPELLANTS

Subject Categories : Toxicology

Distribution Statement : APPROVED FOR PUBLIC RELEASE