Mutagenicity and toxicity studies with high pressure nitrous oxide.

The mutagenic and toxic potential of nitrous oxide were assessed in vitro by microbial assay using two histidine dependent strains of Salmonella typhimurium, TA98 and TA100. Bacteria on plates and in liquid suspension in the presence or absence of enzymes prepared from rat liver, were exposed in a pressure chamber to partial pressures of nitrous oxide ranging from 0.5 to 6 atmospheres. Nitrous oxide decreased viability of both strains of bacteria at 4 and 6 atmospheres but was not mutagenic at any pressure tested.