Acute inhalation toxicology of oxalyl chloride.

The acute inhalation LC50 of oxalyl chloride was determined in rats following a one-hour exposure. Four groups of 10 animals per group were exposed to a concentration range of 462-2233 ppm. One set of six animals was exposed to a concentration of oxalyl chloride of 1232 ppm for one hour to evaluate the histopathological change to the lungs. The LC50 is 1840 ppm with the 95% confidence interval between 1531 ppm and 2210 ppm. Microscopically, the lungs from the treated animals exhibited acute bronchiolitis, exudate within the alveoli, and congestion. Pulmonary edema appears to contribute significantly to mortality produced by oxalyl chloride. A comparison of the acute one-hour LC50 of oxalyl chloride to that of hydrogen chloride, phosgene, phosphorus oxychloride, boron trichloride, and chlorine indicates that it shares a comparable degree of acute toxicity to hydrogen chloride and is significantly less toxic via inhalation than the latter four chemicals.