Abstract
A comparative study was made of the effect of pyrolysis at various temperatures upon the toxicity of aerosols of three aircraft engine hydraulic fluids. Rats and dogs were exposed 4 hours to both unpyrolyzed aerosols and aerosols pyrolyzed at 520°, 1020°, and 1560°F of the following fluids: OS-40, a phosphate ester; XF-408, a mixture of a silicone oil and a fluorohydrocarbon; and MLO-5277, an organosilicate. The toxic signs and pathologic changes produced in exposed animals showed that these compounds and their pyrolytic products were eye and respiratory irritants. OS-40 was the least toxic of the three fluids.