Human Exposure to 1,1,1-Trichloroethane Vapor: Relationship of Expired Air and Blood Concentrations to Exposure and Toxicity

Abstract

A study of controlled human exposures to 1, 1, 1-trichloroethane vapor has revealed a prolonged exponential “decay curve” when the concentration in the postexposure expired air is plotted against hours after exposure. This measurement was predictable enough to allow a reasonable estimation of the magnitude of exposure. Chemical, physiological, and clinical laboratory studies were carried out and correlated with the vapor exposures. The determination of urinary urobilinogen proved to be the most sensitive test of liver stress produced by markedly excessive exposures to 1,1,1-trichloroethane. Data from this study support 500 ppm as a satisfactory threshold limit for this compound.