Abstract
The products from the thermal decomposition of carbon tetrachloride at its industrial threshold limit concentration of 10 ppm may be potentially hazardous, and possibly lethal, under some conditions. Phosgene, chlorine, chlorine dioxide, and hydrogen chloride were measured. Carbon tetrachloride vapors in contact with iron and glass surfaces decomposed at lower temperatures than when in contact with glass alone. A clean iron surface accelerated the decomposition of carbon tetrachloride and phosgene and the formation of chlorine; a “corroded” iron surface further accelerated these reactions, with less decomposition of phosgene. Humidity had very little effect on phosgene decomposition but significantly reduced the concentrations of chlorine and chlorine dioxide. Open flames, depending upon the degree of contact, may cause complete decomposition to hydrogen chloride. It is necessary to measure all of the decomposition products and to consider that their toxic effects may be additive.