Inhalation Toxicity of Pyrolysis Products of Monobromomonochloromethane (Cb) and Monobromotrifluoromethane (CBRF3)

摘要

The toxicities of the pyrolysis products of two fire extinguishant compounds, CH2ClBr and CBrF3, were investigated using albino rats and 14 day LC50 values were determined for single 15-minute exposures. Both fire extinguisher compounds, currently used by the USAF for aircraft fires, were pyrolyzed at 800C in a hydrogen-oxygen flame. The pyrolysis products of each compound were examined and the principle constituents were identified and quantitated. The determined LC50 value of 2300 ppm for pyrolyzed CBrF3 produced a hydrogen fluoride concentration of 2480 ppm consistent with the reported LC50 value for a single 15-minute exposure to this gas. Monobromomonochloromethane pyrolysis products were found to have a LC50 of 465 ppm (as CH2ClBr) under the experimental parameters tested. The toxic response producing this LC50 value appeared to result from a mixture of hydrogen chloride, hydrogen bromide, and bromine gases. (Author)