Abstract
Halogenated fire extinguishants break down during the process of extin guishing flame and the acute toxicity of the breakdown products of halon 1211 has been investigated. Rats were exposed for 5 minutes to breakdown products generated by the partial extinguishment of a propane flame at concentrations of 350 ppm, 1200 ppm and 2900 ppm total halogen acid gas. Apart from sensory irritation during exposure, there were no significant effects at 350 ppm and 1200 ppm. Exposure to 2900 ppm caused sensory irritation, some ophthalmitis and a transient weight loss. A parallel series of experiments was carried out to determine the concentration of breakdown products when halon 1211 extin guishers were used to put out a variety of small fires. Except where a large solvent fuel load caused such a large fire that the operator had to wear protective clothing to approach the fire, the breakdown products did not exceed 100 ppm. It can be concluded that halon 1211 decomposition products do not add significantly to the hazardous conditions caused by fires in the form of smoke, heat, oxygen depletion and toxic gas production.
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