Acute Inhalation Toxicity in Rats Exposed to Thermal Degradation Products of a New Chlorinated Fluid for Electrical Transformers

The dielectric fluid LIHT-TI, a 60:40 mixture of tetrachlorobenzyl toluene and trichlorobenzene, is used in electrical transformers. The acute in halation toxicity of its thermal decomposition products was assessed in rats. Askarel-T1, a 60:40 mixture of 6 chlorobiphenyl and trichlorobenzene, and a paraffinic mineral oil were also tested for comparison purposes. Animals (6 per group) were exposed for one hour to atmospheres resulting from heating the fluids to 500 °C and 700 °C. They were followed for 14 days after exposure. No mortality occurred in the LIHT-T1 group. Only slight and transient respiratory discomfort was noticed during exposure. The effects on growth were virtually nil, expected for some slight initial retardation during the first two days post-exposure. The effects induced by Askarel-T1 were similar if a little more pronounced. Initial retardation of growth lasted longer, respiratory im pairment was more important, and small lesions consisting of hemorrhagic areas were observed. The difference would not seem to be attributable to a greater degree of thermal degradation, since both Askarel-T1 and LIHT-T1 were only moderately decomposed.