[Further studies of the toxicity of volatile thermal degradation products of conveyor belts].

Toxic effects of the thermal degradation products of polivinyl chloride and rubber conveyor belts, preliminarily filtered through modified mining gas-mask container were studied in guinea pigs. The smoke concentration was approximate to the one found in mines near the fire during minimal ventilation (0.15 m/sec.) Within 60 min. exposure the test products showed slight irritative effects and caused a moderate lung injury and small degenerative lesions in the liver and kidney. All these changes were rather reversible and did not involve any risk to the animals' lives. The modified container reduced the toxicity of the test substances much more than did the hitherto used mining gas-mask container.