Acute combined effects of HCN and CO, with the use of combustion products from PAN (polyacrylonitrile)--gauze mistures.

The combustion product from gauze-PAN (Polyacrylonitrile) micture was used as a material for the evaluation of the combined effects of CO and HCN. Rats and mice were exposed for 30 min. to the combustion products. In mice experiments, the time at which animals turned laterally and were killed, was measured. In experiments with rats, blood COHb and cyanide determinations were made, in addition to the observation of the behavior. Exposure room gas concentrations (O2, CO2, CO, HCN) were determined and temperature in the combustion room was measured during heating. Preliminary experiments with PAN, ranging from 2g to 10g, on mice showed that HCN is responsible for the toxicity of the combustion products from this fiber. In mixture experiments all animals died during exposure. In experiments with mice (8g of total weight of mixed sample), animals in groups with larger proportion of PAN turned over and died earlier and this was explained by higher HCN concentration. In rats experiments (10g), this held true for severe impairment, however, as to the death time, this was not the case. There was a long interval between severe impairment and death in groups with larger proportion of PAN. The larger amount of HCN was produced as temperature rises. A linear relation between COHb concentration and CT (concentration-time) product was shown. There was not a linear relation between blood COHb and cyanide levels. Judging from the blood analyses data, it seemed probable that there is neither an additive nor a synergistic action between CO and HCN with respect to lethal effects.