For each trial, the cumulative mortality was high- est for the 0 ppm dose. No clear pattern or significant difference was observed between the doses. In trial 4, 150 ppm dose had the highest mortality suggesting a possible toxic effect. The 150 ppm dose in trial 4 had the highest average formaldehyde concentration of all the trials. The first two treatments in trial 4 had formaldehyde levels that corresponded more closely to a 170 ppm dose rather than
150 ppm