Toxicity of the Atmosphere in an Upstairs Room Caused by Inflow of Fire Effluent Gases Rising from a Burn Room

Fire experiments were repeatedly conducted in a fire-resistant 2-story house to investigate the toxicity of atmosphere in its second floor room, using one of the first floor rooms as a burn room, which was fully equipped with construction materials and house contents. In each fire experiment only the size of the opening of the doorway to the second floor room was varied. The tox icity was found to become sufficiently high to cause death to rabbits exposed to cooled gases taken from any location in the second floor room, even when the doorway to the second floor room was almost completely closed. Major toxicants were limited to CO and HCN, as in our earlier study [1]. Although the blood cyanide level was always below 2.0 μg/mL, HCN must have had an important role in causing death to the rabbits, because the COHb level mostly remained below 50%.