Fire toxicity toxicants effect, species

OH species-conflicting reports LD50 subcutaneous (mice) 15 mg/kg, intraperitoneal (rats) 17.5 mg/kg toxic effects—CNS depression and convulsion explosive mixture with air fire-extinguishing agent alcohol foam or water spray... 

All fire smoke is toxic. In the past two decades, a sizable research effort has resulted in the development of over twenty methods to measure the toxic potency of those fire smokes (6). Some methods have been based on determinations of specific chemical species alone. Values for the effect (e.g., lethality) of these chemicals on humans are obtained from (a) extrapolation from preexisting, lower concentration human exposure data or from (b) interpretation of autopsy data from accident and suicide victims. The uncertainty in these methods is large since ... 

The general approach in generating toxic potency data from chemical analysis is to assume additive behavior of individual toxicants, and to express the concentration of each toxicant as its fraction of the lethal concentration for 50% of the population for a 30 min exposure (LC50). Thus an fractional effective dose (FED) equal to one indicates that the sum of concentrations of individual species will be lethal to 50% of the population over a 30 min exposure. Two equations have been developed for the estimation of the FED for lethality from the chemical composition of the environment in the physical fire model. Each begins with the precept that the fractional lethal doses of most gases are additive, as developed by Tsuchiya and Sumi.32... 

Another approach is to attempt to chemically modify the toxicants to yield nontoxic products which are returned to their active state by digestive or metabolic processes. The pesticide trichlotfon, which is toxic to fire ants, is not effective as an agent for control of the species due to its rapid action. Polymeric insecticides of the ester of trichlorfon with PAA have been prepared with hydrolytically unstable covalent linkages [225]. The preparation of polymeric esters of trichlorfon with spacer groups between the insecticide and the polymer backbone 2 have been prepared to eliminate the limited toxicity of the polymeric insecticide 1, which is a reflection of the limited loading and slow hydrolysis of the insecticide due to the steric hindrance of the polymer backbone (Scheme 3.18). 

Fire retardant additives are added to resins by the suppliers to improve their fire performance. In selecting such resins, care must be taken that the additives in turn do not emit toxic species or have other undesirable effects. 

Testing involves identifying the nature, concentration and injurious effects of the major gaseous species. The rate of evolution of the toxic species will in turn depend upon the type of fire. 

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