The primary objective of this program was to determine the toxic fume and fire hazard of materials used in the construction of mine stoppings and in the sealing and reinforcing of mine ribs and roofs. The materials investigated were silicone, phenolic, and isocyanate- based rigid foams, as well as epoxy and acrylate mine sealants. Of the rigid foams tests, the x-156 urethane foam presented the greatest toxic hazard based on toxic load values, and hydrogen chloride was the main toxic species evolved by this foam. In none of the isocyanate-based compositions was hydrogen cyanide the major component, but its contribution increased with temperature. Of the two mine sealants tested, the latex acrylic coating presented the greater toxic hazard; acetic acid was the main toxic species evolved.