Polyurethane foam will burn if exposed to an open flame or other sufficient heat source. Do not expose polyurethane foam to open flames or any other direct or indirect high temperatures ignition source such as burning operations, welding, burning cigarettes, space heaters, or naked lights. Once ignited, polyurethane foam will burn rapidly releasing great heat and consuming oxygen at a high rate. In an enclosed space, the resulting deficiency of oxygen will present a danger of suffocation to the occupants. Hazardous gases released by the burning foam can be incapacitating or fatal to human beings if inhaled in sufficient quantities. Once ignited, polyurethane foam is difficult to extinguish. Foam fires that appear to be extinguished may smolder and re-ignite. Always have fire officials determine whether a fire has been extinguished. Bulk purchaser or users of polyurethane foam should take appropriate precautions to ensure that it is properly handled and stored and, depending upon the intended use of the foam, that suitable warnings are provided to the ultimate customers.