In a fire situation, Polyurethane is a death trap. Poisonous gases like Hydrogen Cyanide (Adler/Mackwitz: Eco tricks and Swindles, page 274).
Isocyanates are part of a particularly dangerous group of chemicals. Even small concentrations of fumes or dust (produced by normal wear and tear of these materials) in a room can cause serious health damage.
Holz100 Canada Inc.