A carcinogenic bioassay of certain roofing materials.

The carcinogenic potentials of certain present day roofing materials and dust produced during the removal of an old coal tar pitch roof were evaluated using a mouse skin bioassay. Traditional coal tar pitch and dust from removal of an old roof were significantly more carcinogenic than coal derived roofing bitumen, but all were strongly carcinogenic. The benzo(a)pyrene concentration of these materials ranged from 0.064 to 0.08%, but each was significantly more carcinogenic than 0.1% benzo(a)pyrene alone. No tumors were produced by the application of petroleum derived roofing asphalt.