“Depending on the type and location of the flashings, roofing tar or silicone or butyl rubber sealants can be used to seal small cracks and gaps.”

“However, in Philadelphia, refineries had reformulated gasoline to include increased concentrations of methyl tertiary butyl ether.”

“These may contain solvents such as toluene, isopropryl alcohol, ethyl and butyl acetates, acetone and other ketones.”