関連ワード:  is gasoline flammable or combustible    is gas flammable or combustible    is petrol flammable or combustible    is fuel flammable or combustible    is gasoline a flammable or combustible liquid    is cs gas flammable or combustible    is natural gas flammable or combustible    is sewer gas flammable or combustible    is oxygen gas flammable or combustible    is hydrogen gas flammable or combustible