is a relatively colorless light distillate, heavier than gasoline (see distillation). It is used for lighting and heating, and as a fuel for some internal combustion engines. The two grades of kerosene, as defined in ASTM-D-3699, are: Grade 1-K, a low-sulfur kerosene with a maximum sulfur content of 0.04 mass percent, intended for use in flueless burner appliances, and Grade 2-K, with a maximum sulfur content of 0.30 mass percent, intended for use in flue-connected appliances.