Fuel oil is a general term for a number of burnable liquids made from crude oil. No. 4 is a diesel fuel for boats. All fuel oil mixtures have similar chemical and physical properties. Fuel oils are used to run many types of engines, lamps and heaters. Sometimes small amounts of fuel oil are stored in portable containers for use in space heaters, to clean metal parts, or used in camp stoves or lanterns.
Most fuel oil entering the environment comes from spills or leaking storage tanks.
When spilled on soil, some components of fuel oil attach to soil. Furthermore, fuel spilled on water or soil, evaporates into the air. Fuel oil can also contaminate soil sediments and private drinking water supplies. Other situations include using kerosene heaters, or using kerosene to clean machinery or paint brushes. If water supplies are contaminated, people can inhale the vapors as they bathe, do laundry or use the water for other household purposes.