Fuel Oil is a fraction obtained from petroleum distillation, also known as marine fuel or furnace oil. Fuel Oil is also used in a stricter sense to refer to the heaviest commercial fuel that can only be obtained from crude oil, which is heavier than gasoline and naphtha. While heavier petroleum products like diesel fuel and lube oil are much less volatile and distilled slower, Bunker Oil is literally the bottom of the barrel.
IFO has many uses; It heats homes and businesses and is the fuel for trucks and ships It is often used as backup fuel for power plants or as the main fuel for small electric generators in case the natural gas supply is interrupted. Now IFO is less useful because it needs to be heated with a special heating system before use. It is a high amount of pollutant. It contains sulfur, which forms sulfur dioxide, especially during combustion. However, its unwanted properties make it very cheap. In fact, it is the cheapest liquid fuel available.