Industrial fuel oil is a fraction obtained from petroleum distillation; the term fuel oil is also used in a stricter sense to refer only to the heaviest commercial fuel that can be obtained from crude oil.

Low suphur content also gives it advantage from the point of envornmental pollution since it produces lesser quantity of sulphur dioxide. It is considered as environmental friendly due to low sulphur percentage. The main advantage in the use of industrial fuel oil lies is its low sulphur content.

Industrial fuel oil is yellow in color. It is used in engines with an rpm less than 750, such as boilers and furnaces.