Refined petroleum products are derived from crude oils through processes such as catalytic cracking and fractional distillation. These products have physical and chemical characteristics that differ according to the type of crude oil and subsequent refining processes. Several examples of refined petroleum products and their properties include:

Gasoline, a lightweight material that flows easily, spreads quickly, and may evaporate completely in a few hours under temperate conditions. It poses a risk of fire and explosion because of its high volatility and flammability, and is more toxic than crude oil. Gasoline is amenable to biodegradation, but the use of dispersants is not appropriate unless the vapors pose a significant human health or safety hazard.

Kerosene, a lightweight material that flows easily, spreads rapidly, and evaporates quickly. Kerosene is easily dispersed, but is also relatively persistent in the environment.

No. 2 Fuel Oil, a lightweight material that flows easily, spreads quickly, and is easily dispersed. This fuel oil is neither volatile nor likely to form emulsions, and is relatively non-persistent in the environment.

No. 4 Fuel Oil, a medium-weight material that flows easily, and is easily dispersed if treated promptly. This fuel oil has a low volatility and moderate flash point, and is fairly persistent in the environment.

No. 5 Fuel Oil (Bunker B), a medium-weight to heavyweight material with a low volatility and moderate flash point. Preheating may be necessary in cold climates, and this fuel oil is difficult, if not impossible, to disperse.

No. 6 Fuel Oil (Bunker C), a heavyweight material that is difficult to pump and requires preheating for use. This fuel oil may be heavier than water, is not likely to dissolve, is difficult or impossible to disperse, and is likely to form tar balls, lumps, and emulsions. It has a low volatility and moderate flash point.

Lubricating Oil, a medium-weight material that flows easily and is easily dispersed if treated promptly. This oil has a low volatility and moderate flash point, but is fairly persistent in the environment.