Gasoline, also known as petrol, is a transparent, yellowish, and flammable liquid that is used as a fuel for spark-ignited, internal combustion engines. It is a petroleum product that is mainly made from crude oil and other petroleum liquids. Gasoline is a complex mixture of hundreds of different hydrocarbons, most of which are saturated and contain 4 to 12 carbon atoms per molecule. The exact chemical composition of gasoline is undefined, and it is produced to meet a host of engine performance specifications, which means that many different compositions are possible. Gasoline is chemically enhanced with gasoline additives to improve its performance and stability.
Gasoline is sold in three main grades at retail gasoline refueling stations: regular, midgrade, and premium. The formulation of gasoline may differ depending on the location where it is sold or the season of the year. Federal and state air pollution control programs that aim to reduce carbon monoxide, smog, and air toxins require oxygenated, reformulated, and low-volatility gasoline.
Gasoline is a highly flammable liquid that can form explosive mixtures in air. It is also a toxic substance that can cause contamination of soil, groundwater, surface water, and air if spilled, leaked, or improperly disposed of. Gasoline can be released into the air when large tanker trucks are filled and emptied and when you fill your car at the service station. The most common exposure to gasoline occurs by breathing its vapors.
