Benzene, also known as benzol, is an organic chemical compound with the formula C6H6. It is sometimes abbreviated PhH. Benzene is a colorless and flammable liquid with a sweet smell and a relatively high melting point.

It is an aromatic hydrocarbon produced by the burning of natural products. It is used in the manufacture of numerous products and it is a human carcinogen.

Benzene is a clear, colorless liquid at room temperature and it readily evaporates in to the air. Its vapor is heavier than air so it will stay close to the ground. Small traces of benzene can be observed whenever carbon-rich materials undergo combustion.

Until World War II, most benzene production came as a byproduct of smelting steel. As demand increased in the 1950s because of its heightened importance as an industrial solvent, benzene began to be created using petroleum. Benzene production has diminished over the years due to its carcinogenic effects.

Benzene was first used in the 19th and early 10th century as an aftershave lotion and for douches because of its pleasant smell. It was also used around this time as an industrial solvent to degrease Metals, to decaffeinate coffee, and later was used as an additive to petrol because it increases the octane rating and reduces knocking in the engine. It was replaced by tetra-ethyl lead but has benzene has recently began to be used again as Lead use is being retracted. The use is very limited due to concerns over its toxicity and ability to leach into the groundwater (It is around 2% of gasoline in the US but can be up to 5% in other countries).

Benzene use today is immense, measured in the billions of pounds making it one o the top 20 most widely used Chemicals List. It is mainly used in the production of other chemicals such as dyes, drugs, Pesticides, and products such as rubber, nylon, and glues to name only a few.