Gasoline is a transparent yellowish or greenish, volatile, toxic, and highly flammable liquid that consists of a mixture of about 150 hydrocarbon compounds (including toluene, methyl tert-butyl ether, trimethylbenzene, benzene and naphthalene). It is obtained from the refining of crude oil, and is enhanced with a variety of additives, including lubricants, anti-rust chemicals and anti-icing agents. It is used mostly as a fuel in spark-ignited internal combustion engines.
Gasoline is produced and consumed on a massive scale. It is the largest use of crude oil, at about 40 to 50 percent, and followed by diesel fuel at about 30 percent. The U.S. is by far the largest producer and consumer of gasoline, consuming more than twice that of China, the second largest consumer.
Gasoline can enter the environment in various ways and contaminate the soil, surface water, groundwater and air. This includes as a liquid from spills or improper disposal and as a vapor from leaks occurring during its production, handling, transport and delivery. Leaks frequently occur from underground storage tanks and pipelines, and vapor release commonly occurs when large tanker trucks are filled and emptied and when automobile fuel tanks are filled.
In addition to releasing various carcinogens, the burning of gasoline is also one of the main causes of climate change. This is clear from the facts that it is the largest product refined from crude oil and that crude oil products as a whole account for about a third of carbon dioxide emissions.
As the world will likely be approaching 'peak oil' in the next two or three decades, it will also be approaching 'peak gasoline.'