Gasoline in a mason jar
A typical gasoline container holds 1.03 U.S. gallons (3.9 L).

Gasoline (/ˈɡæsəln/) or petrol (/ˈpɛtrəl/) (see the etymology for naming differences) is a transparent, petroleum-derived flammable liquid that is used primarily as a fuel in most spark-ignited internal combustion engines. It consists mostly of organic compounds obtained by the fractional distillation of petroleum, enhanced with a variety of additives. On average, a 160-liter (42-U.S.-gallon) barrel of crude oil can yield up to about 72 liters (19 U.S. gallons) of gasoline after processing in an oil refinery, depending on the crude oil assay and on what other refined products are also extracted.[1] The characteristic of a particular gasoline blend to resist igniting too early (which causes knocking and reduces efficiency in reciprocating engines) is measured by its octane rating, which is produced in several grades. Tetraethyl lead and other lead compounds, once widely used to increase octane rating, are no longer used in most areas (they are still used in aviation[2] and auto-racing[3]). Other chemicals are frequently added to gasoline to improve chemical stability and performance characteristics, control corrosiveness, and provide fuel system cleaning. Gasoline may contain oxygen-containing chemicals such as ethanol, MTBE, or ETBE to improve combustion.

Gasoline can enter the environment uncombusted, both as liquid and as vapor, from leakage and handling during production, transport, and delivery (e.g., from storage tanks, from spills, etc.). As an example of efforts to control such leakage, many underground storage tanks are required to have extensive measures in place to detect and prevent such leaks.[4] Gasoline contains benzene and other known carcinogens[5][6][7] and causes over 100 thousand premature deaths every year.[8]

  1. ^ "Gasoline—a petroleum product". U.S Energy Information Administration website. U.S Energy Information Administration. 12 August 2016. Archived from the original on 24 May 2017. Retrieved 15 May 2017.
  2. ^ Kessler, Rebecca (February 2013). "Sunset for Leaded Aviation Gasoline?". Environmental Health Perspectives. 121 (2): a54–a57. doi:10.1289/ehp.121-a54. PMC 3569701. PMID 23380048. Retrieved 30 July 2020.
  3. ^ "Race Fuel 101: Lead and Leaded Racing Fuels". Retrieved 30 July 2020.
  4. ^ "Preventing and Detecting Underground Storage Tank (UST) Releases". United States Environmental Protection Agency. 13 October 2014. Retrieved 14 November 2018.
  5. ^ "Evaluation of the Carcinogenicity of Unleaded Gasoline". Archived from the original on 27 June 2010.
  6. ^ Mehlman, MA (1990). "Dangerous properties of petroleum-refining products: carcinogenicity of motor fuels (gasoline)". Teratogenesis, Carcinogenesis, and Mutagenesis. 10 (5): 399–408. doi:10.1002/tcm.1770100505. PMID 1981951.
  7. ^ Baumbach, JI; Sielemann, S; Xie, Z; Schmidt, H (15 March 2003). "Detection of the gasoline components methyl tert-butyl ether, benzene, toluene, and m-xylene using ion mobility spectrometers with a radioactive and UV ionization source". Analytical Chemistry. 75 (6): 1483–90. doi:10.1021/ac020342i. PMID 12659213.
  8. ^ "The Climate and Health Impacts of Gasoline and Diesel Emissions". Eos. Retrieved 23 February 2021.