Editing Petroleum (section)

=== Oil spills ===
{{Further|Oil spill|List of oil spills}}
{{multiple image
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| image1 = Oil-spill.jpg
| caption1 = Kelp after an oil spill.
| image2 = Oil Slick in the Timor Sea September-2009.jpg
| caption2 = Oil slick from the [[Montara oil spill]] in the Timor Sea, September 2009.
| image3 = PrestigeVolunteersInGaliciaCoast.jpg
| caption3 = Volunteers cleaning up the aftermath of the [[Prestige oil spill]].
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Crude oil and refined fuel [[Oil spill|spills]] from [[tanker ship]] accidents have damaged natural [[ecosystem]]s and human livelihoods in [[Alaska]], the [[Gulf of Mexico]], the [[Galápagos Islands]], France and many [[List of oil spills|other places]].

The quantity of oil spilled during accidents has ranged from a few hundred tons to several hundred thousand tons (e.g., [[Deepwater Horizon oil spill]], [[SS Atlantic Empress]], [[Amoco Cadiz]]). Smaller spills have already proven to have a great impact on ecosystems, such as the [[Exxon Valdez oil spill|''Exxon Valdez'' oil spill]].

Oil spills at sea are generally much more damaging than those on land, since they can spread for hundreds of nautical miles in a thin [[oil slick]] which can cover beaches with a thin coating of oil. This can kill sea birds, mammals, shellfish, and other organisms it coats. Oil spills on land are more readily containable if a makeshift earth dam can be rapidly [[bulldozed]] around the spill site before most of the oil escapes, and land animals can avoid the oil more easily.

Control of oil spills is difficult, requires ad hoc methods, and often a large amount of manpower. The dropping of bombs and incendiary devices from aircraft on the {{SS|Torrey Canyon}} wreck produced poor results;<ref>[[Torrey Canyon oil spill|Torrey Canyon bombing by the Navy and RAF]]</ref> modern techniques would include pumping the oil from the wreck, like in the [[Prestige oil spill|''Prestige'' oil spill]] or the [[MV Erika|''Erika'']] oil spill.<ref>{{Cite web |title=Pumping of the Erika cargo |url=http://www.total.com/en/group/news/special_report_erika/erika_measures_total/erika_pumping_cargo_11379.htm |url-status=live |archive-url=https://web.archive.org/web/20081119225756/http://www.total.com/en/group/news/special_report_erika/erika_measures_total/erika_pumping_cargo_11379.htm |archive-date=November 19, 2008 |access-date=August 29, 2010 |publisher=Total.com}}</ref>

Though crude oil is predominantly composed of various hydrocarbons, certain nitrogen heterocyclic compounds, such as [[pyridine]], [[picoline]], and [[quinoline]] are reported as contaminants associated with crude oil, as well as facilities processing oil shale or coal, and have also been found at legacy [[creosote|wood treatment]] sites. These compounds have a very high water solubility, and thus tend to dissolve and move with water. Certain naturally occurring bacteria, such as ''[[Micrococcus]]'', ''[[Arthrobacter]]'', and ''[[Rhodococcus]]'' have been shown to degrade these contaminants.<ref>{{Cite journal |last1=Sims |first1=Gerald K. |last2=O'Loughlin |first2=Edward J. |last3=Crawford |first3=Ronald L. |year=1989 |title=Degradation of pyridines in the environment |journal=Critical Reviews in Environmental Control |volume=19 |issue=4 |pages=309–340 |doi=10.1080/10643388909388372|bibcode=1989CRvEC..19..309S }}</ref>

Because petroleum is a naturally occurring substance, its presence in the environment does not need to be the result of human causes such as accidents and routine activities ([[seismic]] exploration, [[Boring (earth)|drilling]], extraction, refining and combustion). Phenomena such as [[seeps]]<ref>{{Cite web |title=Seeps Home Page |url=http://seeps.wr.usgs.gov/ |archive-url=https://web.archive.org/web/20080820012319/http://seeps.wr.usgs.gov/ |archive-date=August 20, 2008 |access-date=May 17, 2010}} Natural Oil and Gas Seeps in California</ref> and [[tar pit]]s are examples of areas that petroleum affects without man's involvement.