Natural gas coming out of the well is mostly methane and ethane. There may be propane and butane given off in lesser amounts. These chemicals do not generally pose a health problems. The most harmful component in natural gas is hydrogen sulfide. It appears that the Macondo well is not producing hydrogen sulfide, or at least not at levels considered harmful to health.
However, as indicated on the link, the EPA is concerned about gases that can be given off as a result of the evaporation of the oil spill and the dispersants that have been added to the oil spill. These compounds, generally grouped as Volatile Organic Compounds (VOC), include benzene, and can be harmful in small quantities.
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The cause of the oil spill was that gases in one pipe were building up and then it eventually exploded.
Don't Spill the Eggs - 2011 was released on: USA: 27 May 2011
The Spill Canvas' 'Our Song' - 2010 was released on: USA: 10 August 2010
Don't Spill the Beans - 1965 was released on: USA: 26 May 1965
Saved from the Spill - 2010 TV was released on: USA: 5 October 2010
The BP oil spill released large amounts of methane, a potent greenhouse gas, into the atmosphere. Additionally, the clean-up efforts required burning large quantities of oil, releasing even more greenhouse gases. The environmental damage caused by the spill also impacts ecosystems, which play a crucial role in regulating the Earth's climate.
After the Spill The Last Catch - 2010 TV was released on: USA: 28 September 2010
Rescue Heroes - 2000 Arctic Spill was released on: USA: 3 June 2001
Natural gas is being released into the atmosphere. It is a clear danger to the rigs operating in the area, as the oil slick and gases can ignite. Fortunately, the oil is apparently sweet, so the H2S level is sufficiently low. All rigs have gas monitors to detect the presence of H2S. Gas disperses rapidly, but the EPA is sampling the air, and checking for contaminants. No health advisories have been issued. Natural gas is a greenhouse gas, so there is also a longer term impact on the environment for this spill.
Endurance - 2002 Fill and Spill 5-7 was released on: USA: 20 January 2007
The Final Report - 2006 Exxon Valdez Spill was released on: USA: 24 March 2008
Changing Seas - 2009 After the Spill 3-4 was released on: USA: 28 June 2011