Oil spills—liquid petroleum hydrocarbon releases into the environment—accidental, intentional, or resulting from everyday human activity—are all too common and vary in size and duration. Their causes and sources also vary. They are distinguished from natural seeps of oil, such as those that regularly occur in the Gulf of Mexico.
Sources of Spills
Oil undergoes many processes (taking on new characteristics as refined products) and travels many miles in its journey from beneath the earth to the consumer. At any point, it is subject to possible explosion and fire or leakage due to faulty production processes, collisions while in transport, or intentional sabotage.
Production process sites: drilling sites and refineries.
Storage sites: underground tanks, above-ground tanks.
Transport sites/vehicles: roads and railroads. Tankers, barges, vessels, and pipelines.
Most of the largest oil spills in the world have arisen from tanker accidents, although such spills are less frequent than spills caused by pipeline breaks. According to a 2002 US Department of the Interior Minerals Management Service report, tankers and barges were responsible for 45 percent of the spilled oil in United States waters between 1971 and 2000, while pipelines (especially onshore) accounted for only 16 percent. In that same period, offshore (Outer Continental Shelf) production facilities and pipelines accounted for only 2 percent of the volume of oil spilled in United States waters. Nevertheless, the Gulf of Mexico far exceeds other world waters in number of vessel spills and is considered a hot spot for such spills.
Mega-spills of crude oil into the marine environment
There have been numerous oil spills throughout the years in various regions of the world; some of the largest spills, as well as those in U.S. waters, are highlighted in this section. The list of significant spills is lengthy, and the list of the largest spills—those of over 100,000 tons (30 million US gallons)—is similarly long. (A ton of crude oil is approximately 308 US gallons, 7.33 barrels. One barrel of oil is equivalent to 42 US gallons.) Individual oil spills are summarized at Various Oil Spills. The Deepwater Horizon/BP Macondo Well 2010 Gulf of Mexico incident is covered in the Deepwater Horizon Oil Spill section. Below are links to various web sites that offer a wealth of information about oil spills as well as a reference library of books with links to additional information about them. A separate page includes publications about the Deepwater Horizon oil spill.
Part of the history of oil spills includes the clean-up efforts (remediation), both during and after the incident. Another part of the history includes the research and monitoring, both long-term and short-term following the incident. Although this follow-up generally has involved only the natural environment, increasingly it has and should include monitoring of human impacts. And yet another part of the history of oil spills includes the legal/political fallout that may result in compensation for those individuals or entities harmed physically or economically. New laws and regulations sometimes arise to address safety issues and practices as well as liability placement.
Monitoring the environmental impacts of an oil spill should be a long-term proposition; it is critical to our understanding of the full range of effects, and it helps with understanding how the next oil spill might be mitigated. Yet funding typically evaporates with the winds of the next publicized crisis or the complacency that arises from drum beats of "all is back to normal." But environmental monitoring requires a long-term approach and is not as simple as waiting for things to apparently return to the conditions prior to the incident since ecosystems are dynamic and ever-changing. Comparing the change in oiled and unoiled sites is one technique to better assess changes wrought by an oil spill disturbance, for instance. Another is to compare baseline data for a site taken in undisturbed conditions with data after a disturbance. Then, perhaps, a determination of recovery or permanent alteration (regime shift) can be made.
Oil Spills in History
A description of oil spills (accidental discharges) and their sources. Global Marine Oil Pollution Information Gateway
10 Famous Spills, Incident News, Office of Response and Restoration, National Oceanic and Atmospheric Administration
Oil Spill Case Histories, 1967-1991: Summaries of Significant U.S. and International Spills (NOAA/Hazardous Materials Response and Assessment Division, 1992)
Incident News (Office of Response and Restoration, NOAA's National Ocean Service). This site has news, photos, and other information about selected oil spills (and other incidents) where NOAA's Office of Response and Restoration (OR&R) provided scientific support for the incident response. It contains information on thousands of historical incidents spanning 30 years of OR&R spill response. For direct links to historical information and photos on various oil spills.
Incidents Gallery (Office of Response and Restoration, NOAA). Over 1000 photos of various oil spills, including high resolution downloadables.
Oil spills and their data (Centre of Documentation, Research and Experimentation on Accidental Water Pollution)
Tanker Oil Spill Statistics (International Tanker Owners Pollution Federation Ltd)
Oil Rig Disasters (the deadliest, most expensive, blowouts, collapse, sunk rigs, hurricanes, rig list, links)
Pictures of some of the worst oil spills: Sick Slicks: Counting Down the 13 worst Oil Spills
Visualizing Oil Spills, part 1 (oil spill data in visual form, © Christopher Cannon, 2011, with permission)
Visualizing Oil Spills, part 2 (oil spill data in visual form, © Christopher Cannon, 2011, with permission)
Audio interview about what it takes to stop an oil blowout by Stig Christiansen is the CEO of ADD Energy, a Norwegian well-blowout and disaster prevention company - they've assisted in 60 blowouts worldwide including the Gulf of Mexico spill in 2010 and the Montara platform in the Timor Sea.
Oil and oil spills: the Gulf of Mexico — A special edition of Marine Science Review (SeaWeb), dated May 2010, that assembles relevant literature from the three decades preceding the 2010 BP Gulf oil spill, which provide insights not only to the impact of oil on the marine and coastal environment in the Gulf of Mexico, but highlights experiences, issues, and research from similar oil spills in other regions of the world.
Oil Industry History
A History of the Oil Industry (with special emphasis on California and the San Joaquin Valley)
Information about the oil and gas industry, by the industry: types of energy, extraction methods, economic implications, regulations, etc. (Energy Tomorrow.org)
History of Offshore Oil and Gas in the U.S. by National Commission on the BP Deepwater Horizon Oil Spill and Offshore Drilling
Scenes from the Early Days of the U.S. Oil Industry (photos -- The Huffington Post)
National Geographic Magazine: A Geography of Offshore Oil: a map of the Gulf of Mexico with detailed visuals of oil exploration and drilling in the region and relevant numbers