Case Studies

Exxon Valdez
Website:http://www.valdezalaska.org/history/oilSpill.html
Summary:The oil spill known as the Exxon Valdez, occurring on March 24, 1989, was caused when a tanker who was destined for California from Alaska ran aground on Bligh Reef in the Prince William Sound, Alaska. Many factors contribute into making this the worst spill in US History. Within the first 6 hours of grounding, the Exxon Valdez spilled 10.9 million gallons of unrefined crude oil from eight of its eleven oil tanks. Response vehicles were engaged and the production of containment began using booms, absorption, and dispersants, however, the factor that turned this contained spill into a catastrophic event was the storm on March 26, 1989. This storm caused the oil to turn into mouse and tar balls that were no longer compatible with the dispersants previously used, was uncontainable due to the mass spread, and now contaminated 1,100 miles of Alaskan coastline. The cobblestone/ course-sand shorelines caused the oil to seep into the sub-surface. The total clean up took about a year; however, even today there are samples of shoreline taken, where there is still a sheen of oil in the sub-surface. This oil spill caused the death of much wildlife, as well as the contamination of most. Thus, the Exxon Valdez is remembered by most as the most disastrous spills in the US waters.



Ixtoc 1
Website:http://response.restoration.noaa.gov/book_shelf/26_spilldb.pdf
Summary:The Ixtoc 1 oil spill on June 6, 1979 occurred in Bahia de Campeche, Mexico when the PEMEX oil companies 2 mile deep oil well blew out caused by the loss of drilling mud circulation. The well caught on fire with the oil surfacing, causing it to collapse, which obstructed any chance to control the blowout. Blowout committees worked to close the blowout preventer on the ocean floor, but valves began rupturing so the preventer was reopened. Two relief wells were drilled to relieve pressure from the well that would allow the slow of oil, and the pumping of mud, steel, iron and lead balls into the well reduced the flow to only 10,000 barrels a day. Ultimately, 140 million gallons of oil was spilled and affected 162 miles of US beaches. The well was finally capped and oil stopped leaking on March 23, 1980, almost a year after the initial accident.



BP Deepwater Horizon
Website:http://www.bp.com/extendedsectiongenericarticle.do?categoryId=40&contentId=7061813
Summary:The Deepwater Horizon, a drilling rig in the Gulf of Mexico, blew out and sank on April 22nd, killing 11 people and detached the pipe leading from the well to the surface causing oil to leak. Also, there are three leaks within the well itself, causing as much as 25,000 barrels (1,050,000 gallons) of oil per day leaking into the water. About 20,000 personnel, 900 vessels, and 1.9 million booms were sent to contribute to solving this national problem. There has recently been a dome put over the well that will contain about 85% of the leaking oil. This will hopefully reduce the flow of oil significantly, and the U.S. Coast Guard is potentially going to construct a relief well that can funnel most oil to the surface safely, and eventually pump concrete to permanently seal the leaking well. This spill is estimated to affect about 800 miles of U.S. and Caribbean shoreline. Once the oil hit the shore on April 30th, the Deepwater Horizon spill was said to belittle the Exxon Valdez in terms of environmental damage.