Gulf Coast Oil Spill

May 6, 2010 -- Nearly two weeks after an oil rig explosion off the coast of Louisiana, efforts are still under way to stop massive amounts of oil spilling out from an undersea well. Moreover, the vast oil slick produced from the leak continues to creep slowly toward towns and habitats on shore. To minimize the impact of the oil spill, crews are unloading chemicals known as dispersants into Gulf waters. A 2005 report from the National Research Council, Understanding Oil Spill Dispersants: Efficacy and Effects, examined the effectiveness of these chemicals that remove oil from the water's surface by breaking it down into tiny droplets that physically mix into the water column.

Although oil spill dispersants do not actually reduce the amount of oil, they can decrease the potential for a surface slick to contaminate shoreline habitats or come into contact with birds, marine mammals, or other organisms. However, the report emphasizes, using dispersants involves trade-offs between decreasing the risks along shorelines and on the water surface and increasing the potential risks to plant and animal life in the water column and on the seafloor.

Another National Research Council report from 2002, Oil in the Sea III: Inputs, Fates, and Effects, estimates that nearly 85 percent of the 29 million gallons of petroleum that enter North American ocean waters as a result of human activities each year comes from land-based runoff, polluted rivers, airplanes, and small boats and jet skis, while less than 8 percent comes from tanker or pipeline spills. The report also states that effects of a major oil spill are longer lasting than once thought and that even small amounts of petroleum can seriously damage marine life and ecosystems and have long-term adverse consequences.

A recent Transportation Research Board report, Risk of Vessel Accidents and Spills in the Aleutian Islands: Designing a Comprehensive Risk Assessment, presents a framework for conducting a comprehensive risk assessment of the region's shipping -- work that has been recently initiated following the report's recommendations. And a 2003 National Research Council report, The Oil Spill Recovery Institute: Past, Present, and Future Directions, assesses the research program created by Congress in response to the Exxon Valdez spill to support oil-spill related research, education, and technology development projects for dealing with oil spills in Arctic and sub-Arctic marine environments.

Other reports of interest:

• Environmental Performance of Tanker Designs in Collision and Grounding: Method for Comparison (2001)
• Spills of Nonfloating Oils: Risk and Response (1999)
• Oil Spill Risks From Tank Vessel Lightering (1998)
• Tanker Spills: Prevention by Design (1991)

• Disasters Roundtable