Environmental Health Insights into the 2010 Deepwater Horizon (BP) Oil Blowout

The Deepwater Horizon semi-submersible Mobile Offshore Drilling Unit (MODU), leased to BP (previously British Petroleum, now simply “BP”, with the previously-used promotional tagline of “beyond petroleum”) suffered an explosive “blowout” on April 20, 2010 which resulted in what is now the largest offshore oil spill in United States (U.S.) history, and currently estimated to be at least the second or perhaps third largest oil spill in global history. At the time of writing of this editorial (July 30, 2010), official estimates by the U.S. Department of the Interior (U.S. Geological Survey) indicated that 12,000–19,000 barrels (500–800,000 gallons at 42 U.S. gallons per barrel or 2–3 million liters) of oil were leaking per day for 87 days, for a current total estimate of 44–70 million gallons (167–265 million liters) spilled prior to placement of the current “secure” cap on July 15 (http:// www.doi.gov/news/pressreleases/Flow-Rate-Group-Provides-Preliminary-Best-Estimate-Of-Oil-Flowing-fromBP-Oil-Well.cfm). However, some “unofficial” estimates are much larger, up do 100,000 barrels (4 million gallons or 15 million liters) leaking per day for a total release to date of up to 348 million gallons (1.32 billion liters) prior to July 15. While a significant amount of the oil was captured and recovered (up to 25,000 barrels per day at one point), this is higher than the lower initial estimates of the total daily spill amount, and may have represented less than 25% of the total daily spill amount. Efforts to drill relief wells continue, but unknown amounts of oil continue to leak from the cap and the surrounding seabed due to the tremendous pressures involved (estimated at 11–12,000 pounds per square inch or psi at the wellhead). To place this in perspective, the amount of oil released was roughly equivalent to the total amount of the 1989 Exxon-Valdez oil spill occurring every 3–64 days (based upon the largest to smallest Deepwater Horizon spill estimates, respectively). The largest known environmental oil release in global history, the intentional opening of valves on several oil tankers at the Sea Island oil terminal by Iraqi forces to slow the invasion of U.S. troops in 1991, released an estimated 520 million gallons (1.97 billion liters) into the Persian Gulf. The second largest release was another Gulf of Mexico (Camphece) exploratory well blowout in 1979, which released