In the days leading up to the 6th month anniversary of the BP deepwater drilling disaster, GRN is highlighting nine previous oil disasters, to give historic context to what the Gulf of Mexico is experiencing, and will experience for years to come.Exxon Valdez, 1989 The Exxon Valdez oil spill is one of the worst spills in the U.S., and is one of the most analyzed environmental disasters within the past 50 years. The spill began when the tanker unexpectedly hit an undersea reef on March 24, 1989 in Prince William Sound, Alaska. The vessel had been carrying 53 million gallons of Prudhoe Bay crude and lost 10.9 gallons in the spill.The clean up of the oil spill was long and involved, with many learning experiences and tests done along the way. Logistical problems such as providing fuel, response equipment, waste management and other resources were some of the largest challenges faced by the response team. At the time of the initial spill, the Alyeska spill response barge was out of service. The barge arrived shortly after the incident occurred, but was quickly overwhelmed by the magnitude of the spill. On March 25 Exxon assumed full responsibility for the spill and the following clean up.The clean up involved many different methods of containing and collecting oil. Due to a shortage in booms, the federal, state and local agencies collaborated in initiating shoreline protection priorities, with the fish hatcheries and salmon streams being the top priority. The response team had much success with the booms deployed throughout the area. The deflection of oil from the fish hatcheries and streams was a success. A 3M fire boom was used to collect 15,000 to 30,000 of floating oil and contain it for burning. According to a report by NOAA, the oil burned for 75 minutes and the efficiency of the burn was 98% or better. Once the oil was contained by the booms, skimmers, hopper dredges and vacuum equipment were all employed for collecting and transferring the oil. The vacuum trucks on barges and air conveyors were the most useful when used with open-ended suction hoses. The high-capacity skimmer offloading pumps, especially the grain pumps, were the most useful in transferring the viscous oil.Sorbents and dispersants were also involved in the clean up response efforts. Although sorbents were highly labor intensive and generated additional waste, they were useful when mechanical means were impractical. Dispersants were used on both the oil slick in the ocean, as well as along the shore. Dispersant tests were conducted on March 25 and 26 and Exxon was given permission to utilize the dispersants on the oil slick on March 26. Only some of the dispersants were actually used due to a storm occurring that night and turning the oil into mousse, rendering the dispersants useless. On shore, Corexit 7664 paired with a warm wash was used on Ingot Island. The dispersant and wash caused no noticeable change in the physical state of the oil or the oil cover. The wash was more damaging to the environment than expected, especially the intertidal epibenthic macrobiota. The dispersant BP1100X was applied to a small test area on Knight Island. Dispersant use was ceased due to intertidal biota having lower counts after the dispersant was distributed. It took seven days for the communities to return to pre-dispersant levels. In an effort to move away from dispersants, phosphorous and nitrogen were added to the shorelines in an attempt to enhance bioremediation. The tests proved that oil was degraded in the areas, although the tests did not prove whether the degradation was due to enhanced microbial activity. Since the spill in 1989, research has been conducted and policies created that will help with future spills. Research has proven that green algae and certain types of worms were able to recover and return to the oiled areas within a year of the spill. Rockweed and barnacles returned to the are within two to three years. Other animals, such as mollusks, limpets and some snails, are much more sensitive and have still not reached pre-spill status. Clams and mussels were especially damaged by the spill and some are still contaminated. In some particular beach areas, such as Smith Island, oil sill leaches from the ground. Certain beaches that underwent high-pressure, hot water cleaning are still experiencing bare rock with not plant re-growth. In regards to fisheries, no evidence of mass kills of adult open water fish were recorded. In 1990, the Oil Pollution Act established the Oil Spill Recovery Institute (OSRI) in response to the Exxon Valdez disaster. The goals of the OSRI are to identify and develop the best available techniques, equipment and materials for dealing with spills in the Arctic and sub-Arctic marine environments. Also, the OSRI aims to “complement federal and state damage assessment efforts and determine document, assess and understand the long-range effects of Arctic and sub-Arctic oil spills on the natural resources of Prince William Sound, and the environment, the economy and the lifestyle and well-being of the people who are dependent on those resources.” Above Photos: NOAA Incident News, Exxon Valdez oil spill cleanup and U.S. Fish and Wildlife, Spill response and restoration
