Introduction
The EXXON VALDEZ oil spill in 1989 had many significant and far-reaching effects, both on the shorelines of Prince William Sound, Alaska and subsequently on the entire U.S. structure for combating oil spills. It also led to a number of successful new programs within Exxon and industry aimed at reducing incidents, minimizing spillage of oil worldwide, and improving the capability to respond in the event of a spill. The VALDEZ was the largest marine oil spill in U.S. history. Exxon's response effort is widely acknowledged as the largest peacetime industrial mobilization ever in the U.S. and possibly in the world. Exxon spared no expense in committing resources and personnel to cleanup the shorelines affected by the spill. Noted oil spill experts confirm that the area is essentially recovered, in large part because of efforts made during 1989-91.
The VALDEZ spill is the most studied ever. The cleanup involved application of technology not previously applied to large spills. Many of these applications are now the subject of ongoing international research programs aimed at improving the ability to respond. This paper, written by an Exxon scientist who coordinated several technical studies in support of the cleanup, summarizes many of the learnings and advances to come out of the spill experience, with emphasis on how these many apply to today's spills. This paper discusses only the response and cleanup. Exxon also initiated a number of programs to mitigate impacts on people, communities and wildlife affected by the spill.
Summary of the Spill
On March 24, 1989, the EXXON VALDEZ, a 300 m (987 ft), state-of-the-art tanker carrying 1.25 million barrels (196,000 t) of Alaska North Slope (ANS) crude oil went aground on Bligh Reef in Alaska's Prince William Sound. The grounding opened 8 of the vessel's 11 cargo tanks and 3 of the 5 ballast tanks, releasing about 260,000 barrels (41,000 t) of ANS into the water, almost all of it within the first few hours. The site of the spill was very remote, far from major population centers and only a accessible by boat and aircraft. Consistent with the area oil spill contingency plan, the initial response was carried out by Alyeska Pipeline Service Company (operator of the marine terminal at Valdez) and by the U.S. Coast Guard. Exxon has very limited operations in Alaska. However, company personnel began arriving from its main center of operations in the Gulf Coast of Texas, some 5,000 km away, on the first day of the spill. Exxon acknowledged responsibility for the spill, expressed its regrets, and committed to cleanup the spill. After a short transition period, Exxon took over management of all response operations working under the direction of the U.S. Coast Guard Federal On-Scene Coordinator (FOSC).
Though this spill still remains the largest in U.S. history, the amount spilled ranks relatively low on the list of alltime worldwide spills - number 53 according to the latest data summary issued by Cutter Information Corp. (3). What made the VALDEZ spill noteworthy and led to such a massive response effort was the extent of shoreline impact (over 2,000 km), and the environmentally-sensitive area in which it occurred.
Exxon personnel arriving on the scene had 4 priorities (8). The highest and most immediate priority was to off-load 1 million barrels (about 160,000 t) of crude which remained on the VALDEZ - about 80% of the original cargo. Though the vessel was precariously balanced on Bligh Reef, Exxon experts worked closely with Coast Guard personnel to successfully transfer all the cargo to other tankers. This was later viewed as a major achievement, particularly because it was achieved over an 11 day period without injury of further loss of cargo despite 5 m tides and a major storm.
The next priority was identification and protection of sensitive environmental areas. All parties involved, including fishermen, developed a priority listing of valuable resources. At the top of the list were salmon hatcheries. The early boom deployment focused on the hatcheries and important salmon streams and the oil was kept out of those areas. This probably contributed to record salmon catches recorded in the years immediately following the spill. This was another very positive achievement.
The third priority was on removal of oil from the water. For this priority there were several disappointments, as summarized in the following section. Overall, only about 60,000 barrels (9,400 t) of emulsion containing about 25% oil content were collected by mechanical skimmers.
The fourth priority was the removal of oil from the shorelines.
