The Exxon Valdez Oil Spill
The Exxon Valdez Oil Spill 4
In an attempt to reduce U.S. oil imports, a consortium of oil companies announced plans in 1969 to construct a pipeline from Alaska's North Slope to Valdez, an ice-free port on the southeastern coast of Alaska. Federal approval for the 800-mile Trans Alaska Pipeline System (TAPS) was obtained in 1973, and the first oil tanker shipment originated from Valdez on August 1, 1977. It has been estimated that 75 tankers visit Valdez every month. Currently, crude oil from Alaska's North Slope accounts for roughly 25% of total U.S. oil production. During the past 18 years approximately ten billion barrels (in excess of 400 billion gallons) of North Slope crude have been transported by TAPS to the Port of Valdez.
Shortly after midnight on Friday, March 24, 1989, the Exxon Valdez, a three-year-old 987-foot tanker carrying 1.25 million barrels (50 million gallons) of North Slope crude, ran aground on Bligh Reef in Alaska's Prince William Sound. The Exxon Valdez left the Port of Valdez at 9:21 pm on March 23, 1989. After navigating the tanker through Valdez Narrows into Prince William Sound (PWS), the harbor pilot had transferred command back to Captain Hazelwood at approximately 11:30 pm. Due to floating ice from the Columbia Glacer, Hazelwood had received permission from the Coast Guard to divert from the Southbound (western) lane of the Traffic Separation Scheme to the Northbound (eastern) lane. Rather than opting to reduce speed and allow the vessel to navigate the ice flow, however, Hazelwood chose to enter the 0.9 mile gap between the edge of the ice and Bligh Reef at accelerating speed. This course, a more severe detour outside the Traffic Separation Scheme, allowed little tolerance for error. Before retiring to his cabin at 11:53 pm, Hazelwood turned navigation over to the Third Mate with a command to make a right turn (to avoid Bligh Reef) when the ship was abeam the Busby Island light. At 12:04 am, the Exxon Valdez shuddered as it grounded on Bligh Reef. However, the radio distress call to the Coast Guard was delayed until 12:27 am.5
As a result of the grounding, eight of the vessel's eleven cargo tanks were ruptured. The resulting oil spill of 258,000 barrels (10.8 million gallons), or 20% of the ship's cargo, was the 34th largest in the world at the time and the largest in U.S. waters. Successful off-loading of the remaining 1 million barrels of oil was completed on April 4. While the waters of PWS were relatively calm in the immediate aftermath of the spill, a severe storm that commenced the third day after the spill had the effect of driving the spilled oil toward the shoreline at the southwestern end of PWS. The data in Table 4 (see map, Figure 3) on the chronology of the oil spill illustrate the effect of the storm on the spread of the oil spill.
While the Alyeska Pipeline Service Company, the consortium of seven major oil companies that operates TAPS and the Valdez terminal, was legally charged with the responsibility of oil spill cleanup, budget-tightening measures introduced in 1981 had resulted in a partial dismantling of the oil spill response team. Due to the delay in oil spill response caused by this curtailment of personnel, the first Alyeska barge, loaded with 50,000 pounds of boom (floating barrier used for containment) and skimmers, did not arrive at Bligh Reef until 2:30 pm, more than 14 hours after the accident. It has been estimated that most of the oil released from the Exxon Valdez into PWS had already escaped from the vessel by 5:30 pm the day of the spill.
Overseeing the cleanup operation spearheaded by Exxon Co. was the Coast Guard at the federal level and Alaska's Department of Environmental Conservation (DEC) at the state level. However, mounting a cleanup campaign from Houston, TX, caused unfortunate delays although mobilization of equipment was initiated as early as 4:00 am Alaska time on March 24, 1989. Frank Iarossi, a graduate of the U.S. Coast Guard Academy and president of Exxon Shipping, arrived in Valdez at 5:37 pm on March 24 to assume control of the cleanup operation despite the fact that Alyeska was charged with full responsibility for oil spill cleanup in the contingency plan.5 This outcome was consistent with federal law that makes the polluter responsible for the cleanup unless that organization has insufficient resources, in which case the U.S. government (the Coast Guard in the case of offshore spills) intervenes.6
Figure 3. Map of Prince William Sound (PWS) and the South-central Gulf of Alaska (GOA)
Source: Environ. Sci. Technol. 1991, 25, p 203.
|Day #||Date||Oil Front (MI)||Farthest Reach|
|4||March 27, 1989||40||Block Island (PWS)|
|7||March 30, 1989||90||Montague Strait (PWS)|
|11||April 3, 1989||140||Kenai Peninsula (GOA)|
|19||April 11, 1989||250||Northern tip of Kodiak Island|
|40||May 2, 1989||350||Southern range of Kodiak Island|
|56||May 18, 1989||470||Alaskan Peninsula|