Exxon Valdez

Starting Date 
Friday, March 24, 1989
tanker grounding
Prince William Sound, Alaska
Estimated Spillage 
11 million gallons (20% of total cargo)

The 1989 Exxon Valdez oil tanker spill is surpassed only by the 2010 Deepwater Horizon/Macondo well blowout in volume released into U.S. waters. Nevertheless, the officially estimated 11 million gallons of crude oil from the Prudhoe Bay oil field, devastated the pristine, remote Prince William Sound, Alaska area. (Some argue that a more accurate estimate is between 25 and 32 million gallons.)

While the captain slept below, the third mate piloted the tanker out of the shipping lanes to avoid icebergs and did not have radar to detect a radar reflector that was on the next rock inland from Bligh Reef, the site of the grounding. The radar was broken and had been disabled for more than a year. Numerous other errors contributed to the wreck and ruptured hull; according to the results of the National Transportation Safety Board, those factors were:

  • The failure of the third mate to properly maneuver the vessel, possibly due to fatigue and excessive workload;
  • The failure of the master to provide a proper navigation watch, possibly due to impairment from alcohol;
  • The failure of Exxon Shipping Compay to supervise the master and provide a rested and sufficient crew for the Exxon Valdez;
  • The failure of the U.S. Coast Guard to provide an effective vessel traffic system;
  • The lack of effective pilot and escort services.

Eight of the tanker’s 11 cargo tanks were punctured and spewed 5.8 million gallons of crude oil within the first three and one-quarter hours of the grounding. The 33° F temperatures with slight drizzle rain/snow mix, 10 knot winds, and 10 miles visibility during the night contributed to the immediate impact of the disaster.

Clean-up Efforts 

Exxon Corporation mobilized equipment and personnel to respond to the spill, but not in the first few critical hours and days. The U.S. Coast Guard did not demonstrate oil spill containment and response capabilities although it was effective in its role regarding ship salvage, crew protection, and lightering operations (ship to ship transfer of crude oil). Other state and federal agencies demonstrated varying capabilties and preparedness for such as disaster. NOAA provided spill trajectory, resources at risk, and early spill impact information during the initial stages of the spill, then shifted its focus to the effectiveness and environmental effects of cleanup technologies, and ultimately conducted a multi-year study of the environmental impacts.

At the peak of the clean-up effort there were 10,000 workers, about 1,000 boats, and approximately 100 airplanes and helicopters involved. Various techniques were used during the clean-up efforts, which were curtailed after more than four summers, although some beaches remain oiled to this day.

  • High pressure hot water treatment and cold water treatment: using fire hoses to wash the oil off and out of the rocky coves and to the shore where is would be trapped within several layers of boom and either be scooped up, sucked up, or absorbed using special materials. They were stopped after it was determined that the washing was causing more damage than the oil because it displaced and killed microbial populations, some the base of the food chain and some capable of facilitating the biodegradation of the oil.
  • Mechanical: On some beaches, backhoes and other heavy equipment tilled the beaches to expose the oil so it could be washed out.
  • Bioremediation: Many beaches were fertilized to promote microscopic bacteria growth that would eat the hydrocarbons, an effective technique where the oil was not too thick.
  • Dispersant: Initially, dispersant (Corexit 9580) was used, but there was not enough wave action to mix it with the oil in the water so it was discontinued.
  • Explosion: One trial was conducted early on to burn the oil, resulting in reducing a very small portion of the oil to removable residue. Weather conditions prevented any additional attempts.

Less than 10% of the oil was recovered. A NOAA study found that, as of early 2007, more than 26 thousand gallons of oil remain in the sandy soils of the shoreline, and it's declining at a rate of less than 4% per year. The rate of decline is even slower in the Gulf of Alaska. A NOAA study also found that the remaining oil generally lies below the surface of the beaches in sheltered areas where minimal wind and wave action failed to break down and remove stranded oil and on beaches where oil initially penetrated very deeply and was not removed.

"We know that oil remains in Prince William Sound. The extent to which it may be having an adverse impact is subject to debate and investigation, but for some people the fact that it remains at all is evidence that recovery has not taken place." (NOAA web site, August 2, 2012)


Although no human life was lost as a direct result of the grounding, four deaths occurred during cleanup operations. Widespread health problems among cleanup workers were ignored and, for many, dismissed by Exxon as "the Valdez Crud." A reported 6,722 cases of respiratory claims from cleanup workers were deemed "colds or flu," and an exemption under OSHA's hazardous waste cleanup reporting requirements was invoked. Many are still disabled, or have died, as a result of their exposure to the toxic oil and oil fumes.

Many consider the Exxon Valdez spill the worst worldwide in terms of damage to the environment. The essentially pristine, remote wilderness area in which it occurred as well as the timing of the incident and the abundance of wildlife in the area contributed to its intense impact. Fisheries, subsistence livelihoods, tourism, and wildlife all suffered.

The spill stretched 460 miles, and 1,300 miles of shoreline were impacted by the oil. Two hundred miles were heavily or moderately oiled (obvious), and 1,100 miles were lightly or very lightly oiled (light sheen or occasional tarballs).

The assessment of the damage and long-term impacts is ongoing, and some species have yet to recover. The immediate effects include deaths of seabirds (100,000 - 250,000), sea otters (2,800 or more), river otters (12 or more), harbor seals (300 or more), bald eagles (247), and orcas (22). Billions of salmon and herring eggs were destroyed; the herring population subsequently collapsed. Other populations declined, and the cascading effects were significant. For instance, widespread tissue contamination concentration (PAH) elevations was observed in invertebrates like mussels and clams.

Because orcas (killer whales) had been studied quite extensively prior to the spill, they stand out as examples of some of the disastrous impacts of the spill. Two pods (one resident and one transient) were observed swimming through the oil. In the year and a half after the spill, both pods had unprecedented high rates of death (33% for resident and 41% for transient), including immature whales and breeding females. As of 2012, NOAA reports that the resident population has not reached pre-spill numbers, and the transient population has dropped so low that it has been listed as a depleted stock under the Marine Mammal Protection Act. All the while, other Southeast Alaska killer whale populations have been growing since the mid-1980s. (See NOAA web report.)