The Exxon Valdez Oil Spill: History and Impact

Teams of firefighters cleaning the Alaskan coast following the Exxon Valdez oil spill.

 Jean-Louis Atlan / Getty Images

The Exxon Valdez oil spill in 1989 was the largest oil spill in the U.S. (10.8 million gallons) and one of the largest in the world — until it was topped by the Deepwater Horizon spill in 2010, which discharged 134 million gallons of oil. The environmental catastrophe happened in Prince William Sound, Alaska, a location notoriously hard to reach, which made it very difficult to respond to the spill quickly and effectively.

The Exxon Valdez oil tanker — which gives the oil spill its name — left the Prudhoe Bay oil field on Alaska's North Slope carrying 53 million gallons of oil. Its final destination was to be Long Beach, California, but the tanker ran into a reef just hours after departing Valdez, Alaska.

The spill had both immediately devastating and long-lasting effects on the environment, negatively affecting both human lives and wildlife. Alaskan waters are home to sea otters, salmon, seals, and seabirds, and the spill killed tens of thousands of them, as well as many other animals. In total, the spill affected 1,300 miles of coastline.

Exxon Valdez Oil Spill Facts

  • On March 24, 1989, the oil tanker Exxon Valdez ran into a reef, spilling 10.8 million gallons of crude oil into Alaskan waters.
  • The oil spill happened in Prince William Sound, Alaska, located on the south coast of the state, 100 miles from Anchorage.
  • The collision was the result of a number of factors, including crew fatigue, incorrect navigation of the tanker, and improper maintenance of the collision-avoidance radar system.
  • After four years of work, only about 14% of the oil spilled was cleaned up through human actions.

The Oil Spill 

The spill started on March 24, 1989 at 12:05 a.m. when the oil tanker, which had left the Alyeska Pipeline Terminal in Valdez, Alaska, a few hours earlier, hit a reef in Prince William Sound. According to a National Oceanic and Atmospheric Administration (NOAA) report, within 30 minutes of the initial impact, the chief mate found that all center and starboard cargo tanks were discharging oil into the Sound. Other tanks were damaged and the whole ship's stability was in question.

By the time U.S. Coast Guard investigators boarded the Exxon Valdez — just four hours after it had run aground — 7 million gallons had already been released. By about 6 a.m., 9 million gallons of oil were already dispersed in the Prince William Sound, and ultimately 10.8 million gallons were spilled.

Causes of the Spill

While the initial blame for the spill fell on the captain of the Exxon Valdez, Joseph Hazelwood, he was found not guilty of the felony charge in a 1990 court trial. He was found guilty of a misdemeanor and had to complete community service.

The National Transportation Safety Board (NTSB) found five main causes for the spill:

  1. Excessive workload which caused fatigue. The third mate failed to properly drive the ship due to lack of sleep the previous night coupled with working a "stressful, physically demanding day."
  2. Improper navigation watch by the master in charge at the time.
  3. Exxon Shipping Company's failure to ensure master was properly supervised and provide enough rest time for crew (and number of crew so this could happen).
  4. Failure in the U.S. Coast Guard's vessel traffic system.
  5. Ineffective pilot and escort services.
Tanker Pumping Oil From Exxon Valdez
Tanker pumping oil from the Exxon Valdez. Bettmann Archive / Getty Images

Initial Reaction and Cleanup 

By the time the sun rose on March 24, the huge size and significant cleanup needed was already obvious from flyover surveys. Initial response for containing the oil from traveling was slowed by lack of equipment and workers out on holiday breaks from the Alyeska Pipeline Terminal. When people did arrive to help, they determined that the only barge that was nearby to help with containment was under repair. 

For these and other reasons, the NOAA report states that the hours after the spill were, "a nightmare of poor preparedness and execution that had been forewarned and foretold at least five years prior to 1989 by both the Alaska Department of Environmental Conservation and the U.S. EPA."

Chemical Dispersants and Burning

Boats and sorbent boom circle the Exxon Valdez oil spill in Prince William Sound, Alaska, USA, to control the spreading slicks
Boats and sorbent boom circle the Exxon Valdez oil spill to control the spreading slicks.

Natalie Fobes / Getty Images

Due to the challenges of the area, including a rugged coastline, remote location, sensitive wildlife habitat, and fisheries, newer, less-tested cleanup methods were employed right away, including chemical dispersants. There are concerns about dispersants pushing oil into the water column where it can hurt other organisms, so it's not a perfect solution, but it can help keep oil off animals on the surface of the water.

The first round of chemical dispersant Corexit 95271 was applied from a helicopter and missed most of the target area. Six more applications of the dispersant were made between March 24 and 28, and three more were tried in April, but monitoring tests showed "no significant benefits" from the dispersant being used. A total of about 45,000 gallons of dispersant was sprayed.

Some of the oil was burned off, and this was found to be a more successful method of getting rid of oil than dispersants. The first test burned off about 15,000 gallons of spilled crude oil, and plans were made to use the technique in other areas, but a storm system on March 27 spread the oil slick — which had been one big connected bunch of floating oil — far and wide, so burning was no longer a viable option.

As hours and days ticked by, the oil became more difficult to clean up than if it had been contained quickly after the spill. Over the months following the spill, storms, wind, and ocean currents distributed the spilled oil over 1,300 miles of shoreline, from the reef in Prince William Sound to the Gulf of Alaska.

Environmental Impact 

The spill had both acute, short-term impacts on wildlife and environmental health, and long-term effects that persist to the present day.

4/3/1989-Prince William Sound, AK- Fisherman John Thomas holds an oil slicked sea bird recovered near Green Island in the Prince William Sound, as efforts continue to help the animals suffering from the effects of the worst oil spill in U.S. history.

Bettmann / Getty

Short-Term Impact

A variety of wildlife in Prince William Sound and those that lived or used the rocky intertidal shorelines were partially or wholly covered in toxic crude oil in the days following the oil spill. According to the NOAA report, wildlife loss estimates include "250,000 seabirds, 2,800 sea otters, 300 harbor seals, 250 bald eagles, up to 22 killer whales, and billions of salmon and herring eggs.” However, it's difficult to know the exact number of animals killed by the spill because most dead bodies in the water sunk.

While marine mammal experts thought whales and orcas would stay away from an oil spill, which would reduce their exposure to toxins in the water, orcas were seen in the oil, next to the tanker, and close to oil-skimming operations.

Environmental Legacy of the Oil Spill

Beached Gray Whale
A dead gray whale lies on the beach at Kodiak Island, Alaska, after the Exxon Valdez oil spill.

Corbis / Getty Images

Despite the efforts of 10,000 workers, 1,000 vessels, 100 aircraft, and four years of work, only about 14% of the oil spilled was cleaned up through human actions.

According to the Exxon Valdez Oil Spill Trustee Council, a group of state and federal trustees in charge of working with the public and scientists to oversee the spending of the $900 million that Exxon was forced to pay in cleanup costs, the oil lingered far longer than expected. After a two-year cleanup process, it was thought that natural processes would remove the rest of the oil from the environment. That didn't happen, and the oil along shorelines lingers to the present day, including some which has "retained its initial toxicity."

The Trustee's report states: "Scientists studying the fate of the oil estimated (that) 20% evaporated, 50% biodegraded, 14% was cleaned up, 13% remained in subtidal sediments, 2% remained on shorelines, and less than 1% remained in the water."

Long-Term Impact on Wildlife

Long-term impacts of the oil spill are still being studied and understood, but seabirds, sea otters, killer whales, and animals in the subtidal communities have all been affected. Studies funded by the Trustee Council found that long-term harm done to these animals "may equal or exceed acute injury at the time of the Spill."

Monitoring of orca populations revealed "circumstantial but compelling evidence for profound effects that may lead to extinction in one orca subpopulation." Sea otter populations were negatively affected for at least 10 years after the spill, since oil exposure led to lung, liver, and kidney damage for those animals it didn't immediately kill. In addition, the high-pressure water hoses used to move oil off beaches destroyed the complex layers of sand and sediment that support the bivalves that otters eat.

Less obvious impacts included fish exposure to hydrocarbons during early life stages. Pink salmon has mostly rebounded, but herring levels still haven't. Seabirds that depended on specific types of fish that were killed or whose population numbers were depressed suffered their own population declines due to lack of food.

The persistence of oil in the environment has, according to the Trustee Council's report, slowed the recovery of some wildlife.

Rescue Crews Recovering Dead Sea Otters
Recovery crews pick up dead sea otters along Green Island, Alaska, 1989.

Bettmann / Getty Images

Other Long-Term Impacts

The impacts on the environment and wildlife aren't the only long-lasting consequences of the Exxon Valdez Oil Spill.  

Economic impact

The word "devastating" is often used in reference to the impact the oil spill had on the fisheries and the tourism industry in Alaska.

Salmon and herring fisheries lost income not just in 1989, but were hardest hit in 1993, when the eggs that had been laid — and destroyed by the spill — would have reached adulthood. One estimate puts the cost at $300 million of economic harm to more than 32,000 people whose work depends on fisheries.

According to the Indigenous peoples in the region, their livelihoods and way of life has been forever altered.

USA, Alaska, Prince William Sound, Exxon Valdez oil spill on shore
Prince William Sound, Alaska. The black mark of oil on the shore can be seen years after the Exxon Valdez oil spill. Chip Porter / Getty Images

It's hard to put a number on the value of the thousands of animals that were killed by the spill, but there were some estimates made for the per-unit replacement cost of seabirds, mammals, and eagles: that value was $2.8 billion.

Tourism spending decreased by 35% in southwest Alaska in the year following the spill and visitor spending resulted in a loss of $19 million to the Alaskan economy.

Two years after the Exxon Valdez spill, the economic losses to recreational fishing were estimated to be $31 million.

Costs to Exxon

Exxon spent over $3.8 billion to clean up the oil spill, which covered paying people directly to do jobs like wash off wildlife and spray oil-covered beaches, but also compensated 11,000 local residents for income loss. That amount also included fines.

However, in 1994, an Anchorage jury found that Exxon's recklessness should be recognized and awarded spill victims $5 billion in damages. Exxon appealed the decision, which was halved in an appeals court. They kept appealing, spending 15 years in court, until the case reached the U. S. Supreme Court in 2006. The Supreme Court reduced the punitive damages awarded to $507 million — about 12 hours' worth of revenue for the company.


In 1990, the U.S. Congress passed the Oil Pollution Act (OPA), which required a phase-out of oil tankers with just a single hull. The idea was that a double hull could hold its oil contents if the exterior hull were breached.

The OPA also set up a trust fund financed by a tax on oil. It is available "to clean up spills when the responsible party is incapable or unwilling to do so."

Industry Practices

In addition, the OPA requires oil tankers and other oil storage locations to create plans to detail what they'll do in response to large oil spills. There should also be area contingency plans to prep for oil spills on a regional scale.

The Coast Guard has published specific regulations for oil tankers and it has a satellite tracking system to monitor ships in the area. There are also specific tug boats that guide oil tankers in and out of Valdez to the Pacific Ocean.

View Article Sources
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