The Persian Gulf War oil spill is regarded as the third largest oil spill in history, resulting from the 1990 Iraqi invasion of Kuwait. On 23 January, Iraq dumped 400 million gallons of crude oil into the Persian Gulf, causing the largest offshore oil spill in history at that time. It was reported as a deliberate natural resources attack to keep U.S. Marine forces from coming ashore (Missouri and Wisconsin had shelled Failaka Island during the war to reinforce the idea that there would be an amphibious assault attempt). About 30-40% of this came from Allied raids on Iraqi coastal targets.

The Cause of Persian Gulf War Oil Spill

Iraqi forces opened valves at the Sea Island oil terminal and dumped oil from several tankers into the Persian Gulf. The apparent strategic goal was to foil a potential landing by US Marines. It also made commandeering oil reserves difficult for US forces.

The immediate reports from Baghdad said that American air strikes had caused a discharge of oil from two tankers. Coalition forces determined the main source of oil to be the Sea Island terminal in Kuwait. American airstrikes on January 26 destroyed pipelines to prevent further spillage into the Persian Gulf. Several other sources of oil were found to be active: tankers and a damaged Kuwaiti oil refinery near Mina Al Ahmadi, tankers near Bubiyan Island, and Iraq's Mina Al Bakr terminal.

Environmental Impact of Persian Gulf War Oil Spill

The Persian gulf war oil spill, which began on January 23, 1991, caused considerable damage to wildlife in the Persian Gulf especially in areas surrounding Kuwait and Iraq. Early estimates on the volume spilled ranged around 11,000,000 US barrels (1,300,000 m3). These numbers were however significantly adjusted downward by later, more detailed studies, both by government (4,000,000 US barrels (480,000 m3) to 6,000,000 US barrels (720,000 m3)) and private (2,000,000 US barrels (240,000 m3) to 4,000,000 US barrels (480,000 m3)) researchers.

The slick reached a maximum size of 101 miles (160 km) by 42 miles (68 km) and was 5 inches (13 cm) thick in some areas. Despite the uncertainty surrounding the size of the spill, figures place it several times the size (by volume) of the Exxon Valdez oil spill.

The New York Times reported that a 1993 study sponsored by UNESCO, Bahrain, Iran, Iraq, Kuwait, Oman, Qatar, Saudi Arabia, the United Arab Emirates and the United States found the spill did "little long-term damage": About half the oil evaporated, 1,000,000 US barrels (120,000 m3) were recovered and 2,000,000 US barrels (240,000 m3) to 3,000,000 US barrels (360,000 m3) washed ashore, mainly in Saudi Arabia.

More recent scientific studies have tended to disagree with this 1993 assessment. Marshlands and mud tidal flats continued to contain large quantities of oil, over ten years later, and full recovery is likely to take decades.

Dr. Jacqueline Michel, US geochemist (2010 interview – transcript of radio broadcast):

The long term effects were very significant. There was no shoreline cleanup, essentially, over the 800 kilometers that the oil – - in Saudi Arabia. And so when we went back in to do quantitative survey in 2002 and 2003, there was a million cubic meters of oil sediment remained then 12 years after the spill.... [T]he oil penetrated much more deeply into the intertidal sediment than normal because those sediments there have a lot of crab burrows, and the oil penetrated deep, sometimes 30, 40 centimeters, you know a couple of feet, into the mud of these tidal flats. There’s no way to get it out now. So it has had long term impact.

Dr. Hans-Jörg Barth, German geographer (2001 research report):

The study demonstrated that, in contrary to previously published reports e.g. already 1993 by UNEP, several coastal areas even in 2001 still show significant oil impact and in some places no recovery at all. The salt marshes which occur at almost 50% of the coastline show the heaviest impact compared to the other ecosystem types after 10 years. Completely recovered are the rocky shores and mangroves. Sand beaches are on the best way to complete recovery. The main reason for the delayed recovery of the salt marshes is the absence of physical energy (wave action) and the mostly anaerobic milieu of the oiled substrates. The latter is mostly caused by cyanobacteria which forms impermeable mats. In other cases tar crusts are responsible. The availability of oxygen is the most important criteria for oil degradation. Where oil degrades it was obvious that benthic intertidal fauna such as crabs re-colonise the destroyed habitats long before the halophytes. The most important paths of regeneration are the tidal channels and the adjacent areas. Full recovery of the salt marshes will certainly need some more decades.

The Financial Times, in reference to the April 2010 Deepwater Horizon oil spill in the Gulf of Mexico, cited the 1993 optimistic assessment of the Gulf War oil spill as evidence that "Initial warnings of catastrophic environmental damage from oil spills can turn out to be overdone".