<P> 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 . </P> <P> 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 m) were recovered and 2,000,000 US barrels (240,000 m) to 3,000,000 US barrels (360,000 m) washed ashore, mainly in Saudi Arabia . </P> <P> More recent scientific studies have tended to disagree with this assessment . Marshlands and mud tidal flats continued to contain large quantities of oil, over nine years later, and full recovery is likely to take decades . </P> <P> Dr. Jacqueline Michel, US geochemist (2010 interview--transcript of radio broadcast): </P>

How long did it take to clean up the gulf war oil spill