Crude oil prices soared to record highs of $70.80 a barrel because of Hurricane Katrina's feared impact on crude oil production in the Gulf of Mexico.
Prices eased slightly in later trading.
About one-quarter of U.S. crude oil production comes from the Gulf coast area, and many key refineries and import facilities are on land nearby.
Last year, a different hurricane damaged energy facilities in the same area, prompting oil prices to jump 22 percent in one month.
U.S. oil refineries have been having trouble meeting rising oil demand, and analysts say production slowdowns could spark even higher prices.