Crude prices fell for the second day on Tuesday as concerns over the swine flu outbreak weighed the markets.
The swine flu virus which has killed more than 100 people in Mexico has spread to more countries. The number of confirmed human swine flu cases in the United States has risen to 64 on Tuesday.
Investors are worrying that the outbreak of swine flu could curb the global economy recovery and further depress fuel demand.
The prices were also dragged down by a forecast on U.S. crude inventories. Analysts said the U.S. inventories would rise 2.1 million barrels last week due to slumping demand.
Light, sweet crude futures for June delivery was down 22 cents to settle at 49.92 U.S. dollars a barrel on the New York Mercantile Exchange. London Brent fell 33 cents to 49.99 dollars a barrel.