Oil giant BP has said the damage and disruption caused by Hurricanes Katrina and Rita is likely to cost it more than $700m (£399m).
The hurricanes caused major disruption for all oil firms
BP said trading conditions in the third quarter were "significantly impacted" by Katrina and Rita, which hit oil output in the Gulf of Mexico.
Disruptions cut oil output by about 300,000 barrels a day while costs were incurred in clean-up and damage repair.
BP's largest US refinery is located on the outskirts of Houston, Texas.
The Texas City refinery and other BP facilities in the area were shut for several days before the two hurricanes struck and also in the immediate aftermath.
BP also saw reduced margins on the marketing of petroleum after disruptions to the refinery network pushed up wholesale prices sharply.
"The trading conditions experienced by BP in the third quarter of 2005 were significantly impacted by Hurricanes Katrina and Rita and their aftermath," the company said in a statement.
The company added that it had cost $100m to secure and repair its Thunder Horse drilling platform which was left listing after Hurricane Dennis passed through the Gulf of Mexico in July.
BP's shares closed 18 pence, or 2.67%, lower at 655.5p on the London market on Tuesday.