A tropical depression formed over the Gulf of Mexico on Tuesday on a track likely to take it near BP Plc's massive oil spill site before it makes landfall in Louisiana.
The US National Hurricane Center said the depression, packing top sustained winds of 35 miles (55 km) per hour, was located about 375 miles (600 km) southeast of the mouth of the Mississippi River.
As a precautionary measure, the approaching storm has already prompted BP to delay final work on a relief well to permanently kill the source of the world's worst offshore oil spill by two to three days.
Computer models forecast the tropical depression will move northwest, crossing the spill site before making landfall in southeast Louisiana on Thursday.
