A slick of crude oil floated on the Gulf of Mexico today after an underwater pipeline was ruptured by an eight-ton anchor dropped accidentally from a drilling rig.

The slick was floating slowly westward, about 115 miles south of New Orleans and 75 miles south of the closest land, and did not pose an immediate threat to coastal areas, Coast Guard spokesman Jason Neubauer said.

No dead birds or fish had been spotted.

Airplanes were used to spread a chemical to disperse the oil, and five oil recovery boats were sent to the area, Neubauer said.

About 94,000 gallons of oil poured into the water on Friday, creating a slick two miles long and two miles wide. Today, the slick was roughly the same width but had stretched to seven miles, Neubauer said.

The drill rig was being towed to a new location Friday when the anchor dropped into water 440 feet deep and snagged the pipeline, dragging it and causing several breaks, Neubauer said.

The pipeline, owned by Equilon Pipeline Co. of New Orleans, was shut down after monitoring systems detected a pressure drop, said Mary Dokianos, a spokesman for Shell, which is a partial owner of Equilon.