BP oil spill
© Reuters/Lee Celano
The U.S. Coast Guard is investigating an oily sheen spotted in the Gulf of Mexico last month near the site of the 2010 Deepwater Horizon oil spill 40 miles south of the Mississippi River, a spokesman said Wednesday. Samples of the sheen taken near the site of the failed BP Macondo oil well have been sent to the service's Marine Safety Lab in Groton, Conn., to determine whether the oil is from the BP spill, said Lt. Commander Michael Wolfe.

The Coast Guard's National Response Center was first notified of the sheen on Sept. 16 in a report that said it was spotted on satellite imagery, and had not been visually confirmed.

"Attempting to confirm presence of sheen via visual observation and further satellite data collection," said that first report. "BP intends to mobilize a helicopter overflight of the area as soon as possible."

The sheen was later reported on a new National Oceanic and Atmospheric Administration web site tracking environmental incidents nationwide.

"Although the source of these sheens may be the wrecked BP Macondo well, this relationship has not been established at this time," officials wrote on the site, which is operated by the National Ocean Service's Office of Response and Restoration. "Activities include daily over-flights sponsored by BP, with USCG or NOAA observers on board intermittently."

The report also said BP was sending a vessel equipped with a remotely-operated underwater vehicle to the area to investigate the potential source of oil.

A BP spokesman referred questions about its response to the sheen to the Coast Guard.

This is the latest in a series of reports of new oil on the surface of the Gulf at or near the site of the Deepwater Horizon explosion, which resulted in a 3-month release of oil.

Coast Guard officials said they also are monitoring a 3-mile by 1-mile "barely discernible silvery sheen" emanating from an Apache Corp. platform about 15 miles south of Grand Isle.

A report filed with the Coast Guard National Response Center by Apache officials on Tuesday said 7 gallons of oil were released into the Gulf because of equipment failure. A separate report filed with the center by an anonymous caller referred to the release as a "massive oil sheen."

Wolfe said according to the company, the equipment has been secured and the oil in the water is not recoverable. He added that the Coast Guard has referred the case to the EPA, and there is no chance of the oil reaching land.