Drilling Rigs in the Gulf
Unused oil rigs sit in the Gulf of Mexico near Port Fourchon, Louisiana in this file photo. Reuters

The Bureau of Safety and Environmental Enforcement announced the source of a 10-square mile oil sheen in the Gulf of Mexico was likely a naturally occurring oil seep from the ocean floor, not a spill from an oil rig.

The bureau said that an underwater vehicle deployed by Shell surveyed the area and found oil seeping naturally from the ocean floor. The BSEE said, however, it is working to confirm the seep as the origin of the 10 square mile oil sheen first reported Thursday.

The sheen is located roughly 130 miles south east of New Orleans and is near two Royal Dutch Shell platforms, but the findings by the underwater remote operated vehicle (ROV) quieted fears the oil was due to Shell drilling or oil production activities.

The sheen is dissipating, said Shell, and is the size of roughly six barrels of oil.

Shell made a point of emphasizing it had not experienced any incidents at its platforms in the vicinity of the oil sheen.

We worked closely with our sister agencies to coordinate our efforts as Shell mobilized their ROVs to investigate the source of the sheen, BSEE Director James Watson said. We appreciate Shell's diligence in responding, as well as the efforts of the men and women of BSEE who continue to work hard to quickly resolve this situation.

The Gulf of Mexico is especially rich in oil and natural gas. The Bureau of Ocean Energy Management keeps track of known seeps from which oil and sometimes natural gas escape. Using data already available to the departments and Shell, the ROV was able to locate the seep, and confirm that oil was escaping through it.