NEW ORLEANS (AP) — The Coast Guard says it has approved plans to investigate another oil sheen spotted near the site of BP's 2010 Deepwater Horizon disaster.

The sheen was spotted earlier this month, days after the company plugged an abandoned piece of equipment that was believed to be the source of an earlier sheen.

Coast Guard Ensign Glenn Sanchez said Thursday the oil from the sheen has been tested and is from the Macondo well where the disaster occurred. However, he stressed that the oil is classified as old or "dead" oil that has been trapped on the sea floor since the accident, not fresh oil leaking from the well site that was secured in 2010.

Robot submarines will inspect the rig's wreckage and other places near the blowout site next week.