FILE - This April 27, 2010 file photo shows an oil rig in the Gulf of Mexico near the Chandeleur Islands, off the Southeastern tip of Louisiana. From above, five years after the BP well explosion, the Gulf of Mexico looks clean, green and whole again, teeming with life: a testament to the resilience of nature. But there's more than surface shimmering blue and emerald to the aftermath of the Deepwater Horizon spill. And it's not nearly as pretty a picture, nor as clear. (AP Photo/Gerald Herbert, File)