A day after a huge oil sheen was reported south of Grand Isle, nothing has come into clearer focus. The Coast Guard is now classifying the mystery sheen as a mystery substance, but, as ever, the proof may come from what rolled up on the beach. In a statement, the Coast Guard said samples of the stuff creating a large sheen contained "only trace amounts of petroleum hydrocarbons, oil and grease," and was apparently the result of a lot of movement at the mouth of the Mississippi.
"At this point, the dark substance is believed to be caused by a tremendous amount of sediment being carried down the Mississippi River due to high water, possibly further agitated by dredging," the statement said.
However, the Coast Guard also said an "oily substance" was observed washing ashore on Elmer's Island, Grand Isle and Port Fouchon.
"Currently, the west end of Grand Isle, the east and west end of Elmer Island, and intermittent areas of Fourchon Beach have been impacted."
There were also reports of something resembling an oil slick in Timbalier Bay.
The statement said no samples were taken of that substance, and it is not believed to be "residual oil from the Deepwater Horizon." Yet, the Coast Guard deployed 25,000 feet of boom and activated spill response procedures.
And, because everyone is on this here Internet, the sheen now has a Twitter.