Oil is washing up along the Gulf Coast in the wake of Hurricane Isaac, confirming concerns that the storm could churn up oil in the Gulf of Mexico. A Greenpeace research team took samples from beaches along the Alabama coast on September 2, including from an area with hundreds of tar balls in the Bon Secour National Wildlife Refuge.

Hundreds of tar balls on the beach at Bon Secour National Wildlife Refuge, Alabama on September 2, 2012

According to the US Coast Guard, oiled pelicans and other wildlife have been found in Louisiana marshes as well. As people struggle with flooding, wind damage, and power outages in the wake of the hurricane, officials have expressed concerns that on top of that disaster, Hurricane Isaac may stir up oil from the BP spill:

“This is another disaster on top of the hurricane that we’re going to have to deal with,” Garret Graves, chairman of Louisiana’s Coastal Protection and Restoration Authority, told The Huffington Post. “The threat is not insignificant.”

Up to 1 million barrels of oil are estimated to remain in the Gulf of Mexico. That oil remains, Graves said, because BP has failed to clean it all up in the more than two years since the tragedy. “That’s four to five times the oil that was spilled with the Exxon Valdez,” he added.

One of the tar balls on the beach at Bon Secour National Wildlife Refuge, Alabama on September 2, 2012

Meanwhile, officials in Washington DC are calling on federal agencies to provide an update on their oil spill cleanup efforts in the wake of Hurricane Isaac:

Rep. Edward Markey (D-Mass.) wants two federal agencies to explain how they will address lingering oil contamination from the 2010 explosion of the BP Deepwater Horizon drilling rig.

Markey told the heads of the Environmental Protection Agency (EPA) and the National Oceanic and Atmospheric Administration (NOAA) in letters sent Friday that Hurricane Isaac makes the Gulf of Mexico cleanup effort imperative.

Hundreds of tar balls on the beach at Bon Secour National Wildlife Refuge, Alabama on September 2, 2012