Photos of the Gulf Oil Spill, One Year Later

At least 1,000 barrels of oil a day are still leaking out of the Deepwater Horizon well

April 20 marks the one-year anniversary of the worst environmental disaster in U.S. history, and oil continues to leak out of the Deepwater Horizon wellhead at an estimated rate of 1,000 to 5,000 barrels a day. And there are still the disturbing, if familiar, signs of the disaster's lasting impact: the dead sea turtle above was found on a beach in Waveland, Mississippi on April 14, 2011. There have been an estimated 67 sea turtle deaths in Mississippi.

Last week, emails obtained pursuant to the Freedom of Information Act revealed that BP officials plotted how to influence scientists assessing the damage of the spill, Guardian reported. Russell Putt, a BP environmental expert, asked colleagues in an email dated 24 June, 2010, "What influence do we have over the vessels/equipment driving the studies vs. the questions?" Such conversations do little to assuage the fear that BP has had too much control over studies into the impact of the oil spill, pictured below, one year later.

A sand berm built to capture oil from the BP spill is seen at an oil cleanup site in Barataria Bay, Louisiana on April 13, 2011.

Workers clean oil leftover from the spill in the Gulf of Mexico on March 10, 2011 at Pensacola Beach, Florida.

Tarballs from the BP oil spill are seen in a worker's net after being collected on Waveland beach, Mississippi on December 6, 2010, nearly eight months after the spill.

Migratory white pelicans take off from the shoreline of an island battered by oil on December 5, 2010, in Barataria Bay, Louisiana, nearly eight months after the spill.