A natural gas explosion sunk the Deepwater Horizon oil rig in the Gulf of Mexico in April 2010. The accident killed 11 rig workers and oil spilled into the sea for much of the summer.
Activists protested BP's annual general meeting in London saying the company hadn't done enough to address the spill, one of the worst such accidents in the history of the energy industry.
"The oil is not gone," Derrick Evans, an adviser from Gulf Port Mississippi for the Gulf Coast Fund, was quoted by The Guardian newspaper in London as saying. "It is very evident to me that the general perception is that BP made a big mess and BP did a big cleanup and that normalcy has returned. I'm here to tell you nothing could be further from the truth."
The U.S. National Wildlife Federation this week said there were "unknown" effects at coastal areas in and around the Mississippi River Delta. Demonstrators in London accused BP of "cutting corners" in its spill response.
BP defended its efforts, noting the company has spent more than $20 billion in its response to the April 20, 2010, oil spill.