PORT SULPHUR, La. (AP) - Oil from the Deepwater Horizon disaster remains in marshes off the coast of Louisiana, where officials renewed complaints Friday about the cleanup effort by BP and the federal government.

State and parish officials took media on a boat tour of Barataria Bay, pointing out areas where oil is collecting in marshes and protective boom is either absent or overwhelmed by the oil.

"This is the biggest cover-up in the history of America," said Plaquemines Parish President Billy Nungesser, who was accompanied by Robert Barham, the secretary of Louisiana's Department of Wildlife and Fisheries.

Nungesser has been a frequent and outspoken critic of the cleanup effort ever since oil from the April 20 accident began infiltrating the environmentally delicate Louisiana coast line.

A Coast Guard official who tagged along on the tour said a plan was being developed to clean up the rapidly eroding marsh. However, he had no details and couldn't explain why there is no mechanism in place to keep the situation from getting worse eight and a half months after the disaster and almost six months after the flow of oil was stopped.

 "Clearly there is oil here in the marsh but we are working as a team to find a best way to clean it up," said Coast Guard Lt. Cmdr. Dan Lauer.

 The April explosion that destroyed the BP-leased Deepwater Horizon rig killed 11 workers and, according to government estimates, led to more than 200 million gallons of oil spewing from a hole a mile beneath the Gulf of Mexico. BP PLC disputes the figure, but has yet to provide its own.

Aside from the damage done to tourism when the oil hits Gulf Coast beaches, there are numerous environmental concerns. Among them is the damage done to the delicate reeds and grasses that grow in Louisiana's coastal estuaries. The marshes serve as nurseries for a variety of microscopic sea life - the bottom of the food chain that replenishes abundant Gulf fisheries.

Also, the killing of marsh grasses contributes to a long-standing erosion of Louisiana's coast and barrier islands, the state's first line of protection against hurricanes. (Copyright 2011 by The Associated Press. All Rights Reserved.)