NEW ORLEANS - BP will no longer be responsible for cleaning up oil that winds up on shores of the Gulf Coast unless officials can prove it comes from the company's well that blew out in 2010, causing the worst offshore spill in U.S. history, according to a plan approved by the Coast Guard and obtained by The Associated Press on Tuesday.

The plan marks the near end of the cleanup phase of the oil spill, according to the Nov. 2 agreement. Now, BP will turn its attention to restoring areas damaged by the spill that began on April 20, 2010, when the Deepwater Horizon drilling rig exploded, killing 11 workers. About $1 billion has been set aside for those projects, an official says.

About 90 percent of the Gulf coast has been deemed clean, according to officials. The plan spells out protocol for when an area still needs to be cleaned and when BP's responsibility for that ends.

Louisiana officials wouldn't give their approval because they were concerned about what they perceived as a lack of long-term monitoring in the document. They also complained that the Coast Guard gave them only five days to review the plan, according to a letter sent to the agency by Garret Graves, a top aide to Gov. Bobby Jindal for coastal affairs.

That concern was echoed by Ralph Portier, an oil spill cleanup expert with Louisiana State University.

"If we have learned anything from Valdez and Ixtoc, there needs to be an awareness for long-term monitoring," Portier said.

He was referring to the Exxon-Valdez tanker spill in 1989 in Alaska and the 1979 Ixtoc oil rig spill in the Gulf of Mexico. He said the Coast Guard should have a plan to respond to problems that may arise.

Despite the concerns, the Coast Guard said its finalized plan would apply to Louisiana and all the Gulf states.

New oil that shows up on clean shores would be treated "as any kind of oil response," said Coast Guard spokeswoman Lt. Suzanne Kerver. Officials would try to determine where it came from. If a link to BP's now-plugged Macondo well was found, then the Coast Guard would ask the oil giant to clean it up.

Kerver says the shoreline plan outlines "the standard for clean."

BP can now start work on restoring areas damaged by the spill. Restoration plans could entail plantings, placing new sand on beaches and establishing new marsh.

"This is an important milestone in the recovery process for the Gulf Coast," said Mike Utsler, head of BP's Gulf Coast Restoration Organization. Utsler said BP has set aside $1 billion.

The company is responsible to try to fix the plant and wildlife ecosystems that were disrupted by the spill.

"We still have ongoing cleanup in sensitive wildlife nesting habitat and archeological sites," said Coast Guard Capt. Julia Hein, the federal on-scene coordinator. "However, there are significant portions of our coastline that are ready to move into the next phase, so that the Gulf Coast can start restoration projects critical to help heal the region."

Edward Owens is a technical adviser for BP and a veteran of the cleanup of the 1989 Exxon Valdez spill in Alaska. He said the Gulf cleanup was in its final stages.

"We call it the polishing stages, where you try to get that nice shine on your car," he said.

Under the plan, the cleanup standards will depend on the terrain.

A bit more oil will be allowed to remain on remote wild beaches where intense cleanup could do more damage. On beaches where people live and play, BP will be off the hook once there is no visible oil or oil is "as low as reasonably practicable" to clean up.

Marshes will be deemed clean when there is no thick oil left or when officials decide that it's best to let nature clean up the mess.