Workers clean a beach after tar balls washed up as efforts continue to contain BP's massive oil spill in South Pass, Louisiana. Florida environmental authorities Wednesday declared a final emergency order ahead of the arrival in the state's northwest of the massive Gulf of Mexico oil spill.

Florida environmental authorities Wednesday declared a final emergency order ahead of the arrival in the state's northwest of the massive Gulf of Mexico oil spill.

The order is meant to speed up the measures that can be taken to try to protect and estuaries, Governor Charlie Crist's office said.

"Giving local government flexibility to prepare for the oil’s possible landfall and immediate relief to our businesses will help secure Florida’s economy and beautiful environment," the governor said.

Earlier he told the St. Petersburg Times: "This has the potential to be the largest single environmental and economic disaster in the history of Florida."

British Petroleum has pledged 25 million dollars in advance to Florida to try to step up the response to the disaster.

A streamlined "top hat" structure is the latest attempt by engineers to plug the Deepwater Horizon rig, 80 kilometers (50 miles) off Louisiana, which exploded on April 20, killing 11 workers, and sank two days later.