NEW ORLEANS — Crews geared up to set fire to oil leaking from the site of an exploded drilling rig in the Gulf of Mexico on Wednesday, a last-ditch effort to get rid of it before it reaches environmentally sensitive marshlands on the coast.
A 500-foot (152-meter) boom will be used to corral several thousand gallons of the thickest oil on the surface, which will then be towed to a more remote area, set on fire, and allowed to burn for about an hour, the Coast Guard said. Such burns will continue throughout the day if they are working.
It was unclear what would be used to set the oil on fire and how far from shore it would burn. The slick was about 20 miles (32 kilometres) east of the mouth of the Mississippi River.
About 42,000 gallons of oil a day are leaking into the Gulf from the blown-out well where the Deepwater Horizon exploded and sank last week. Eleven workers are missing and presumed dead. The cause of the explosion has not been determined.
Greg Pollock, head of the oil spill division of the Texas General Land Office, which is providing equipment for crews in the Gulf, said he is not aware of a similar burn ever being done off the U.S. coast. The last time crews with his agency used fire booms to burn oil was a 1995 spill on the San Jacinto River.
“When you can get oil ignited, it is an absolutely effective way of getting rid of a huge per centage of the oil,” he said. “I can’t overstate how important it is to get the oil off the surface of the water.”
He said the oil will likely be ignited using jelled gasoline and lit rags soaked in oil. What’s left afterward is something he described as a kind of hardened tar ball that can be removed from the water with nets or skimmers.
“I would say there is little threat to the environment because it won’t coat an animal, and because all the volatiles have been consumed if it gets on a shore it can be simply picked up,” he said.
Authorities also said they expect no impact on sea turtles and marine mammals in the burn area.
A graphic posted by authorities fighting the slick shows it covering an area about 100 miles long and 45 miles (72 kilometres) across at its widest point.
Louisiana State Wildlife and Fisheries Secretary Robert Barham told a legislative committee Wednesday morning that National Oceanographic and Atmospheric Administration projections show a “high probability” oil could reach the Pass a Loutre wildlife management area Friday night, Breton Sound on Saturday and the Chandeleur Islands on Sunday.
The decision to burn some of the oil comes as the Coast Guard and industry cleanup crews run out of other options to get rid of it.
Crews operating submersible robots have been trying without success to activate a shut-off device that would halt the flow of oil on the sea bottom 5,000 feet (1,524 metres) below.
Rig operator BP Plc. says work will begin as early as Thursday to drill a relief well to relieve pressure at the blowout site, but that could take months.
Another option is a dome-like device to cover oil rising to the surface and pump it to container vessels, but that will take two weeks to put in place, BP said.
Winds and currents in the Gulf have helped crews in recent days as they try to contain the leak. The immediate threat to sandy beaches in coastal Alabama and Mississippi has lessened. But the spill has moved steadily toward the mouth of the Mississippi River, home to hundreds of species of wildlife and near some rich oyster grounds.
The cost of disaster continues to rise and could easily top $1 billion.
Industry officials say replacing the Deepwater Horizon, owned by Transocean Ltd. and operated by BP, would cost up to $700 million. BP has said its costs for containing the spill are running at $6 million a day. The company said it will spend $100 million to drill the relief well. The Coast Guard has not yet reported its expenses.