GRETNA, La.—BP PLC began drilling a relief well Sunday night in hopes of stopping the gush of oil from a leaking well in the Gulf of Mexico.
The company had been waiting until bad weather cleared to begin drilling the well, which it hopes will ease pressure on the oil well that began leaking last month, after the Deepwater Horizon, an oil rig, caught fire and went down about 50 miles off the Louisiana coast.
BP said it plans to begin drilling a second relief well in a couple of weeks. Drilling the wells could take months to complete.
The relief wells are the surest of several options the company is trying to contain the massive oil spill in the Gulf, company officials suggested. To do that, BP must drill another hole—through 13,000 feet of rock a mile under the ocean's floor—that will intercept the leaking well. The company can then pump in cement to try to plug the leaks. The operation is highly complex as the drills must precisely hit the leaking well.
In addition to trying to essentially cap the leaking oil well itself, BP is trying to minimize damage from the oil slick in the water by applying chemical dispersants to break up the oil.
Estimates of the amount of oil leaking from the pipe have been growing, though BP officials said they can't measure the amount. The oil slick from the spill covers thousands of square miles.
The rig caught fire April 20 and went down two days later. Eleven of its 126 crew members are missing and presumed dead. Oil is leaking from three spots in the twisted pipe that once connected the rig to the well. While recent estimates have been that 5,000 barrels a day were leaking, administration officials said Sunday that they feared as much as 100,000 barrels a day could pour into the Gulf if the well infrastructure deteriorates further.
A fact sheet on the company website says BP takes responsibility for the response to the spill after the offshore drilling rig explosion and will pay compensation for "legitimate and objectively verifiable" claims for property damage, personal injury and commercial losses. President Barack Obama and several attorneys general have asked the company to explain what that means.
"We are responsible, not for the accident, but we are responsible for the oil and for dealing with it and cleaning the situation up," Chief Executive Tony Hayward said Monday on ABC's "Good Morning America." He said the equipment that failed and led to the spill belonged to owner Transocean Ltd., not BP, which operated the rig, the Deepwater Horizon.
Guy Cantwell, a Transocean spokesman, responded by reading a statement without elaborating. "We will await all the facts before drawing conclusions and we will not speculate," he said.
A board investigating the explosion and oil leak plans to hold its first public hearing in roughly two weeks. Coast Guard Capt. David Fish, chief of the Washington-based Office of Investigations and Analysis, said the six-member board—three from the Coast Guard and three from the U.S. Minerals and Management Service—will likely meet in the New Orleans area and take testimony from experts and workers who survived the disaster.
"We want to get it public because that's just what our rules are and while everything is fresh in everyone's mind, particularly with the witnesses," he said.
Besides the immediate impact on Gulf industries, shipping along the Mississippi River could soon be limited because the slick was precariously close to a key shipping lane. Ships carrying food, oil, rubber and much more come through the Southwest Pass to enter the vital waterway.
Shipment delays—either because oil-splattered ships need to be cleaned off at sea before docking or because water lanes are shut down for a time—would raise the cost of transporting those goods.
—The Associated Press contributed to this article.