NEW ORLEANS (AP) -- A fire on a drilling rig that raged after a natural gas well blew out of control in the Gulf of Mexico was no longer burning, officials said Thursday, just hours after confirming gas had stopped flowing from the well.
The well, which had been spewing gas since early Tuesday, became blocked by undersea sand and sediment, essentially snuffing itself out, the Bureau of Safety and Environmental Enforcement said in a news release Thursday morning. Residual gas had continued to feed flames, but the Coast Guard and a spokesman for oil and gas producer Walter Oil & Gas, Brian Kennedy, confirmed the fire was out late Thursday morning.
Experts have said the environmental impact was expected to be limited, even before the well was blocked, and all 44 workers who had been on the rig were safely evacuated. But the well must still be secured to ensure it doesn't start leaking again, and exactly how that would be done was not immediately clear.
Some of the decisions may depend on what type of material plugged the well, said Alex Kolker, an environmental scientist with Tulane University.
"Some materials are certainly going to hold up better than others," Kolker said. "So if it's heavy rock or it's clay, that's going to be less permeable. But if it's sand, and there's a lot of force, then maybe you can bubble the sands out of the way. I think it really depends on the materials."
The rig is called a "jackup rig" because it has four legs extending to the ocean floor to hold it up. Parts of the rig had collapsed as it burned Wednesday, but the structure remained intact.
Because the well involved is a natural gas well, not an oil well, experts said the pollution threats were far less than those posed by some previous accidents.
Federal inspectors said a light sheen was spotted around the rig Wednesday evening but -- like one spotted shortly after the blowout began Tuesday -- it quickly dissipated.
Gas wells often also have oil or other hydrocarbons as well as natural gas. Officials and scientists agree the latest mishap should not be nearly as damaging as the BP oil spill, also in the Gulf of Mexico, that sent crude oil oozing ashore in 2010.
Tuesday's blowout occurred at a drilling rig next to a natural gas platform that wasn't producing gas at the time. The rig was completing a "sidetrack well," which drills into the same well hole under the platform. Such wells are used to remedy an obstruction or to access a different part of the gas reserve.
The cause of the blowout was under investigation, one being overseen by the BSEE. Air and water travel safety restrictions remained in effect in the area until the next steps could be determined.
Associated Press writers Seth Borenstein in Washington and Stacey Plaisance in New Orleans contributed to this report.