Fire raged on an offshore drilling rig in the Gulf of Mexico on Wednesday, a day after a natural gas leak from the well forced the 44-person crew to evacuate.

The Coast Guard said that portions of the rig had “folded” and collapsed and that firefighters were trying to protect the legs of the rig, which was standing in about 150 feet of water. Because it is a natural gas well, the Coast Guard said there would be no impact on shorelines and that a one-mile by 200 foot sheen from gas condensates was “dissipating.”

The rig owner, Hercules Offshore, is the world’s largest shallow water driller with 44 rigs, 19 of which are in the Gulf of Mexico. This rig, about 50 miles offshore, was drilling to a depth of 8,000 feet to begin production from an existing well.

Sources close to the company said workers attempted to close the blowout preventer, but that failed to stem the gas leak. They abandoned the rig around midday Tuesday and fire broke out around 11 p.m. that night.

The Coast Guard said the blowout preventer has now collapsed and there was little chance of plugging the well. Another Hercules rig could arrive by Friday to drill a separate relief well, which would take about 25 days to reach a point in the well where it could cut off the flow of gas.

The Coast Guard also said there was evidence of sand, which was altering the color of the fire. The sand might indicate a collapse of the gas-bearing geological formation at the bottom of the well and might also have caused friction and ignited the fire.

“This blowout reminds us, once again, of the hazards of offshore energy development and the necessity of doing everything we can to reduce the risks to our workers, waters and wildlife,” said Natural Resources Defense Council President Frances Beinecke, who served on the National Commission on the BP Deepwater Horizon Oil Spill and Offshore Drilling.