Fires burning aboard a pair of barges on Alabama's Mobile River died down early Thursday, hours after a series of explosions loud enough to be heard 20 miles away, a fire spokesman said.
But firefighters have yet to step aboard the barges, which remain secured to their moorings, said Steve Huffman, spokesman for the Mobile Fire-Rescue Department. Temperatures remain too high, he said.
The initial explosion and fire Wednesday night severely burned three workers who were preparing the barges for reloading, Huffman said.
The contractors were in critical condition Thursday at the University of South Alabama Medical Center with severe burns, according to a spokesman. Authorities don't believe any workers are missing.
The first explosion occurred on a barge designed to carry compressed natural gas, according to the U.S. Coast Guard.
It was empty at the time of the blast, but a spark ignited a buildup of natural gas vapors, causing an explosion that caused a second barge to catch fire, CNN affiliate WALA TV reported, citing Coast Guard Lt. Mike Clausen.
At least six explosions rocked the barges, according to authorities.
At the Fort Conde Inn across the river they sounded like "planes above you dropping bombs," general manager Alan Waugh told WALA Wednesday.
"We were up on a second floor balcony and the sky lit up in orange and yellow," he said.
The Coast Guard has closed the shipping channel for one nautical mile around the scene while fire and Coast Guard crews work on a plan to secure the heavily damaged barges.
The barges are moored across the river from the Carnival Triumph, the cruise ship that lost power in February and drifted in the Gulf of Mexico for days before being towed to Mobile for repairs.
At least 500 employees working on the ship were evacuated, Huffman said.
-- CNN's Chuck Johnston, Michael Pearson, Tina Burnside, Dave Alsup, Jessica Jordan, Greg Botelho and Chandler Friedman contributed to this report.
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