A crane barge holding as much as 8,000 gallons of diesel fuel broke free of its moorings and sank into the Mississippi River early Monday morning in St. James Parish, the U.S. Coast Guard said.

Petty Officer 2nd Class Jonathan Lally, a Coast Guard spokesman, said some pollution was released from the barge but it was contained with boom.

The Coast Guard is working with the barge owner, which was unnamed, and ES&H, an oil spill response company, to determine how much diesel was in the barge’s tank when the vessel sank, the Coast Guard said in a statement.

The barge, which was carrying an excavator crane and a backhoe, went under near mile marker 160 sometime before 5:20 a.m. Monday, the Coast Guard said.

Lally said the barge broke loose from a fleeting area along the river where equipment is on-loaded and off-loaded from barges.

Lally said authorities have determined the sunken barge and equipment are not in the navigable waterway and so do not affect ship traffic.

The Coast Guard said it also is working with McKinney Towing & Salvage for future salvage operations.

The Coast Guard said no injuries were reported in the sinking, the cause of which remains under investigation.