BATH – Divers battling frigid temperatures searched for the operator of a crane that toppled off a barge and into the Kennebec River on Thursday at Bath Iron Works.

Bath police said the crane fell over around 2 p.m. with an oiler and the operator inside. They did not speculate on what caused the crane to fall.

The oiler was rescued and taken to the hospital.

The crane was not one of the large ones used in the construction of Navy vessels at the shipyard, but one of a dozen smaller cranes used to dredge soil to make room for a dry dock that is being brought in from Portland.

Witnesses said the crane was submerged in the Kennebec. Lt. Joel Merry of the Bath Police Department said the oiler reported hearing something snap just before the crane went down.

“There was a snap, a loud snap. There was movement of the crane … and at that point, it toppled over into the water,” Merry said. “The next thing he knows, he was being rescued.”

Personnel from the Maine Marine Patrol and Maine State Police planned to continue the search through the night.

George Harrigan, who used to operate the crane, said he thought it was unlikely the operator would have survived.

“The operator wouldn’t stand a chance to get out,” he said.

The crane weighs about a half-million pounds, he said.