"It's grounded and it's being battered by a sizable swell," said U.S. Coast Guard Chief Petty Officer Roger Wetherell.

Conditions at the site were poor, with seas up to 20 feet and winds up to 60 knots, Wetherell said.

"There's thick fog, snow, it's just really bad weather at this time," he said. "That's the concern, that the vessel could be damaged and fuel could leak."

The 286-foot barge broke away from the tug that was pulling it to the port, Foss Maritime said.

Steve Scalzo, Foss Maritime's president and chief executive officer, said the company was taking full responsibility for the salvage and any necessary cleanup.

"Our primary objective is to protect the environment and the safety of all persons involved in the response, especially given the weather conditions on scene," he said in a company statement.

Foss Maritime has mobilized its emergency-response team, salvage crews and equipment, contacted government agencies and notified the California-based International Bird Rescue organization, Scalzo said. A joint command post was being set up to organize the response, he said.

"There's an environment that needs to be protected, and we're going to be here as long as it takes to get the job done," he said.