The captain and second mate of the Pathfinder have been relieved of their duties as a result of the tugboat's grounding last week at the same reef as the Exxon Valdez 20 years ago in what remains the nation's worst oil spill.

Crowley Marine operates the tug, which was scouting for ice along Alaska's oil shipping lanes Dec. 23 when it ran aground on Bligh Reef, spilling an estimated 100 gallons of diesel fuel.

Crowley spokesman Jim Butler says the two crew members, whose names have not been released, were relieved of their duties two days later.

The company says it is waiting for the outcome of a Coast Guard investigation to determine any further action.

The company tells Anchorage television station KTUU that once it has a better understanding of what happened, it will decide if the two should be put back on the job.