SEATTLE (AP) _ An Exxon tanker carrying more than 22 million gallons of Alaskan crude oil lost power and drifted off the Washington coast for nearly seven hours Wednesday before it was taken in tow.

The 810-foot Exxon Philadelphia had drifted to the northwest, away from land, in an area without reefs and in water 600 feet deep with calm seas and mild winds, Coast Guard Andre Billeaudeaux said.

A tugboat began towing the vessel to Port Angeles for repairs shortly after 3 p.m., Billeaudeaux said. The trip should take about 20 hours.

The single-hulled tanker was about nine miles off Cape Flattery and 12 miles west of the entrance to the Strait of Juan de Fuca when a boiler tube failed about 8:30 a.m., shutting down the propulsion system, said Joe Tucker of Exxon in Valdez, Alaska. The crew of 20 never was in danger, Tucker said.

The incident occurred less than a month after the tanker Exxon Valdez ran aground March 24 near Valdez, dumping 11.2 million gallons of crude oil into Prince William Sound.

The Philadelphia, built in 1970, underwent a shipyard inspection one month ago, Tucker said.

The tanker left the Alaska pipeline terminus at Valdez early Sunday for a non-Exxon refinery in Anacortes, about 65 miles north of Seattle, said Tucker and John Ratterman of Alyeska Pipeline Service Co. in Anchorage.

It carried 532,862 barrels of oil, or 22.38 gallons, according to the Alaska Department of Environmental Conservation in Valdez.

One or two tankers a day make the journey from Valdez to Anacortes.