SAN DIEGO (AP) _ The tanker Exxon Valdez, source of the nation's worst oil spill, is headed back to sea after repairs to its shredded hull. But it won't be going back to Alaska and its name will be changed, officials said Friday.

The vessel that spilled nearly 11 million gallons in Alaska's Prince William Sound will be called the Exxon Mediterranean when it returns to duty, due next month, said Exxon Shipping Co. President Gus Elmer.

''Due to declining Alaskan crude oil, the vessel will enter foreign service, most likely loading crude in the Mediterranean or the Middle East. It is consistent with our policy that the vessels be named according to their location,'' Elmer said.

He declined to say that the environmental disaster in Alaska 16 months ago was a major factor in renaming the vessel and changing its use.

''It is strictly an economics decision,'' he said.

Alaska environmental commissioner Dennis Kelso, however, said he believes the name change is due as much to public relations as economics.

''I think the key question is what kind of tankers do we have operating worldwide?'' Kelso said. ''The accident happened here, but it could have happened in Puget Sound or San Francisco Bay - wherever tankers transport crude or its byproducts.

''What broke down here was the system and the tanker was part of it.''

Former Exxon Shipping Co. President Frank Iarossi acknowledged concerns that the ship's association with the disaster may make it unwelcome in Alaskan ports. He said last summer that the tanker might be renamed and possibly put to work elsewhere.

The tanker ran aground on a reef on March 24, 1989, ripping the bottom of its hull open and spilling oil that polluted hundreds of miles of coastline and killed scores of animals.

The 987-foot ship has been undergoing $30 million in repairs since August in a National Steel and Shipbuilding Co. dry dock in San Diego. The company built the ship in 1986.

''The ship's ready. She's going smoothly,'' said National Steel spokesman Fred Hallett. ''We're finishing the painting on it right now and we're doing some work in the machinery room.''

A Coast Guard inspector, Lt. Bill Uberti, said National Steel is scheduled to begin two weeks of trial runs after it is floated out of dry dock on July 20.

''If there's a problem, they'll have to fix it before it can go out into service, but I don't anticipate any problems,'' Uberti said. ''The only damage to the ship was structurally, and that's all been fixed.''

The repair work included installation of 3,000 tons of new, inch-thick steel hull plates on the 30,000-ton tanker.

The ship had a single hull, meaning only one layer of steel stood between its cargo and the open water.

Exxon officials declined to retrofit the ship with a double hull because it was not feasible from an engineering standpoint, Exxon spokeswoman Carrie Chasin said in March.

But Hallett said the ship could have been fitted with a double hull. ''The question is the cost and the time,'' he said.

Kelso said he favors double hulls.

''The fact the Exxon Valdez is being reassigned - I expect it will always be known by its former name and bottom - leads to the question, do we have vessels operating worldwide that have all the protection they should have?'' the Alaskan official said.