SAN DIEGO (AP) _ The Exxon Valdez, responsible for polluting hundreds of miles of Alaskan shoreline, will have an environmentalist at the controls Tuesday when it enters San Diego Bay for repairs.

Capt. Edward J. Silva Jr., the chief San Diego harbor pilot who will steer the damaged tanker to a National Steel and Shipbuilding Co. dock, is a member of the sometimes militant environmental group Greenpeace.

Silva is a critic of many oil company maritime policies, but on Tuesday, his primary focus will be to bring the crippled Valdez safely into port. The ship that caused the nation's worst oil spill was towed from Alaska by tugs, but for greater maneuverability Silva will bring it through the bay under its own power.

Exxon officials said they have no problems with Silva's membership in Greenpeace.

''He's entitled to his opinion,'' said Carrie Chassin, a spokeswoman for Exxon Shipping Co. ''There are people in Exxon who belong to the Sierra Club. I'm sure he'll drive that ship in as professionally as he knows how.''

Silva, a seaman for 42 years, said he comes from a family of mariners - his grandfather and father also were sailors - and his concern for the oceanic environment developed naturally.

He believes the risk of oil spills has increased with crew reductions in recent years on the more sophisticated tankers.

''You can build the strongest ship in the world but if you don't do the job right and you have an accident, you're going to have an oil spill, period,'' Silva said. ''Where you're going to stop it is by making sure the people operating these ships are operating them safely and have enough people to do the job.''

The former captain of the Valdez has been accused of drinking on the job.

Silva also said he believes the Valdez accident would never have occurred if a qualified pilot had been aboard to guide the ship through the sound. The pilot who had helped guide the ship through Prince William Sound had left it a few miles before the accident occurred March 24, as regulations allowed.

''I may be biased, but there should have been an Alaskan pilot on board,'' Silva said. ''They're more familiar with the area. I guarantee you if there had been one on, it wouldn't have happened.''

Silva said the Coast Guard will take him out to the Valdez by helicopter Monday so he can familiarize himself with the ship and its handling.

''Given that the ship is damaged, I'm not really sure how it's going to handle,'' he said. ''Suppose there is a jagged piece of steel down there someplace I don't know about? It could have an effect on how the ship steers.''

''I'm doing it just to be absolutely certain in my own mind ... that the ship can handle OK,'' he said.

''There's no one more interested in trying to keep this area clean than I am, believe me.''