Some townspeople are urging tighter restrictions on visiting seamen after reports that the ship captain involved in the nation's biggest oil spill had a drinking problem.

"They've got to do something to control the people who are driving those tankers," Valdez City Councilor Sally McAdoo said Tuesday.Federal investigators probing Friday's grounding of the tanker Exxon Valdez say they are focusing on the actions of the ship's captain, Joseph Hazelwood.

When the accident occurred, Hazelwood had left the bridge in command of a third mate uncertified to navigate the ice-choked shipping lanes south of Valdez. The ship ran aground on a charted reef and spilled 10.1 million gallons of oil into Prince William Sound.

"I do know that he had a problem with alcohol in the past," said Hazelwood's mother, Margaret, in an interview from her home in Huntington, N.Y. "I know he was rehabilitated. Exxon knows it."

According to Alaska Commissioner of Public Safety Art English, the Coast Guard asked a state trooper to investigate a report that Hazelwood had been drinking before he boarded the ship Thursday night.

Investigators have refused to comment on whether drinking contributed to the tanker accident. They said results of blood tests of Hazelwood and two other crew members would be available later this week.