The National Transportation Safety Board, which is investigating the cause of the Alaskan oil spill, is concerned that individuals with revoked auto driver's licenses sometimes are allowed to pilot airliners or oil tankers.

Board investigators at the spill site said they were focusing on actions by the ship's captain, Joseph Hazelwood, whose driver's license had been revoked three times in drunken driving incidents while he held the highest-level license granted a ship's captain.Hazelwood had turned over the bridge to his third mate who was not licensed to operate the ship in the Prince William Sound where it ran aground Friday, spilling more than 10 million gallons of crude oil that has spread over 500 square miles.

Ted Lopatkiewicz, a safety board spokesman in Washington, said investigators have not determined whether alcohol contributed to the oil spill but he said they were aware of news reports concerning Hazelwood's alleged record of alcohol abuse.

Lopatkiewicz said he did not know whether investigators had examined Hazelwood's highway driving records in Huntington, N.Y., his hometown.

He said, however, the board had long been concerned with policies that allow airline pilots, ships' captains and other people with major transportation safety responsibilities to remain on the job while not being allowed to drive a car because of alcohol abuse.

Hazelwood's driver's license was revoked in 1984 when he refused to take a breathalyzer test and again when he pleaded guilty to drunken driving near his home. He was convicted of drunken driving in New Hampshire in September and his license remained revoked from that incident, authorities in New York said.

Alaska's public safety commissioner, Art English, said the Coast Guard asked a state trooper to investigate a report that Hazelwood had been drinking before he boarded the ship the night before the accident.

Coast Guard spokesman Randy Peterson said officials would await the results of the NTSB investigation before deciding whether disciplinary action might be taken against Hazelwood or any other officer of the Exxon Valdez.

NTSB investigations normally take about a year to complete, and spokesman Lopatkiewicz said the board would not issue any recommendations of action against an individual before its probe is complete.