The National Transportation Safety Board yesterday spread the blame for the wreck of the Exxon Valdez among an alcohol-impaired captain, a fatigued and overworked third mate, inadequate Coast Guard vessel controls, inadequate Exxon crew policies and ineffective pilot services to escort the ship beyond a dangerous reef.

The board brushed aside claims by attorneys for former captain Joseph Hazelwood that blood samples were mishandled and do not provide proof that he was drunk on the night that the supertanker ran aground at Bligh Reef, resulting in the country's worst tanker oil spill.

Board Chairman James Kolstad said that errors in the "chain of evidence" cited by Hazelwood's attorneys were minor technical problems, and "the fact is, the samples were not tampered with."

During a daylong hearing, board staff members said the evidence is clear that Hazelwood's blood-alcohol content at the time of the accident was between 0.2 and 0.25 percent, more than twice the limit for a drunken driving conviction. Chief investigator William Woody said an analysis of alcohol tests and eyewitness accounts of what Hazelwood drank on shore indicates that the captain was drinking even as the ship left the harbor.

"I'm suggesting he drank on board, from those calculations," Woody said.

Thomas M. Russo, one of Hazelwood's attorneys, called the board hearing "ridiculous," adding, "All I know is the blood-alcohol {test} was invalid."

Russo said last week that a form from ChemWest Analytical Laboratories, dated four days after the accident, indicated they received three red-stoppered 10-milliliter tubes of blood, not two gray-stoppered and one red-stoppered tube of different sizes as reported by the Coast Guard technician who took the samples.

Board staff members said yesterday, however, that the technician later acknowledged he made a mistake on the size of the tubes, and that a clerk at the lab mistakenly assumed all the samples had red stoppers because the two gray stoppers were covered by tape. Sealing tape with the initials of the technician were intact, and one of the gray-stoppered tubes is still unopened with the seal intact, they said.

Hazelwood had left the bridge more than a half hour before the ship ran aground shortly after midnight, and the ship was being handled by the third mate, who the board described as fatigued after arising early and working all day as the ship was being loaded at Valdez. The mate also did not have the proper license for handling a ship alone in those waters.

The board said that it could not account for why the ship did not begin executing a turn until about six minutes after the mate said he ordered the turn away from the reef. But the safety board staff discounted reports that the automatic pilot was on and prevented the turn. They said it was likely that the mate simply got lost.

The staff also said that the mate could have still saved the ship at the last minute with a hard right turn, but he ordered only a gradual turn, as if he did not know the reef was dead ahead.

The board said that one reason for the mate's fatigue was the failure of Exxon Shipping to provide enough crew members on the ship.

In addition, the Coast Guard's Vessel Traffic Service was inadequate, the board said, with inadequate equipment and personnel and defficient management oversight. Although the Exxon Valdez was the only ship moving in the area at the time, the Coast Guard radar lost track of it.

The board said that local pilots should have remained aboard tankers such as the Exxon Valdez until after they were clear of the reef, a practice that was instituted following the accident.