A giant oil slick spread into the Gulf of Alaska Friday, one week after a tanker ran aground, threatening additional fishing communities and a 600-mile stretch of coastline that includes a national park.

Exxon Valdez Capt. Joseph Hazelwood was fired Thursday after tests revealed he was legally drunk hours after the accident. And the FBI said Friday in Washington it is conducting a criminal investigation into the disaster.Hazelwood violated company rules that ban alcohol on its ships, said Exxon Shipping Co. Inc. President Frank Iarossi.

"We are all extremely disappointed and outraged that an officer in such a critical position could have jeopardized his ship, his crew and the environment through such actions," Iarossi said.

The spill, which covers more than 600 square miles, stretched beyond Prince William Sound and threatened fishing communities and more of Alaska's scenic coastline.

Workers at the Kenai Fjords National Park hustled to protect fertile salmon streams along a 600-mile stretch of rugged coastline southwest of the once-pristine sound. The slick could reach the park by this weekend.

"We expect the windward side of our boundary . . . to be slimed," said park superintendent Anne Costellina. "It's our feeling, if it's going to hit us, there's not a lot we can do about it."

The federal government, meanwhile, said it will not take over the spill cleanup. The tanker ran aground on a charted reef March 24, dumping 10.1 million gallons of oil into Prince William Sound.

Coast Guard Commandant Paul Yost, one of three senior officials who surveyed the spill site, said it was "almost unbelievable" that the ship strayed outside a 10-mile wide shipping lane to run aground.

"It's 10 miles wide. Your children could drive a tanker up through it," he said Thursday in Washington.

Hazelwood was the skipper of the 987-foot tanker, but he was not on the bridge when the ship hit Bligh Reef a half-mile outside normal shipping lanes. The ship had just left the Port of Valdez, loaded with crude oil from the trans-Alaska pipeline.

A blood test administered more than nine hours after the accident showed Hazelwood had a blood-alcohol level of 0.061 percent, said William Woody, head of aNational Transportation Safety Board team investigating the spill. The Coast Guard limit for operating a commercial vessel at sea is 0.04 percent, Woody said.

For automobile drivers in Alaska, a blood-alcohol reading of .10 percent is considered legally drunk.

Coast Guard Lt. Ed Wieliczkiewicz said investigators did not know whether the captain consumed alcohol after the boat hit the reef and could have been sober at the time the vessel ran aground. The accident happened shortly after midnight, and the Coast Guard arrived between 2 a.m. and 2:30 a.m.

Iarossi said Hazelwood, 42, was fired in a notice sent to his Huntington, N.Y., home. Exxon and Coast Guard officials said they did not know his whereabouts.

Hazelwood's father, Joseph Hazelwood, said the family had no comment. He refused to say where the captain was.

Maximum criminal penalties for operating a ship while drunk include a $5,000 fine and up to a year in jail, the Coast Guard said. Violators also face the loss of their seaman's license and up to $1,000 in civil penalties.

Coast Guard spokesman Todd Nelson said the agency is waiting for final findings from the federal safety board before proceeding with any criminal charges. Such charges could lead to up to one year in prison and not more than $5,000 in fines. State officials also have started a criminal investigation.

In Washington, FBI spokesman Bill Carter said agents are investigating possible felony violations of the Clean Water Act, which prohibits the "negligent discharge of a pollutant into navigable waters."

The Coast Guard, based on its investigation so far, has begun proceedings to revoke Hazelwood's license, said Guard spokesman Greg Robinson.

Third mate Gregory Cousins, who was piloting the ship without certification when it ran aground, showed no signs of alcohol, nor was there any indication of alcohol in tests administered to helmsman Robert Kagan, Woody said.

Tugboats maneuvered a second empty tanker, the Exxon San Francisco, alongside the grounded Exxon Valdez to unload the remaining 520,000 barrels from the vessel. A barrel is 42 gallons.