Exxon Corp. agreed Wednesday to pay $900 million to complete the 1989 Exxon Valdez oil spill cleanup off the coast of Alaska and pay a record $100 million criminal fine.

Attorney General Dick Thornburgh said the settlement required "by far the largest single amount ever paid as a result of environmental violation" and signaled the Justice Department's determination to punish polluters.The criminal fine, he said, "sends an important signal that assessments for environmental spoilage cannot simply be answered by paying damages."

The settlement, announced by Thornburgh and Alaska Gov. Walter Hickel, obliges Exxon to reimburse state and federal cleanup efforts from the $900 million fund that it will pay over the next decade.

Exxon Corp. and its shipping subsidiary also agreed to plead guilty to four misdemeanor charges of environmental crimes stemming from the March 24, 1989, spill of 11 million gallons of oil from the tanker Exxon Valdez into Prince William Sound.

The consent decree, which must be approved by a federal judge in Alaska, also includes a clause under which Exxon would pay an additional $100 million for any unforeseen environmental damage.

The criminal fine is 20 times the previous record set for a criminal environmental conviction that was paid by Allied Chemical Corp. in 1976 for spilling chemicals into Virginia's James River, officials said.

Thornburgh acknowledged that by accepting misdemeanor pleas instead of going to trial on the indictment that also charged felony crimes, the Justice Department was avoiding testing novel legal claims during a lengthy criminal trial.

William Reilly, head of the Environmental Protection Agency, said the settlement ensures that "the funds will be available years earlier than any recovery that could have been secured through full litigation."

The settlement will "allow us to turn our full attention finally to the tasks of restoration" in Prince William Sound, Reilly said.

The National Wildlife Federation praised some aspects of the deal but said it couldn't say whether the settlement was adequate for the cleanup until scientific studies of the environmental damage were made public.

But Douglas Wolf, an attorney for the group, said the deal was much better than the $700 million settlement the parties almost reached last year in negotiations that broke down over objections registered by the state of Alaska.

The settlement, reached early Wednesday, was announced a day after a federal judge here lifted an order barring the government from signing an agreement until claims of native Alaskans against Exxon were taken into consideration.

Hickel called the deal "a good settlement for the state of Alaska" as well as good for the federal government, Exxon and the environment.

"It's good to get this behind us," Hickel, a former U.S. interior secretary, told reporters at a news conference.