CLEARBROOK, Minn. -- Two Superior-based maintenance workers were killed Wednesday when an Enbridge Energy oil pipeline being repaired near this Clearwater County town exploded and burned in a massive fire.

The workers were not identified. The fire might burn for one to three days, officials said.

A dozen or more workers fled the explosion and fire. One was covered in crude oil but not seriously injured, said Jeanine Brand, Clearwater County attorney and public information officer at the scene.

The workers' bodies had been recovered, but their identities were not released, said Kristine Chapin, spokeswoman for the state Department of Public Safety.

Enbridge spokesman Larry Springer confirmed that the two men worked for a maintenance crew based in Superior.

The explosion happened where the Enbridge pipeline crosses Clearwater County Road 3, about a mile south of Clearbrook, about 25 miles northwest of Bemidji.

Matt Lavin lives a half-mile from the site of the explosion.

"I was walking to my deer stand," he said late Wednesday. "I could smell oil, so I looked over there and saw the oil leak shoot up in the air."

He said the oil looked black. "Then it exploded, kind of a whoosh and a boom. The flames went up, I would say, 200 feet in the air."

He was about 600 yards away when the explosion happened.

The Clearwater County Sheriff's Office was contacted at 3:51 p.m. Wednesday about the explosion, Brand said.

Two homes near the site were evacuated because of the fire, which was contained within a few hours.

Several surrounding homes were later evacuated because of concerns that smoke inhalation would injure people, Brand said. The sheriff ordered anyone who could smell smoke in their home to leave, she said.

Late in the night, a contained area of spilled oil about 100 square feet was burning, and officials decided to let it burn off, which might take one to three days, Brand said.

The Red Cross provided food and warm drinks to emergency workers and Enbridge employees monitoring the scene.

Clearwater County Sheriff Mike Erickson blockaded traffic a mile from the scene, allowing only emergency workers and Enbridge employees into the site.

Lavin said he knows many of the people working for Enbridge on the pipeline, which crosses his land on the north side of County Road 3.

For the past week or two, workers using heavy equipment had dug down to the pipeline to repair the leak, Lavin said.

Lavin said he saw the explosion and fire start, although Chapin said Enbridge officials told her there wasn't an explosion, and that leaking fumes started the fire.

Workers had repaired a leak in the buried, 34-inch-diameter pipeline two or three weeks ago with a temporary sleeve, Chapin said. A permanent repair was attempted Wednesday. "It appears one of those fittings may have failed and caused fumes to leak and it caught fire," Chapin said. No cause had been confirmed, she said, but said it was "a big fire," not an explosion.

Enbridge officials posted a news release on the company's Web site stating that pipelines nearby had been shut down after the explosion.

The power to Lavin's home and another nearby residence were turned off for hours. Lavin arranged to have power reconnected to his home late Wednesday.

The pipeline carries crude oil from western Canada into the American Midwest through facilities in Clearbrook and Superior. From Superior it splits off in separate lines to Chicago and Detroit.

News Tribune staff writer Will Aschenmacher contributed to this report.