London-based oil giant BP, scrambling to clean up one of the largest oil spills in Alaska history and stay out of further trouble with state pollution regulators, now has federal authorities to satisfy as well.

The U.S. Department of Transportation has issued a "corrective action order" to BP to repair a leaky pipeline and improve corrosion inspections in its Prudhoe Bay oil field, the nation's largest. The order, first obtained by the Anchorage Daily News, reveals alarming details about the deteriorated condition of the pipeline, a major oilfield artery that leaked more than 200,000 gallons of oil onto the fragile tundra on Alaska's North Slope.

The pipeline came very close to springing a second leak and maybe more, the federal document says. It says a BP inspection turned up at least six additional corroded spots or other "anomalies" along the 10-mile line, part of a vast web of pipes that drains Prudhoe, funneling crude into the 800-mile trans-Alaska pipeline to the port of Valdez. At one spot, the steel pipeline wall was eaten down to only .04 of an inch, very nearly unleashing more oil onto the tundra. The pipe is 30 years old, installed a year before Prudhoe oil production began in 1977.

The leak, discovered by a passing BP field worker who smelled the snow-covered oil early on the morning of March 2, has triggered a massive cleanup in dangerous, subzero weather, and has cut North Slope oil production by 12%, or nearly 100,000 barrels a day, because the leaky pipeline and more than 200 wells were shut down. The reduced production could last weeks longer.

Stacey Gerard, the Transportation Department's associate administrator for pipeline safety, said the unusual order was issued to BP because continued operation of the pipeline without corrective measures "will be hazardous to life, property and the environment." The order comes in the midst of renewed Congressional fighting over oil exploration in the Arctic National Wildlife Refuge, with supporters insisting that oil companies will be able to drill for oil without damaging the sensitive arctic ecosystem.

The order requires BP to:

Repair corrosion damage to the satisfaction of Transportation Department officials before restarting the pipeline.

Develop a better plan to reduce internal corrosion inside the failed pipe, as well as other major oilfield lines.

Review and improve the pipeline's leak detection system, which failed to warn of the leak.

BP faces potentially millions of dollars in pollution fines from the state. The company also faces a federal civil penalty of up to $100,000 daily if it fails to follow the federal order.

The company had previously expressed surprise at the pipe's leak, but in the wake of the Department of Transportation fix-it order, BP admitted that an earlier inspection of the pipe had revealed numerous weaknesses that were, for unknown reasons, rapidly worsening. The federal order was also noteworthy because BP had previously tried to argue that the federal government had no jurisdiction to oversee the pipe in question.

Company spokesman Daren Beaudo said BP already had planned to take many of the steps the Transportation Department ordered. He added that the company spends aggressively to combat corrosion, a major threat to the aging pipelines of Prudhoe Bay.