WASHINGTON (AFP) – BP is to continue pumping oil from part of a giant field in Alaska, where a corroded pipeline sprang a leak last week, and aimed to raise output to 200,000 barrels per day.

BP America chairman Bob Malone said the British energy giant had doubled its spot inspections of a five-mile (eight-kilometre) segment of the pipeline serving the western part of Prudhoe Bay, America’s largest oil field.

“The results have been encouraging and have increased our confidence in the operational integrity of this pipeline,” he said in a statement.

“With greatly enhanced surveillance and response capability, I am confident we can continue to safely operate the line.”

When operating at full capacity, Prudhoe Bay pumps out 400,000 barrels of oil a day — 8.0 percent of total US daily output.

After the pipeline leak was discovered a week ago, BP started scrambling to shut down the entire field while it upgraded ageing infrastructure dating from the late 1970s.

Oil prices shot up Monday on news of the BP leak, with Brent crude striking a fresh record high of 78.64 dollars per barrel.

But crude futures have since retreated, helped by signs that BP’s problems in Alaska may not be as bad as initially feared.

The company late Thursday won a green light from the US government to continue operations from the western part of Prudhoe Bay, provided it followed stringent checks mandated by the Department of Transportation.

BP said current production from the stricken field was now 150,000 barrels per day, including natural gas liquids.

That was expected to increase to 200,000 barrels per day after completion of a planned maintenance shutdown on an operating centre, it said.

The company said it would complete the installation of 16 miles (26 kilometres) of new oil transit line at Prudhoe Bay by early next year, with a review to then reopening the eastern half.

The decision to continue production from the western half was taken after more than 1,400 ultrasonic inspections of the five-mile section of pipeline, BP said.

The British firm said it would now start round-the-clock visual and infra-red surveillance of the line.

The surveillance effort will include daily over-flights using infra-red cameras, as well as the use of hand-held infra-red cameras on the ground.

Two vehicles equipped with equipment to clear up any spills and carrying observers with infra-red leak detection kits will patrol the line 24 hours a day, while engineers will visually inspect the line 10 times a day, BP said.

Steve Marshall, the president of BP Exploration Alaska, thanked state and federal personnel “for giving this effort their complete and undivided attention”.

“I also want to thank the hundreds of men and women who have been inspecting pipe, studying the data, developing plans for enhanced surveillance of the pipeline, evaluating options and doing it all safely,” he said.

The incident has raised fresh questions about BP’s safety record in the United States, after a major oil spill in the same region of Alaska in March and a huge blast at its Texas City refinery last year that killed 15 workers.

The company was forced to deny reported claims by a whistleblower that it had ignored corrosion problems at the Alaskan pipeline for years. But some have accused BP of acting with excessive zeal now.

Alaska Governor Frank Murkowski, noting his state is losing about 6.4 million dollars in daily revenues due to the shutdown, had queried the need to cease all operations from Prudhoe Bay.