Engineers warned BP of Alaskan crisis two years ago

BP has been hit by further troubles in Alaska, after it was forced to shut down even more production at the Prudhoe Bay oilfield and documents emerged that appeared to show the company was warned about the pipeline corrosion problem that has now crippled output.

The latest difficulties will feed into a growing political backlash in the US, where it has been suggested that BP's slogan should be "big problem" rather than its advertising line of "beyond petroleum". A Congressional committee will grill BP's US executives next month over leaks from its Alaskan pipelines.

Joe Barton, the chairman of the House Energy and Commerce Committee, for instance, has said that disruptions caused by the pipeline crisis "are not excusable, particularly in light of substantial evidence that BP's chronic neglect directly contributed to the shutdown". Senator Ted Stevens has said that he feels he was misled for years by BP over its safety and maintenance regime in Alaska, adding that he was "shocked" to learn that 81 per cent of the steel on some portions of pipelines had been eaten away by corrosion.

Yesterday brought yet more bad news on the disruption to the flow of oil to American consumers from Prudhoe Bay, the biggest oilfield in the US. Production at the field, already running at half capacity due to pipeline corrosion, has now been cut by a further 90,000 barrels per day (bpd) for several days due to a technical fault. Output at Prudhoe Bay now stands at just 110,000 bpd, compared with some 400,000 bpd before BP discovered "unexpectedly severe corrosion" in some pipelines there. A spill was first discovered in March and a further leak this month led to the closure of part of the field.

As part of a criminal inquiry into spills, Federal investigators are now reviewing two-year-old documents from an engineering firm that warned of "accelerated" corrosion in its pipeline network - the issue that has now forced the emergency partial shutdown.

Reports prepared in 2004 by a consultant, Coffman Engineers, portray a pipeline system vulnerable to localised corrosion, with large blind spots where problems would be impossible to detect. Coffman's work for BP is being examined by the Environmental Protection Agency in its investigation of BP's maintenance programme.

Don Stears, manager of the corrosion engineering department at Coffman Engineers, said his company predicted BP's current situation. "Our reports were quite accurate as far as the corrosion mechanism that BP needs to address," he said.

Mr Stears added that from assessing the Prudhoe Bay system, Coffman suggested BP needed to take measures to prevent corrosion over its entire pipeline network.

While the reports do include praise of BP, they show that Coffman flagged "accelerated corrosion" as a concern as early as 2004 based on 2003 data from BP. Coffman's reports show, among many things, that BP did not run a standard industry test using a robot called a "smart pig", and that the company did not place "coupons" in proper locations. Coupons are pieces of metal inserted into the pipeline flow, and then inspected to determine if corrosion has occurred.

Daren Beaudo, a spokesman for BP in Anchorage, Alaska, said BP had been surprised by the level of corrosion it had now found at the "transit" sections of the pipeline. The company had previously believed the danger lay in the sections of the pipeline that took oil from the actual field. The transit pipes carry what should be pure crude oil, after sea-water and gases have been removed.

"There is a corrosion mechanism at work here that we don't understand. The [Coffman] reports recognise that corrosion was increasing but we have never denied that... [But] nothing I've seen in Coffman indicated that they pointed at specific problems in the transit lines," Mr Beaudo said. "Coffman was generally very complimentary about our maintenance programme."