Last night BP was accused of serious safety breaches after a fire broke out this month at its Prudhoe Bay operations in Alaska, according to a letter sent to a congressional committee.

Congress is investigating BP’s safety procedures after an important pipeline in Alaska sprang a leak in March 2006 causing a 200,000-gallon oil spill.

While BP admits that repairs have taken place on the back-up system, it insisted last night that damage to the system happened because of the fire.

On August 6 a fire took hold at one of three so-called gathering centres within BP’s Prudhoe Bay operations.

In the letter to Congress, Chuck Hamel, a Prudhoe Bay oil workers’ activist, alleges that BP failed to notice that a key back-up fire and gas emergency system was broken.

Oil from BP wells is pumped into the gathering centre where it is processed to separate the oil from water and gas. Two weeks ago, an oil line within the centre burst, spraying oil. Fumes from the oil were ignited by a turbine’s hot exhaust.

At the time, BP said that the fire suppression system had failed to work when fire broke out because it had been temporarily switched off so that routine monitoring of corrosion could take place.

The system is designed so that once a fire is detected, it dumps the halon gaseous fire suppressant on to the flames, extinguishing the fire.

In the letter to George Miller, the chairman of the House Education and Labour Committee, Mr Hamel alleges that the back-up system was broken. He also claims separately that the back-up system in an adjoining hangar was not functioning.

That back-up system was designed so that should the first system fail it would prevent an explosion. In the letter he says: “BP dodged a catastrophe and its personnel were fortunately spared.”

Mr Hamel alleges that only after the accident did BP become aware that the back-up system did not work and has since instructed maintenance workers to repair it.

Last night BP said: “We place safety uppermost. No one was injured. This is an example of the system working as intended. The fire detection/suppression system was in good order and functioned correctly. The personnel performed properly. The maintenance workers are repairing the louvres near the turbine because they were damaged in the fire.”

Alaskan state officials hit BP last month with new demands for company records to assess the financial and production impact from last year’s oil field shutdown.

Prudhoe Bay, America’s largest oil field, supplies America with a significant amount of its oil.It has suffered two crises in 18 months – in March last year, the bursting of a large pipeline resulted in the biggest oil spill on the North Slope seen to date.

Then in August last year, another pipeline in Prudhoe developed leaks and prompted BP partially to close down the field.

A BP-led group said yesterday that it had cut its 2007 oil output target from its Azeri fields on the Caspian Sea by 22,000 barrels per day to 686,000 for geological reasons.

The group, AIOC, will have to cut production after discovering bigger than expected water and gas yields at some wells, Bill Schrader, the head of the group, said.

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