The pipeline's owners insist it is safe

The six employees - who have not been named - have written to BP Amoco's Chief Executive, Sir John Browne, warning that "irresponsible operations" at a major oil pipeline are posing an imminent threat to human life and the environment.

But the man in charge of the pipe-line has rejected the claim.

"We're confident that the pipeline is safe," Bob Malone, President of Alyeska Pipeline Service Company, told BBC News Online.

"We know of no situation that exists to make it unsafe."

The allegations - reported in London's Guardian newspaper - centre on the 1280-km (800-mile) Trans-Alaska Pipeline System (Taps).

Exxon Valdez: Alaska still paying the price

The employees say they fear that the 22-year-old pipeline - which carries one million barrels of oil a day - may rupture, or that there might be an explosion at the Valdez oil tanker terminal.

Both installations are run by Alyeska on behalf of BP Amoco, a 50% shareholder. The other co-owners of Alyeska are Exxon and Arco.

"It's not a matter of if it is going to happen, it's when it is going to happen," says one Taps employee quoted by the Guardian.

"It's more dangerous now than it ever was, because Alyeska is being run by spin-doctors," says another.

The letter reportedly contains allegations of

• falsified safety and inspection records
• intimidation of workers and
• "persistent violations of procedures and government regulations"

The employees say they fear a worse disaster than the Exxon Valdez spill a decade ago, which caused terrible and long-lasting environmental damage and cost billions of dollars to clean up.

Sir John Browne: Called on to intervene immediately

Mr Malone of Alyeska Pipeline said he was "disappointed that these individuals don't feel comfortable raising these issues internally. We have a variety of ways for someone to raise a concern in this company."

"If there is an issue that someone knows about that threatens the safety of the pipeline, we want and need to know about it," he told BBC News Online.

"The safety of our people and the Alaska environment are our first priorities," he said.

Not the first allegations

The Guardian allegations are a blow to Sir John Browne, who has "spent two years re-positioning BP as the 'green' oil and gas company".

In 1993, an American Congressional investigation into the pipe-line followed the leak of complaints by so-called whistle-blowers.

Six years later, the Guardian says, safety issues raised by those "imminent threats" have been consistently disregarded.