Oil giant BP has denied misleading a U.S. environmental regulator about having installed safety equipment at its Texas City refinery that investigators believe would have reduced the likelihood of a fatal explosion last year.

We did not mislead the Texas Commission on Environmental Quality, BP spokeswoman Wendy Silcock said on Saturday.

Earlier, the Financial Times newspaper reported that documents filed in a Texas court showed BP had said in a 2003 emissions permit application that it had a flare system for burning off flammable vapours emitted by its refinery.

In fact BP had a simple vent stack for dispersing vapour into the air and the stack was only designed to handle small amounts of vapour.

Improper operation of the unit which fed the stack led to a large emission of vapour in March 2005. This was ignited by a idling truck nearby, causing an explosion which killed 15 people and injured 170.

The U.S. Chemical Safety and Hazard Investigation Board, which is investigating the explosion, has called for doing away with vent stacks.

Silcock said BP did apply for an emissions permit in 2003 but could not confirm or deny whether the application claimed BP had installed the flare system.

BP has paid out hundred of millions of dollars in settlements to relatives of those killed and survivors of the explosion. However, some relatives and survivors are going forward with wrongful death lawsuits.

The Occupational Health and Safety Administration fined BP $21.3 million (11 million pounds) for 300 wilful violations of health and safety standards at the refinery and the U.S. Environmental Protection Agency also recommended an investigation of possible criminal violations of environmental law.

BP is also under pressure from senior U.S. lawmakers for its management of oil pipelines in Alaska.

BP was forced to halve production at the U.S.'s largest oil field at Prudhoe Bay, Alaska, after severe corrosion was detected in pipelines. BP accepted its maintenance regime had been inadequate, despite earlier rejections of criticisms.