A COMPANY responsible for the biggest poisonous gas leak in the North West since 1990 wrongly told residents that they had not been in any danger, a court heard.

Three people were injured, more than 400 people called police and 2,000 were told to stay indoors after the "disaster" at Nipa Laboratories' factory in Oswaldtwistle, Burnley Crown Court was told.

Nipa has admitted two health and safety offences and four breaches of its operating licence following the leak on the night of May 6, 1998, when more than four tons of sulphur dioxide and hydrogen chloride escaped from a gas neutralising machine.

The next day residents received letters addressed "Dear Neighbour" which claimed the gases were not dangerous - but by then the company knew that was not true, said Nigel Lawrence, prosecuting for the Health and Safety Executive and the Environment Agency. The company has blamed an "idiotic" employee - who has since been sacked - for causing the leak by using a metal bar to override a safety button. But it admitted that a second failsafe mechanism which would have prevented the leak did not work because it had been wrongly installed.

Mr Lawrence said the gas leak was the worst of its kind in the North West since Environment Agency monitoring began in 1990, and asked that Nipa pay £52,000 in prosecution costs.

The court heard that process operator Paul Rowe - who had no formal training - had used a metal bar to override a safety button which controlled the flow of thionyl chloride, a highly reactive liquid used to make an industrial preservative. As a result, a toxic gas cloud drifted 700 metres towards Stanhill, said Mr Lawrence. Andrew Moran QC, defending, said Mr Rowe - who he called "devious" and "obstructive" - lied to his boss about what he had done. Mr Moran said that if Mr Rowe had told the truth, the gas leak might have been prevented. "Only an idiot would jam the safety button with a bar and wander off doing something else," he said.

The court heard that senior production manager Philip Arnold knew the safety button had been overridden on another occasion, but had not told his superiors.

Mr Moran said workers realised there was a problem around the time the leak started, but could not work out what was wrong because Mr Rowe had lied and tampered with equipment to cover his own tracks.

Fellow worker Stanley Marshall was injured when he tried to resolve the problem.

Another worker, Toni Astley put on a breathing suit as he tried to solve the problem but was overcome by fumes and had to be pulled out by other employees. Susan Walmsley, of Stanhill Lane, Oswaldtwistle, was taken to Blackburn Royal Infirmary with breathing difficulties and blisters to her face after being affected by the leak.

Mr Moran described the incident as a "disaster" but said the company had since installed new safety measures, was committed to environmental safety and was determined to ensure nothing similar happened again.

North West Water offered no evidence against Nipa at Blackburn magistrates yesterday on pollution charges relating to the River Calder, dating back to 1995.

North West Water successfully applied for costs, which it said marked the fact it was not wrong to bring the prosecution. Nipa had denied that it had killed fish in the river. The matter has now been withdrawn.

(Proceeding)

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