THE DISASTER at the Stockline plastics factory in Glasgow was caused by years of neglect by the company that ran it and by the government watchdog meant to regulate it, according to a report out today. Eight experts from four universities have condemned ICL Plastics and the Health and Safety Executive (HSE) for failing to prevent the gas explosion on May 11, 2004, which killed nine workers and injured 40.

Conditions in the factory were poor, safety rules were broken and corners were cut to save money, the report alleges. But this is denied by ICL, which accuses the report's authors of using "innuendo" to try to discredit and close down the company.

First Minister Alex Salmond has this weekend given his backing to a public inquiry "to prevent a recurrence of this tragedy". The Lord Advocate, Elish Angiolini, is consulting on what type of inquiry to hold and has promised to make a decision before the end of September.

On Tuesday, ICL Plastics and its subsidiary ICL Tech were together fined a total of £400,000 at the high court in Glasgow. The companies had pled guilty to breaching health and safety legislation by failing to protect their workers and by failing to properly assess the risks they were facing.

The explosion which caused the four-storey factory on Hopehill Road in Maryhill to collapse was blamed on a leak of liquified petroleum gas from a corroded underground pipe. The court was told the pipe had been inspected by a student on a holiday job, and would only have cost £405 to replace.

According to one of the report's leading authors, Professor Andy Watterson from Stirling University, the small fine combined with the poor track record of the company and the HSE amounted to a big problem.

"They all point to a system that gives a nod and a wink to the most negligent employers that they can risk lives with virtual impunity," he said.

"The surprise is not that tragedy struck at ICL, but that it didn't happen sooner. Neither HSE nor the firm took the action necessary to remedy problems over 20 years that had a clear potential for catastrophic failure."

Watterson described ICL as a "sick firm" because of allegations that workers had suffered occupational illnesses. Employees had regularly developed "polymer fume fever", he said, and former workers had reported a series of industrial accidents, some of which required hospital treatment.

The multiple deaths and injuries from that terrible day three years ago - which included managers as well as workers - were not the result of an "accident", he argued. They were the inevitable outcome of a "dangerously dysfunctional" health and safety culture "blighted by faint-hearted regulators".

Along with colleagues from Stirling, Strathclyde, York and Liverpool universities, Watterson has written a damning 166-page report on what has become known as the Stockline disaster, after a related company located next door. The report, which was inspired by discussions with ICL workers, is based largely on their testimony.

The report alleges that health and safety regulations were routinely broken at the factory.

Required safety assessments were not carried out, it says, and employees were not consulted, properly trained or provided with the necessary protective clothing.

According to workers, safety standards at the plant were "seriously deficient" and they were "actively discouraged" from raising concerns. The HSE is accused of ignoring workers' warnings about risks.

"Working conditions in the plant were primitive, as management was driven by cost-minimisation and cut corners," said the report's co-author, Professor Phil Taylor from the University of Strathclyde.

"Workers complained of heavy-handedness, arbitrariness and favouritism over questions of pay determination. Reports suggest that management had long been motivated by a hostility to trade unionism and a reluctance to respond to employees' concerns or to listen to their voices."

The ICL disaster was the worst work-related incident in Scotland since the Piper Alpha oil platform fire in 1988, when 167 lives were lost. It was the worst on the Scottish mainland since the 1960s.

The disaster highlights the fact that, over recent years, Scotland has suffered higher rates of death and injury from industrial accidents than England. Between 1996 and 2006 there were 58% more fatalities among workers in Scotland than in the UK as a whole. In addition, since 2001 the death rate has been rising north of the Border but falling down south.

This is officially regarded as the "Scottish anomaly" and has never been satisfactorily explained. Today's report suggests that it could be at least partly due to weaknesses in the inspection regimes for Scottish companies.

At the time of the ICL disaster, the HSE was reported to have only 68 inspectors to police 81,000 workplaces. According to the report, companies that are found guilty of health and safety breaches in Scotland have been fined thousands of pounds less on average than companies in England.

The report accuses the HSE of betraying "staggering naivety" about potential problems raised by workers, and relying on "walk-through" inspections announced in advance. The watchdog was guilty of an "abject failure" to share information with the workforce, it says.

The report concludes: "It is imperative that the First Minister sets up a Committee of Inquiry into the ICL/Stockline explosion with a remit to consider the regulation and management of health and safety in Scotland to establish the broader lessons that we can learn from this tragedy."

ICL Plastics, the holding company for ICL Tech, Stockline and four other companies, was run as a family firm making a wide range of plastic items by Scottish businessman, Campbell Downie, 72. Last week Downie said that he was sorry for the "pain and loss" caused by the disaster.

BUT yesterday his companies issued a statement strongly attacking the new report, pointing out that many of the workers were quoted anonymously. "It appears to be anecdotal and characterised by innuendo," the statement said.

"Whilst we have pled guilty to the criminal indictment we faced and have apologised unreservedly, we refute the suggestion that our working practices were persistently or routinely deficient or that we treat our employees unfairly."

ICL Plastics and ICL Tech said they had suffered "remarkably few" accidents in their 30-year history. According to the high court judge Lord Brodie on Tuesday, they "apparently have a good safety record prior to May 2004, going back to the 1960s."

The companies' statement continued: "It may be there is a desire to discredit the companies, their directors and managers, and loyal employees, without regard of the damage caused to the reputations of the deceased, and pain and suffering of their families, and the injured who returned to work.

"The inference we are entitled to draw is that some commentators would prefer the company to collapse into insolvency with consequent unemployment. We hope the expert group will confirm that this was not their intention."

HSE declined to comment on the report until it had seen it. A joint investigation with Strathclyde Police had led to a successful prosecution, said a spokesman, and HSE would co-operate fully with a public inquiry.

He added: "The verdict of the court recognised the well-established principle in health and safety law that responsibility for the management of workplace risks rests with those who create the hazards."

But the report was backed by local Labour MP Ann McKechin, who described as "very worrying" the allegations about ICL's heath and safety record. "There are also many questions to be asked about HSE's involvement," she said. "This is only the start of the long search for answers as to why such a devastating event could have occurred in the centre of a major city in 21st-century Britain."