An airport company whose health and safety breaches led to the death of its chief fire officer in a freak accident with a gas cylinder was fined £75,000 today.

Dad of one Steven Mills, 45, from Minety, was killed on April 8 2011 when a giant gas cylinder suddenly discharged and hit him on the head as he was moving it at Cotswold Airport - the former RAF Kemble site near Cirencester.

Last month a jury found that the accident followed a failure by airport owners Kemble Air Services to carry out a risk assessment on the cylinders.

Today, at Gloucester Crown Court, Judge William Hart said he accepted that Mr Mills had contributed to his tragic death by the way he tried to move the dangerous cylinder in an 'ad hoc' single-handed way.

But he said he was satisfied that if there had been a proper risk assessment by the company Mr Mills would have complied with it.

He gave the company 15 months to pay the fine after hearing that it is a loss-making firm and the penalty will be a major burden on it.

The judge also awarded the prosecution its full costs of £98,000 against the company after hearing these would be paid by an insurance policy.

The firm has also used money from the policy to set up a trust fund on behalf of Mr Mills' son and it currently stands at £81,000, the court heard.

At the company's trial, when it denied two health and safety breaches, the jury was told the army surplus cylinder had been designed to pump a heavy gas into a sprinkler system if fire broke out in areas where electronic equipment was used.

It was one of many which had been in use in Iraq but had been shipped back to the army storage depot at Ashchurch.

The five foot cylinders and their containers were then offered free of charge to the airport company and had stood disused at Cotswold Airport for several months before the day of the tragedy.

After the jury verdicts last month Mr Mills’ father, Alan, said: "He was a perfectionist in everything he did. His attitude was perfection in anything he undertook to complete.

"No individual person is responsible for the death of my son. It was a series of minor irregularities, leading up to a major event resulting in accident."

Mr Mills, who worked on the family farm in Minety, was also a retained firefighter in Malmesbury as well as being fire chief at the airport.

Mark Harris, for the company, told the court today: "This tragic accident has been a salutary lesson to the company. Two directors are here today and they have taken the matter exceedingly seriously.

"They have taken significant steps to remedy the deficiencies in their processes which led to the commission of the offence. That is a significant mitigating feature. I ask you to give them credit for that."

Passing sentence, Judge William Hart said: "Because Mr Mills was well regarded as a competent and skilled employee the company became blase and assumed that if he got on with the job he would do it safely. There was a 'We'll leave it to Steve' approach.

"If a proper risk assessment had been conducted by the company Steve Mills would have carried it out. He would have complied with it and would never have attempted to carry out this task as he did."

The judge went on: "The company's failure to prepare a suitable and sufficient risk assessment was a significant cause of what happened because the first step towards ensuring health and safety was never taken.

"If it had been it would have regularised his conduct and he would not have been in a position to adopt his own makeshift way of doing what he did.

"The company should have appreciated the likelihood that he would just try get on with the job in an ad hoc way.

"His skills and known abilities were such that the company could not have foreseen that he would undertake the task in the hazardous way he decided to do.

"In acting alone he contributed to his own demise. No-one who knew him could have foreseen he would go about the task in the way he did.

"There is some force in the defendants' argument that with all the company knew of his skills he could not have been expected to endanger his own safety on the day of his death."

The judge said although no-one knew exactly how the accident happened he concluded that Mr Mills was moving the heavy and cumbersome cylinder when he lost control of it.

"The control head and trigger mechanism should have been removed and a protection cap fitted," said the judge.

 "That had not happened although the safety pin was still in place.

"On losing control of it he instinctively tried to regain control but failed. He must have grabbed hold of the safety pin which came out. It was found in his hand after his death.

"The cylinder then discharged. It began to spin uncontrollably and at speed on the ground. It felled him and he suffered fatal head injuries."

After today's hearing, Health and Safety inspector Ian Whittles said: "Kemble Air Services failed to ensure the safety of its employees and others who were carrying out work to decommission the fire suppresion systems.

"The incident could have been prevented if Kemble Air Services had the appopriate oversight and control of the project to develop the training facility. They should have ensured that the work was suitably planned following a full assessment of the risks associated with the work.

"Sadly their failing to suitably assess the risks and implement the necessary controls led to the death of Mr Mills."