An airport chief fire officer killed by a discharging gas cylinder died as the result of an accident, an inquest jury decided today.

Steve Mills was found dead with traumatic head injuries at the Cotswold Airport - the former RAF Red Arrows base at Kemble, near Cirencester, Gloucestershire.

The inquest heard it appeared that he had been hit on the head by the 120kg cylinder of high pressure gas when it discharged violently and span around as he was handling it.

Mr Mills, 45, of Malmesbury, who was fire chief at the Cotswold Airport, died on April 8, 2011.

In their verdict after a four-day inquest at Gloucester Coroner's Court, the jury of 11 said Mr Mills was handling the large, heavy cylinder when due to an accidental discharge he received a traumatic and fatal head injury.

The delivery of the container - in which the cylinder was housed as part of a fire suppression unit - had not been undertaken under the procedures of the Ministry of Defence’s disposal agency, they said.

In addition, the removal of the fire suppression units from the containers had not been undertaken using the manufacturer’s instructions, ruled the jury.

Gloucestershire Assistant Deputy Coroner Tom Osborne said he had thought of sending a letter under Section 43 of the coroner's courts' act to Wiltshire Fire and Rescue Service.

"I was concerned that five senior officers from the service had come before me and not one of them had read the safety notices in the containers about the dangers posed by the fire suppression units," he said.

"But I notice that a senior officer from the service has been here in court, and I assume they will take note of my comments without the need for an official ruling."

In his summing up, Mr Osborne told the jury that the locking pin for the gas cylinder, which would have prevented it discharging, had been found in Mr Mills’ hand.

The inquest heard that as well as being the airport’s fire chief, he was also a retained fireman with the Wiltshire Fire and Rescue Service in his home town.

Mr Osborne said he was well-respected by his colleagues both at the airport and in the county fire service, and a number gave evidence that he was a conscientious hard worker who put safety first in everything he did.

He had arranged for the acquisition of the three large steel containers from the Ministry of Defence at Ashchurch, Gloucestershire, to be used in fire training on part of the airport by the WFRS.

Airport manager Nicholas Howard spoke to Mr Mills on April 7, and was told he would be back on April 8 to clear up piles of redundant cabling and computer parts that a team of his colleagues from the WFRS had stripped out of the containers.

They had been asked to help out by Mr Mills, and he had told them that they could safely take out fire suppression units fitted to the containers, each of which used one of the large cylinders of gas under very high pressure.

He told them there was nothing dangerous about the cylinders but none of the five senior Wiltshire staff had read the danger notice next to the units in the containers.

It warned about the high pressure in the cylinders and that they were extremely hazardous and could discharge violently, causing injury or death.

It also detailed the exact procedures for making the cylinders safe before they were removed, handled or transported.

The inquest also heard from Steve Richards, a former fire extinguisher engineer who is now working as a firefighter at the airport.

Mr Mills had asked him to look at the suppression units because he had a little knowledge of them and he had told him that experts would have to be called in to dispose of them.

He told Mr Mills the cylinders of gas were live, and offered to make them safe by disconnecting them and blanking them off.

But Mr Mills never asked him to carry this out, even though he acknowledged that specialists would have to be called in to remove them.

An expert metallurgist examined the cylinder and said a rapid discharge would have been accompanied by considerable force and would have caused it to spin round violently.

The locking pin found in Mr Mills’ hand had not been in position when the cylinder valve had suffered an impact he said.

But removing the pin would not cause a discharge. A handle also had to be pulled out and he felt it was unlikely this could have happened if the cylinder had fallen and struck the ground.

In a statement after the inquest Wiltshire Fire and Rescue Service expressed sympathy to Mr Mills’ family and friends.

It also said: "Steve was a valued member of the service and is much missed by colleagues.

"Senior officers will continue to support the Health and Safety Executive during its ongoing investigations."

A memorial to Mr Mills has been built by his airport colleagues on the site of the fire training area.