An airport chief fire officer who died after being struck by a 120kg cylinder of compressed gas had told others a day before his death that it was safe, an inquest jury heard.
It is believed that the cylinder was being handled by fire chief Steve Mills when it discharged violently and struck him on the head.
There were no witnesses to the incident on April 8, 2011, at Cotswold Airport, Kemble, Gloucestershire, and Mr Mills was already dead when he was found by colleagues.
Mr Mills, 45, Malmesbury, who had a son, had worked at the airport for many years.
After a move to a neighbouring airport, he was asked to go back to Kemble to assume a more important role in 2010, Gloucestershire Coroner's Court was told.
Assistant Deputy Coroner Tom Osborne said that as well as running the airport’s fire service, he was also a retained fireman with the Wiltshire Fire and Rescue Service in Malmesbury.
He said Mr Mills had helped Cotswold Airport to acquire a number of steel containers from the Ministry of Defence simply for the cost of transportation.
“These had been used as temporary offices, but the airport intended to use them for other purposes to do with fire training,” he said.
When the containers were delivered, they had to be stripped out of all the remaining office furniture, wiring and redundant computer parts he said.
“This included fire suppression units fitted to each of the containers to help prevent fires,” he said.
The inquest heard that these units used five foot high, 120kg compressed gas cylinders, and the systems were designed to remove all the oxygen inside the containers and stop a fire from spreading.
When the cylinders discharged, Mr Osborne said, it could be quite violent and they were mounted inside a metal cage in the containers.
“There is also a sign in each container warning of the dangers posed by these devices,” he said.
Some of the containers were going to be used by Wiltshire fire service for training, the inquest was told, and a team of officers from the service went to the airport on April 7 to strip them out ready for use in their new role.
Watch manager Paul Keenan, based at Swindon Fire Station, said the team of five met Steve Mills when they arrived, and he showed them the steel containers which had to be cleared out.
“He said to strip everything out of the containers and leave it in the courtyard in front of them,” he said.
“They had pipework, computer parts, shelving and cabling in them, plus the fire suppression units.”
The fire suppression cylinders were bolted to the walls of the containers, he said, and Steve had shown them how to take them out.
“I knew what they were and what they could do but I was not really aware of how dangerous they could be," said Mr Keenan.
“When I first saw the cylinders I didn’t want to touch them, but Steve said they were fine and showed us how to take them off.
"He was calm and knowledgeable and seemed to know it was a safe operation.”
Three cylinders were taken out, he said, and stacked outside against the side of one of the containers.
Cotswold Airport manager and operations director Nicholas Howard told the hearing that no risk assessment had been carried out with regard to the stripping out of the containers once they arrived on site.
He said there was no-one employed there with the expertise to safely remove the fire suppression units and he had assumed that experts would be called in.
He said he would not have expected Wiltshire fire staff to be involved in the stripping out of the containers.
The inquest continues, and is expected to last until Tuesday.