David Lobb, 52, and Barry Purtell, 34, died from injuries sustained in the blast in the cellar of the Rochester Hotel in June 2014.

Coroner Paresa Spanos found the explosion was caused by a cigarette lighter igniting gas that had accumulated in the cellar from a leaking refrigeration compressor.

The pair had offered to help remove the compressor for the licensees, who were vacating the premises.

Read more: Man dead after explosion at hotel

The maintenance of the compressor was a key focus of a 2016 coronial inquest into their deaths, findings of which were released by the Coroners Court recently.

Coroner Spanos found the compressor, which had been known to be leaking refrigerant for several years, had been incorrectly topped up by Mr Purtell in 2013 with a flammable refrigerant intended for use in car air conditioning systems.

Coroner Spanos found on June 15, 2014, the compressor was not accurately labelled to alert anyone to the presence of flammable and non-flammable gases within the compressor.

This, combined with “the cutting and ineffective crimping of the pipes” of the compressor by Mr Purtell, a qualified diesel mechanic, and Mr Lobb, a qualified boiler maker, created a mixture of gases in the cellar which were ignited when one of the two used a cigarette lighter.

“The deaths were preventable, in the sense that proper maintenance of the compressor that dealt definitively with the leak, could have averted the explosion; proper labelling of the compressor as to its actual contents could have averted the explosion, and proper processes being engaged to dismantle and remove the compressor could also have averted the explosion,” Coroner Spanos said.

“Mr Lobb and Mr Purtell died in circumstances of a tragic accident in the course of removing the compressor to help out a friend. While both men were good with their hands and happy to lend a hand, their deaths highlight the dangers of unqualified people doing work that requires qualifications or, at least, a solid understanding of the substances and risks involved.”

Read more: Second man dies from Rochester gas explosion

Coroner Spanos, in her findings, said because the pair were not qualified refrigeration technicians, it would not be appropriate for her to make recommendations about industry practices. 

Mr Purtell sustained fatal blast injuries and died en route to the Alfred Hospital, while Mr Lobb died in hospital almost two weeks later following complications from the chemical burns he sustained, Coroner Spanos found.

The coronial inquest heard from a number of experts, including dangerous goods specialist Peter Vitali.

He said while the hotel’s cellar was not defined as a confined space under the Occupational Health and Safety Act 2004, he felt it would attract requirements of the Dangerous Goods and Storage Regulations, meaning there was an ongoing obligation on the occupier of the premises to adopt suitable risk controls to prevent injury to persons and prevent property damage. 

However Coroner Spanos made no comments or suggestions regarding the hotel licensees in her findings.

Mr Vitali, in giving evidence to the inquest, said: “In life sometimes you’re spared, allowed to make one or two mistakes with dangerous goods, but eventually you combine two or three mistakes in a row and you will have the explosion or the fire. In this case, the first item was the compressor (being) inside the basement (as opposed to outside in the open air). So years go by and someone decides to put flammable gas in it, that’s the second mistake. Thirdly, there are no warning signs, no ventilation, so it just builds up in there when the leak happens and then, in that room, it becomes a chamber where it’s just waiting for an ignition source. After 31 years of being in this industry, they come for free.”

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