A Whanganui man who was filling oxygen tanks in a shed behind his house received burns to his arm when a hose burst, starting a fire.
Multiple calls were made to Fire and Emergency NZ when the Mason Tce shed went up in flames at about 10.30am on Saturday.
Explosions were also heard as gas tanks exploded.
The man's father said he was filling an oxygen tank in a shed when a hose burst and shot out onto the compressor and started the fire.
The shed was full of diving gear and wetsuits. When firefighters arrived, it was fully involved.
The man was taken to Whanganui hospital and later flown to Hutt Hospital for treatment.
He suffered burns to his arm but his clothing did not catch fire.
Fire and Emergency had the fire in the shed under control by 11am, Wanoa said.
The shed is in a paved area backed by a concrete block wall and there was little danger of it spreading to another building.
The cause of the fire was investigated by Fenz.