Two teenagers seriously injured after inhaling gas from LPG barbecue cylinders would have been breathing in fire when the gas exploded, the Fire Service says.
Brendon McLeod, 17, and Jamie Jury, aged 18, were taken to Dunedin Hospital on Monday after the cylinders exploded about 2pm, gutting much of the house on Gordon Road in Mosgiel.
Police say one of the Mosgiel teenagers has burns to three-quarters of his body.
A spokesperson from Dunedin Hospital says he has been flown to Middlemore Hospital in Auckland for more specialised care on Tuesday.
The other teenager remains in a serious condition in Dunedin Hospital's intensive care unit.
Trevor Tilyard, the Fire Service's East Otago assistant area commander, says three LPG cylinders were involved in the explosion - the two the teenagers were 'huffing' from and one in a gas heater nearby.
Mr Tilyard told Radio New Zealand's Checkpoint programme on Tuesday the teenagers were releasing gas into the room and a cylinder connected to the heater is thought to have fallen on its side introducing liquid LPG to the heater which then ignited.
Mr Tilyard said it would have been a huge fire and the pair are lucky to be alive.
Police say a third person was seen leaving the house just before the explosions and is being sought.