Five people have been injured - two of them critically - after a backyard heater exploded in the NSW Hunter region.
A man and woman are fighting for life and three others have serious burns after a backyard heater exploded in the NSW Hunter region.
Police believe the diesel heater was being refuelled when it exploded at a Medowie house about 8.30pm on Saturday.
A 50-year-old man and 42-year-old woman were severely burned and airlifted to Royal North Shore Hospital in a critical condition.
Three men, aged 39, 54 and 40, were treated at the scene for serious burns and taken to John Hunter Hospital.
A crime scene has been established, NSW Police said in a statement.