Emergency services have been called to a fire at Kings Meadows.
Crews got the call to Janet Street around 5.30pm Sunday night, July 23, following reports of an explosion.
Four people were located at the premises.
A 49-year-old man had extensive burns to his face and body and was transported to Launceston General Hospital, and then to Hobart via air ambulance.
The man is in a critical but stable condition.
Two children aged five and nine, as well as a 17-year-old suffered non-life threatening injuries.
Preliminary investigations indicated the fire and explosion was accidental.