Three patients have been taken to Calvary Hospital with minor injuries following a small explosion at Bunnings Belconnen.
ACT Ambulance Service intensive care paramedics treated a 15-year-old boy, 23-year-old woman and 87-year-old man at the scene before transporting them to hospital.
ACT Fire & Rescue say a small gas bottle located near a barbecue exploded at about 11:20am.
Firefighters were already in attendance as they were encouraging Canberans to check their smoke alarm batteries.
There was no fire to extinguish after the initial fire ball.
WorkSafe ACT have been requested to investigate.