Police have been called in to investigate a series of explosions in Victoria's Grampians National Park that had threatened the lives of firefighters.
Fire crews had been trying to save farm homes this weekend when a wind change pushed the bushfire north towards the small community of St Helens Plains, causing spot fires and ember attacks.
But firefighters had to pull back on Saturday when a massive explosion blew open a shipping container in the area.
The explosion was followed by a series of smaller, rapid explosions.
Police say a large drum blew up inside the container on the Ross Road property, the impact changing the shape of the container and blowing open the doors.
Fireworks stored inside ignited and were exploding through the open doors.
Detective Sergeant Steve Walker says it's illegal to store fireworks without a permit and any flammable items need to be stored safely.
"CFA volunteers were already putting their lives at risk fighting the fire," he said in a statement.
"For them to be put in further danger because of an incident like this is completely irresponsible."
Arson detectives searched the property on Monday, but no one has been arrested or charged at this time.
No firefighters were injured in the explosion.
The 52,000 hectare Grampians fire, believed to have been sparked by lightning, has destroyed 27 homes but was declared contained on Tuesday.