The extent of the blaze can be seen in video footage shot by ABC News. Photo: ABC
More than 180 firefighters and 66 vehicles are battling a huge factory fire in Derrimut, in Melbourne's west, where hazardous material and unknown toxins continue to burn.
Fire Rescue Victoria (FRV) said there had been a large chemical explosion at the factory on Swann Drive, resulting in one of the biggest fires in recent years.
Deputy Commissioner Michelle Cowling said FRV responded to reports of fire and explosions at the site around 11:20am, with CFA crews also helping to fight the "aggressive fire attack".
"It's still burning, it's not under control yet. We estimate that we're going to be here a couple of days because of the fuel load in this factory," she said.
Several roads around Swann Street have been closed, with nearby factories also evacuated.
Watch the ABC News report here:
Masses of smoke can be seen billowing across the sky from suburbs in Melbourne's west and east.
Near the scene, the ABC saw a charred drum barrel flying into the air from the fire, and landing a few hundred metres away.
The ABC understands the fire is at the site of the ACB Group factory, where a worker died in a chemical explosion last year.
Deputy Commissioner Cowling said multiple 44-gallon drums of chemicals were continuing to explode.
"The warehouse itself is full with multiple types of chemicals, and those drums are being impinged by fire, so they are exploding and therefore they launch into the air and land outside of the fire perimeter," she said.
"So that's why we're encouraging people to stay away."
Warnings have been issued for surrounding suburbs.
Witnesses report 'fireball' explosions
Ravenhall worker Trent Chamberlain told the ABC he could see "thick, thick black smoke" from his office roughly three kilometres away.
"And every few minutes, a large fireball explosion [high into the air]," he said.
"It's still billowing out smoke, quite heavy black smoke, so it's clearly not contained … it looks really bad."
Ambulance Victoria said paramedics had been at the scene since 11:15am.
Victoria Police said there had been no reports of injuries and it was believed everyone inside the factory had been evacuated safely.
- ABC