Melbourne CBD blanketed by smoke after large factory fire

A factory fire in Melbourne's northern suburbs has left the city blanketed in smoke.

The large fire broke out at the SKM Recycling plant in Coolaroo, 22 kilometers north of the CBD, at around 3:30am local time on Tuesday morning, causing authorities to issue health warnings for the surrounding suburbs.

The center sorts rubbish for local councils and was full of plastic and paper. Around 100 staff were working at the time but all escaped safely, authorities confirmed.

130 fire-fighters attended the scene and successfully bought the fire under control by 8am local time.

Martin Braid, assistant chief of the Metropolitan Fire Brigade (MFB), said the firefight was challenging due to a number of explosions within the premises.

"As you can imagine, it's a recycling plant, so there's lots of paper, lots of plastic, which is highly combustible," Braid tod reporters on Tuesday.

"Then on top of that, there are bulk containers in there with fluid used for hydraulics, and that ignited and created a large fireball that was seen at five o'clock this morning."

Andrew Taylor, a worker at the plant, said there was another fire at the site just last week.

"We had a fire last Monday and that was about eight or nine hours," Taylor said.

"Apparently they had one 10 years ago, the same sort of thing. It burnt the whole place down."

One man was treated at the scene for breathing difficulties caused by the smoke but was given the all clear.

Braid said that factory fires in the outer suburbs were becoming increasingly dangerous as the population increased and spread out.

"These are the pressures of modern society, there's a lot of pressures on urban sprawl and getting into close proximity with manufacturing areas," he said.

"So these are conversations that will be had (by planners) at a local level." Endit