A Melbourne recycling plant continues to burn but residents evacuated from their homes have been given the all clear to return.
Firefighters expect to be battling the blaze at SKM Recycling in Coolaroo for another three days after the latest fire started on Thursday morning.
Upfield train station and 115 homes in the nearby suburb of Dallas had been evacuated because of toxic smoke created by burning plastic, cardboard and paper.
But people were given the message that it was safe to return home at 5pm on Friday.
Residents are being advised to open doors and windows to flush out any vapours that may have entered the building, the Metropolitan Fire Brigade says.
Four people, including a four-year-old girl, have been hospitalised since the fire broke out.
The plant - which also caught fire in February, June and on Wednesday afternoon - was due to be inspected on Thursday over its fire management practices, Victoria's Environment Protection Authority said.
"The purpose of yesterday's visit was to see how fire risk was being managed at that site and ultimately to give advice," EPA chief executive Nial Finegan told a community meeting on Friday.
"The irony is probably not lost on you of all people as to the timing of that.
"The only thing I can say to that is I wish we'd been able to foresee this quicker and been able to move quicker."
Mother of four Seema Khan lives a few hundred metres away from the factory and was told to leave on Thursday night, but said the evacuation warning should have come earlier.
"Our eyes were burning, the kids were having difficulty breathing," she said.
"From the window we could just see black big plumes of smoke."
Emergency Services Minister James Merlino said the fire was the size of a sports field and reached as high as a factory.
The cause of the blaze is not yet known but the MFB said it was not related to the previous day's fire.
Acting deputy fire chief officer Ken Brown said the fire was particularly difficult to put out because it has penetrated bales of recyclables.
"Whilst we could put the surface part out, the fire's still burning underneath, so we have to get heavy machinery in to pull it apart bit by bit and extinguish it," he said.
SKM Recycling declined to comment because the incident was under investigation.
Melbourne-based Maddens Lawyers flagged a possible class action against the factory's US-based owner-operator, SKM Industries.
