Investigations are continuing into the cause of a fire in a macadamia oil processing plant at Alstonville in northern New South Wales.
Emergency crews responded to numerous calls to triple-zero on Monday morning about a fire in the town's industrial estate.
A dozen firefighting crews battled the fire fuelled by 100,000 litres of macadamia oil during the day, and up to 20 firefighters stayed at the site overnight to ensure the blaze was under control.
Fire and Rescue NSW duty commander for the Northern Rivers, Gaven Muller, was hopeful the fire would be fully extinguished by Tuesday night, more than 30 hours after it started.
"The fire is still continuing to burn inside in some elevated vats and we also have large piles of husk within the building," he said.
"That's been a little bit problematic for firefighters as we've had significant structural collapse at the rear, and we've got some deep-seated fire there that we can't access or penetrate with our water.
"We are calling in some heavy machinery to assist us to remove some of this material so we can directly attack that fire.
"It will just depend on how we go with our heavy machinery and how accessible these deep-seated pockets of fire are."
Macadamia product shipped around world
Macadamia Oils of Australia's general manager Darren Burton said the company was devastated by the fire.
"It's not the end of the business, factories can be rebuilt. We're well insured, so it just means we've got to sit down and work out how we're going to supply our customers in the short term," he said.
"We ship macadamia product all around the world and we do have quite a bit of stock in our warehouse in Ballina, but we'll just have to decide what the future is for this site."
Mr Burton said the plant had not been pressing oil on Monday and there were no staff on site when the fire broke out.
"We're not sure if there's been an explosion. The worst case scenario is staff getting injured and there's not staff that's been injured and that's fantastic," he said.
He estimated the total loss at $2 million.
Mr Muller said it was crucial that specialised hazardous materials crews were on site.
"With the water that we're putting in and the macadamia oil that's coming out, we have to monitor that run-off and make sure we contain it with booming," he said.
"Ballina Council has assisted us with trucks to actually siphon out the contaminated material and remove it so there's no environmental damage."
The material was being siphoned out of the containment trenches that were dug at the rear and sides of the site.
Atmospheric monitoring was also conducted by authorities.
A warning was put out to people in the area to keep their doors and windows closed, Mr Muller said.
The cause and origin of the fire is still under investigation.
