Thomas Foods International fire, Murray Bridge | VIDEO, PHOTOS

About 20 were on the scene early on, but a Metropolitan Fire Service spokeswoman said reinforcements had been called for as the threat continued.

“While it’s contained there have been flare-ups which we’re expecting to continue this morning,” she said.

“It’s in the basement area of the facility at the moment.”

She confirmed that most of the meat works had been saved, but that the area impacted by the fire had taken significant damage at a likely cost of tens of millions of dollars.

A hundred firefighters from 13 MFS and 11 Country Fire Service units were involved in the fire fight at its peak last night.

SA Police officers controlled traffic and kept the public at a safe distance, paramedics from the SA Ambulance Service monitored firefighters’ health throughout the night, and the Salvation Army delivered meals to weary personnel.

Investigators will inspect the scene and speak with witnesses later today, once the danger from the fire has passed.

In a new warning message issued just after 7am, the MFS advised residents – especially those with respiratory issues – to close their doors and windows until the smoke passed.

Murray Bridge's biggest employer has had one of its darkest days.

Thomas Foods International's meat works were heavily damaged by fire tonight, January 3.

All employees were safely and quickly evacuated, but the factory's largest building was destroyed at a cost which will likely run into the millions of dollars.

The company issued a statement just after 10pm, saying the cause of the fire and extent of the damage were yet to be determined.

"While this is being assessed, the company is making alternative processing arrangements to meet our customer requirements," it said.

The Murray Bridge abattoir is TFI's largest, but it has smaller facilities at Lobethal; Tamworth, New South Wales; and Wallangarra, Queensland.

The local facility’s production lines will be closed for Thursday at least, and only senior managers and office staff will be required on site; the company will contact other employees in the morning.

SA Police advised that the fire had been contained to the one building, but that extensive damage had been caused.

Investigators will visit the premises in the morning.

The Metropolitan Fire Service (MFS) advised that the threat to public safety from the fire had passed by 10.30pm, but police suggested keeping doors and windows closed to shut out any smoke.

At least 80 MFS and Country Fire Service firefighters from 25 units are estimated to have been involved in the fight.

They were still monitoring the scene at 10.30pm, and SA Police said they would remain throughout the night.

Lagoon and Nilpena Roads also remained closed.

It is not yet clear what impact the fire will have on the company's hundreds of employees, a mix of locals and migrants on skilled work visas.

TFI is Australia's largest family-owned meat processing company, with an annual revenue in excess of $1 billion.

Did you experience the evacuation of the meat works?

Do you know which buildings were damaged in the fire?

Did you take any photos or videos at the scene?

Email peri.strathearn@fairfaxmedia.com.au or message The Standard’s Facebook page.

Firefighters are tackling a significant blaze at Thomas Foods International, Murray Bridge.

Smoke and flames are pouring out of the largest building at the meat works, and dozens of MFS and CFS officers are combating them as police ward off a growing crowd of onlookers.

The fire has reached a fifth alarm, which an MFS spokeswoman said indicated it was “quite significant”.

The MFS has issued a warning message for residents of Northern Heights and surrounding suburbs, advising that smoke is drifting across the area – as almost anyone in that area would have noticed.

The MFS will issue further advice by 11pm.

For up-to-the minute information, visit www.mfs.sa.gov.au.