More than 20 people are in hospital after a carbon monoxide leak at a pork processing plant in Melbourne exposed workers to dangerously high levels of the potentially fatal gas.

Fire Rescue Victoria said it responded to the leak at the plant in Derrimut, in Melbourne’s west, on Monday afternoon, arriving to find 60 people evacuated and some suffering from carbon monoxide exposure.

An Ambulance Victoria spokesperson said 24 people were taken to various hospitals – the Western Hospital in Sunshine and Footscray, the Royal Melbourne Hospital in Parkville and Werribee Mercy Hospital in Werribee. All were in a stable condition.

Fire Rescue Victoria said “firefighters donned breathing apparatus and entered the factory with gas detectors to take readings and assess the situation” on arrival at the Auspork factory on Benn Court.

It said crews found inside the factory that “the carbon monoxide readings inside the building were still dangerously high”.

“Crews ventilated the building until the carbon dioxide in the atmosphere dropped to safe levels,” it said.

The leak reportedly originated from meat preservation machinery.

The incident was declared under control before 2pm local time.

WorkSafe has been notified.

-AAP