Employees at the Toronto South Detention Centre are involved in a work refusal effort after an apparent attack on officers by inmates over the weekend.

According to Ontario Public Service Union president Warren “Smokey” Thomas, eight correctional officers were injured in the attack on Saturday night.

Two correctional officers told CP24 that inmates pretended there was a fight unfolding in a common area. When two correctional officers went in to help, they were instead attacked by more than 30 inmates.

Thomas said the inmates “turned on them.”

“They then called for reinforcements and they were assaulted as well,” he told CTV News Toronto on Monday. “It appears to be planned out by the inmates.”

The officers tried to run but were chased while items were thrown at them. Both officers are said to have suffered concussions.

There was no official word on the severity of injuries the other staff members suffered, however Thomas said no one sustained life-threatening injuries.

“Some of them have injuries that I think will keep them off work, at least for a while,” he said.

The centre has been on “lockdown” since staff walked off the job.

Thomas said the officers want the facility to undergo an inspection by the ministry to address what they claim are health and safety concerns. He claims violent incidents like the one that unfolded Saturday are a “fairly regular occurrence” at that location and across the province.

“The employer absolutely refused to address the incident on Saturday night. There have been no consequences for the inmates who launched the attack, they’ve not been moved to another institution, which should be done,” he said.

“What they want here is the inmates dealt with, they want the classification system – how they “classify inmate acuity and dangerousness – they want that put into place. They tell me today that this institution had a danger level, like an assessment, done in 2013 before it opened, but there’s never been one done since.”

Toronto police said “a majority of the workers” at the detention centre are involved in the work refusal and may impact court proceedings.

Police said they were notified of the work stoppage at around 6:30 a.m.

It is not clear when normal operations at the facility will resume.