An escalating conflict between Premier Doug Ford's government and four major teachers' unions is headed to the province's labour board as the unions allege Ontaro's school reopening plan violates its own workplace safety laws.

The unions -- which represent 190,000 teachers and education workers -- said Monday morning that they all plan to file complaints after meetings with Ontario government failed to address their concerns last week.

The Association des enseignantes et des enseignants franco-ontariens, the Elementary Teachers' Federation of Ontario, the Ontario English Catholic Teachers' Association and the Ontario Secondary School Teachers' Federation all allege the school reopening plan does not take "every reasonable precaution" to protect workers from COVID-19.

"No worker in the province of Ontario should be expected to sacrifice their health and safety, especially when there are such obvious measures the government could be taking to reduce the risk and prevent potential tragedies," OSSTF president Harvey Bischof said in a statement.

With just weeks to go before classes start, the Ford government has faced increasing pressure over its COVID-19 pandemic back-to-school plan.

The province's strategy will see students in kindergarten through Grade 8 return to school without any reduction in class sizes, though students will spend the day in a single cohort to limit contact with other children.

Most high schoolers will also be in class full-time, though students at some boards across the province will take half their courses online in a bid to curb the spread of the novel coronavirus.

Teachers' unions, school boards, and some parents say the province must lower elementary class sizes and fund the reduction, instead of insisting boards dip into their own reserve funds to lease extra space or hire additional staff to promote physical distancing.

Last week, the teachers' unions had asked the Ministry of Labour to issue a series of workplace orders to set safety standards in schools, setting a Friday deadline for the government.

The unions said the Labour Ministry -- which oversees workplaces in the province -- should order standards which mandate 15 to 20 students per class, to ensure a two-metre distance can be maintained between pupils.

They said an order establishing a maximum cohort of 50 students should be set along with busing standards which take precautions against COVID-19.

"Smaller class sizes would help make schools safer," ETFO president Sam Hammond said in a statement. "Should teachers and education workers not be able to expect at least the same standards and precautionary measures as have been put in place in stores, offices, and other spaces across the province?"

The Ford government has had a rocky relationship with the province's teachers' unions since taking office in 2018.

Earlier this year, the government concluded a contentious round of contract talks with the unions after months of teacher walk outs that led to days-long school closures.

Ford has repeatedly criticized the unions in recent weeks, and on Monday he again appealed to them to work with the province on the return to school. But he also said that the teachers' unions have fought with every Ontario government since the 1990s.

"I think it's ideology, I really do," Ford said. "No matter what we do, it's just not going to be good enough ... they just like to fight. What can I say?"

Labour Minister Monte McNaughton said he could not comment on the complaints, but the government inspectors have been in contact with school boards and staff on the restart.

"My role in this process is as a neutral overseer," he said. "I will not play politics with such an important issue."

Meanwhile, the leader of the Ontario Liberal Party is asking businesses to treat education workers as front-line workers.

Steven Del Duca said retailers and institutions have made life easier for front-line workers during the pandemic.

He said he would like to see teachers, caretakers, bus drivers, principals and support staff have special shopping hours, discounts on products and services, and increased childcare.

Del Duca said they'll soon be on the front lines of recovery and can use the help others are now receiving.

Ontario reported 114 new cases of COVID-19 on Monday and one new death related to the coronavirus. There were also 73 cases newly marked as resolved in the report.

The total number of cases in Ontario is 42,309, which included 2,811 deaths and 38,277 cases marked as resolved.

This article by The Canadian Press was first published Aug. 31, 2020.