A work-to-rule campaign by support workers is starting to affect the cleanliness of many Ontario public schools, as litter accumulates on school property.

The Canadian Union of Public Employees, which represents Ontario’s school support workers, has been following “Phase 2” of its ongoing on a work-to-rule campaign since Sept. 29.

As part of the job action, custodians are not sweeping halls, mowing lawns, or frequently emptying garbage cans on school property, leaving lunch leftovers and other garbage to accumulate at schools across the province.

Toronto District School Board spokesperson Ryan Bird told CTV Toronto that the TDSB is “aware” that some hallways are “dirtier” than usual.

“But that is part of the ongoing job action by members of CUPE,” Bird said on Thursday.

After “Phase 2” of the work-to-rule campaign launched on Sept. 29, custodial and maintenance workers were advised not to participate in compost programs or clean pencil sharpeners, whiteboards and chalkboards. They are not to cut the grass unless there's a safety risk, and will only check their email once a day, in the morning. They will also not sweep entrances and hallways or clean the offices of principals and vice-principals.

The union advised all members to ensure student safety above all instructions outlined in the second phase.

The TDSB says that so far, health and safety on school property is being maintained. But, the board acknowledges it is messy inside many schools.

“What we are doing is keeping a constant eye on that, to make sure that it doesn’t reach a level that would call into question students’ safety or health,” Bird said.

The TDSB and other school boards have contingency plans in place in case the mess becomes a safety risk.

Ontario Education Minister Liz Sandals said Thursday that that the “safety and well-being” of students is “paramount.”

“It is disappointing that members of CUPE are engaged in job action that affects our students,” Sandals said. “It is our expectation that school boards are taking the necessary measures to ensure Ontario students are learning in a healthy and safe environment.”

Talks between the union and government continued this week, but Ontario Premier Kathleen Wynne admits she’s frustrated.

“There is a rhythm to these negotiations,” Wynne said. “All we can do is stay at the table and be open to the discussion.”

The union represents early childhood educators, educational assistants, custodians, clerical workers, librarians and other members of Ontario public and Catholic schools.

With a report by CTV Toronto’s Naomi Parness