The Toronto District School Board (TDSB) says that it has made arrangements for a third-party consultant to review concerns about radiation from a nearby cell phone tower and “make recommendations for next steps” after several staff members at a Toronto high school refused to report for duty earlier this week.

Cynthia Nguyen, the principal of William Lyon Mackenzie Collegiate Institute in North York, advised the school community of the situation on Wednesday morning.

“We are writing to let you know that today, 18 staff members at William Lyon Mackenzie CI exercised their right to begin a work refusal process,” she wrote in a note.

“This process involves the TDSB Occupational Health and Safety discussing concerns with the impacted staff to come to a resolution. In this situation, there are health and safety concerns about possible radiation exposure from a nearby cellphone tower.”

Nguyen said that the school near Sheppard Avenue West and Dufferin Street “did its best to arrange for coverage of classes by administrators” while these concerns were being discussed that day.

On Thursday, TDSB Spokesperson Ryan Bird confirmed that the 18 staff members returned to work following assurances that the matter was being investigated further and that solutions were being sought to address it. He said that the tower in question is "situated close to the school; however, it is not located on TDSB property."

“18 teachers participated in a formal work refusal process as is their right under the Occupational Health and Safety Act. After voicing their concerns several times to the employer, and after delays on the part of the employer, the teachers felt they had no choice but to engage in the process,” Michelle Teixeira, the president of OSSTF Toronto, said in a statement to CP24.com.

The Ontario Ministry of Labour, Immigration, Training and Skills Development, meanwhile, told CP24.com that it has not received any complaints from William Lyon Mackenzie CI about nearby cell phone tower radiation.

Ministry spokesperson Jennifer Rushby urged any worker in Ontario who feels unsafe to report their concerns to the ministry so that they can investigate.

“Our ministry responds to every complaint we receive,” she wrote in an email.

Health Canada, on its website, provides information and safety tips about 5G technology, cell phones, cell phone towers, and antennas.

The federal department said that the radiofrequency EMF emitted by cell phones and cell phone towers is a type of non-ionizing radiation similar to the energy used in AM/FM radio and TV broadcast signals, adding exposure to low levels of it poses “no health risks.”

Tissue heating (the warming of your skin) and nerve stimulation, which can cause a tingling sensation in your skin, were listed as the two main adverse health effects from low-level exposure.

Any further adverse health effects would only occur if there’s a combination of intense, lengthy, and direct radiofrequency EMF exposure, Health Canada said, adding scientific evidence does not point to an increase risk of cancer from exposure to radiofrequency EMF “at the levels permitted by Canadian exposure guidelines.”

“The Canadian radiofrequency safety requirement provides protection against all established health effects,” it said.

“Health Canada continues to monitor all domestic and international scientific evidence on radiofrequency EMF and health. If new scientific evidence were to show that exposure to radiofrequency EMF at levels below the Canadian limits is a health concern, we would take action to protect your health and safety.”