A southern Ontario high school teacher allegedly tried to scare his students into not getting vaccinated for polio, diphtheria and other diseases, a discipline panel of the Ontario College of Teachers heard on Tuesday.

Timothy Sullivan, a science teacher at the Grand Erie District School Board, is accused of professional misconduct relating to a 2015 school vaccine clinic where, according to the allegations, he "told students they could die as a result of the vaccination."

"His behaviour was confrontational and intimidating," said Christine Wadsworth, a lawyer for the college, in her opening remarks at the discipline hearing.

The college alleges that on March 9, 2015, Sullivan disrupted the clinic at the high school where he teaches.

The name of school is under a publication ban in order to protect the identities of students.

Nurse felt threatened

Angela Swick, a registered nurse with the Haldimand-Norfolk Health Unit, told the hearing that Sullivan came into the school cafeteria where the clinic was taking place on three separate occasions.

"I remember feeling threatened," she said.

Swick told the hearing that Sullivan requested the product monographs — inserts that contain detailed medical information — for each of the vaccines.

In her 20 years of experience administering vaccinations at schools, Swick said, a teacher had never before asked for this material.

Later during the clinic, with students present, Swick said, Sullivan asked them if they knew what was in the vaccines and "shouted at them not to get it."

'I'm not an anti-vaxxer. I'm pro informed consent,' Sullivan told reporters at the hearing in Toronto on Tuesday. (Trevor Dunn/CBC)

Swick informed the school's principal, who attended the clinic and locked the doors Sullivan was using to access the clinic. At one point, she said, another teacher was brought in to "keep an eye out for Mr. Sullivan."

After this, Swick said, she contemplated shutting down the clinic.

"We were concerned it was an unsafe environment."

Principal heard complaints

The school principal at the time, Brian Quistberg, told the hearing that multiple students informed him Sullivan was at the clinic attempting to discourage students from getting vaccinated.

Quistberg also told the hearing that, prior to the clinic, students and parents had expressed concerns to him about Sullivan's repeated discussion about vaccines in his classroom.

Quistberg said he had notified the school board after an incident earlier in 2015 involving a student presentation about vaccines.

An email Quistberg received from the student's parent, presented at the hearing, said that Sullivan "interjected early and often" in the presentation and "argued the information was incorrect."

The email said Sullivan's "anger level escalated to the point that [the student] left the classroom in tears."

'Pro informed consent'

Sullivan, who said he can't afford a lawyer and is representing himself at the hearing, is focusing his defence on the "informed consent" required for health officials to give vaccines.

"I'm not an anti-vaxxer. I'm pro informed consent," Sullivan told reporters at the hearing.

"They make it sound like I was running around saying this will kill you. What I was doing was referring them to a product label," Sullivan said in his opening remarks.

In his cross-examination, Sullivan went through a long list of rare side-effects, including anorexia and convulsions, contained in a vaccine's product monograph, asking Swick if she informed each student of them.

"We warn them of the most common side-effects," Swick said.

"But not the most serious?" Sullivan asked.

"It's so rare, that we don't," Swick answered.

Sullivan was suspended for one day without pay by the Grand Erie District School Board.

If found guilty by the discipline panel, Sullivan could have his teaching certificate revoked or be fined up to $5,000, among other potential penalties.

The hearing is scheduled to last two days.