An Edmonton teacher whose suspension has stirred a debate over whether students should be given zeros when they don't do their work says he is on the brink of losing his job – and even his teaching certificate.

Lynden Dorval has been a physics teacher for 35 years but his refusal to back down from a fight over a school policy that bars teachers from handing out zeros could spell the end of this career.

He says he’s already received a letter from the principal of Ross Sheppard High School recommending his dismissal.

“I have been told that termination often results in withdrawal of teaching certificate, which means I may not be able to teach anywhere,” Dorval told CTV’s Canada AM from Edmonton Friday.

Dorval, 61, was suspended in June after a number of incidents in which he assigned students zeros for failing to complete assignments.

The zeros were not meant to be final grades, Dorval has said; just indicators of the grades they could receive if they didn’t complete assignments, he told CTV News in June.

But the school says Dorval deliberately flouted a clear policy against zeros that was introduced at Ross Sheppard High School almost two years ago.

Policy proponents say zeros are counterproductive because they don't reflect what a student knows about a subject. They say unfinished work should be treated as a behavioural problem, not an academic one.

But Dorval, who’s been dubbed the "Hero of Zero," says that grading zeros helps prepare students for the real world. He says he doesn’t believe the argument that research shows that zeros are counterproductive.

“There’s actually no research that backs what they’re doing; it’s simply a philosophy. I believe it damages students to allow them to just get away with not doing any work. They say that giving out zeros damages their esteem and makes them give up. But in my experience, that’s not true at all,” he said.

Dorval says he knew when he was handing out the zeros that he was violating the rules, but he says he was left with no other way to voice his opposition.

“There wasn’t any other means. We weren’t allowed to discuss it at staff meetings; it came down from administration. And to me, that’s not the way things are supposed to be,” he says.

He says his own teachers’ association has a policy that decisions about student evaluation should be made by teachers.

“I spent my while career with the understanding I was the one to make decisions about how to evaluate my students,” he says.

Dorval’s principal has requested Dorval’s termination for his “obvious neglect of duty as a professional teacher, his repeated insubordination and his continued refusal to obey lawful orders.”

The Edmonton Public Schools board had an emergency meeting in June and decided to re-evaluate the policy. But in the meantime, Dorval faces a hearing with the school superintendent on September 10 about the request for termination.

“So there’s still a chance that something might change but it’s likely going to be too late for me,” Dorval says.