New Brunswick's chief medical officer of health was working on a study of the controversial herbicide glyphosate when she was put on leave, CBC News has learned.

Dr. Eilish Cleary wrote to a Kent County resident in August that her office would be "developing a plan to further explore" the herbicide, which is used in New Brunswick by forestry company J.D. Irving Ltd. and by NB Power.

This is not a situation where I requested a personal leave. - Eilish Cleary , chief medical officer of health

​Cleary confirmed in an email to CBC News Wednesday that "This is not a situation where I requested a personal leave."

She said she was not allowed to discuss the reasons for the leave.

"I was surprised and upset when it happened. The whole situation has caused me significant stress and anxiety. And not being able to talk about it makes it worse."

WHO deems glyphosate probably carcinogenic

The International Agency for Research on Cancer, a branch of the World Health Organization, deemed glyphosate "probably carcinogenic to humans" earlier this year.

In a letter to Bass River resident Ann Pohl in August, Cleary said she and her staff concurred with the IARC finding and would look into it.

Pohl provided a copy of the letter to CBC News.

Health Canada said earlier this year that the federal Pesticide Management Regulatory Agency would re-evaluate glyphosate, but pending that review, it wasn't considered harmful to human health.

I'm concerned there might be some corporate or political pressure put on [ Cleary ] for her to stand aside. - Ann Pohl , Bass River resident

If Health Canada found action was needed, Cleary wrote in her August letter, "please be assured that I will take proactive action to ensure that public health in New Brunswick is protected."

Pohl, who is a member of the Council of Canadians, says Cleary responded quickly when she first contacted her about glyphosate. "She was very interested in the issue.

"I'm concerned there might be some corporate or political pressure put on [Cleary] for her to stand aside."

Pohl says Dr. Jennifer Russell, the acting chief medical officer of health, told her on Nov. 9 the glyphosate study was still going ahead, and the office's action plan would be complete before the 2016 spraying season.

Health minister says 'personnel matter'

Health Minister Victor Boudreau told reporters Cleary's leave "is a personnel matter. It's not something we can comment about. It has nothing to do with the office per se, or the independence of the office. It's an HR issue and I won't comment anymore."

In 2012, Cleary wrote a report on what she considered the "social and community health risks" of shale gas development, a report the then-Progressive Conservative government considered keeping secret.

The PCs eventually allowed it to be released.

"I think I have had to re-affirm my right and my ability to speak," Cleary later said about the episode.

Pohl says she admired Cleary's work on shale gas "and we were really hoping she'd do the same thing with the glyphosate spraying issue."

'She's an action hero for us'

"She's an action hero for us in New Brunswick," Pohl says.

"We have so many of these environmental health issues and so many things that we need to be thinking about."

The Liberals, who accused the PCs of trying to "muzzle" Cleary on shale gas, promised in their 2014 election platform to "ensuring the independence of the medical officers of health."

The platform also said any decision on fracking would "follow recommendations of the Chief Medical Officer of Health."