Is pollution from industry causing the neurological disease ALS in New Brunswick? [video]

Long-term exposure to the industrial pollutant sulfur dioxide is “significantly associated” to the neurological disease ALS in New Brunswick, according to new research published in the peer-reviewed journal Environmental Research.

ALS, also known as Lou Gehrig’s disease, causes a loss of muscle control that worsens over time, eventually affecting patients’ ability to move, speak, eat, and breathe.

The disease is fatal and there is no known cure. Between 2,500 and 3,000 people have the disease in Canada — and most die within three to five years after the onset of symptoms.

The new study doesn’t prove that sulfur dioxide, or SO₂, actually causes ALS. However, it shows that even a slight increase in exposure increases the odds in a “very drastic” way, according to Daniel Saucier, a postdoctoral fellow at the Centre de formation médicale du Nouveau-Brunswick.

“While we can’t say it’s solely responsible…  it is a key piece of the puzzle,” he told a legislative committee reviewing the Clean Air Act in September.

Saucier said there is “no safe level of pollution” and called for continuous improvements in air quality.

He made the comments as the provincial government prepares to update air pollution rules for the first time since 1997.

“These standards need to be continuously updated, not on an almost 30-year basis,” he told the Standing Committee on Climate Change and Environmental Stewardship.

The research looked at 304 cases of patients diagnosed with ALS from January 2003 to February 2021, comparing them with a control group of 1,207 people of the same age and sex.

The study identified the home addresses of patients before the onset of ALS — drilling down to the postal code — and matched them with air pollution estimates for those areas.

Researchers looked at several pollutants, but “only sulfur dioxide was related to an increased risk of ALS,” Saucier told lawmakers.

Even the highest levels of exposure tended to fall well within Canadian air quality standards. But that’s “potentially an arbitrary standard” if even low doses are making people ill, Saucier said.

Four clusters

The new study builds on earlier research indicating that rates of ALS might be high in New Brunswick, with “clusters” in certain areas.

Patients and their families have often noted that “there seems to be a lot of ALS” in New Brunswick, Saucier said.

That observation prompted research based on records from the provincial ALS clinic in Fredericton, which identified 187 cases between 2003 and 2013.

That preliminary analysis, published in 2016 found an annual rate of 2.5 cases annually per 100,000 people in New Brunswick. In contrast, most countries around the world typically see one or two cases per 100,000 people.

The 2016 analysis also suggested that several clusters with a “high incidence” of ALS exist in New Brunswick — namely in Bathurst, Edmundston, Saint Paul, and Wilmot.

Saucier said he would like to see an updated study to determine whether clusters still exist in those areas.

Big emitters

In his presentation to lawmakers, Saucier noted that the “biggest cluster” identified by researchers was in Bathurst — which happens to be located near the top emitters of sulfur dioxide in the province.

He didn’t name those emitters in his presentation, but confirmed in an interview that he was referring to the Glencore smelter and the coal-burning Belledune generating station.

The smelter closed in 2019 and is now being decommissioned, while NB Power has controversial plans to convert the generating station to burn wood pellets by 2030.

Both sites are located about 45 kilometres north of Bathurst. More research is needed to determine whether industrial activity is at the root of ALS cases there, Saucier said.

Kimberly Carter, head of the ALS Society of New Brunswick and Nova Scotia, called for more research into environmental toxins. “It hasn’t been explored nearly as much as it needs to be,” she said.

Bathurst mayor Kim Chamberlain didn’t respond to a request for comment for this story.

Genome sequencing

About 10 per cent of all ALS cases are believed to hereditary, while the remainder are “sporadic,” meaning their exact causes are unknown.

Researchers hypothesize that various genetic and environmental factors could be at work, but it’s hard to arrive at definite conclusions, said David Taylor, chief scientific officer at the ALS Society of Canada.

“There are a lot of places in the world with very high exposure to things like sulfur dioxide, particularly islands where there’s volcanoes, for example, and we don’t see higher incidence of ALS in those areas,” the longtime ALS researcher said in an interview.

“It could be that the environmental factors are triggering it in certain people with certain genetic backgrounds.”

Research has progressed considerably in recent years, he said, particularly with advances in genome sequencing. He said ALS research remains underfunded, even with fundraising efforts such as the ice bucket challenge.

Air quality standards

In recent decades, emissions of pollutants including sulfur dioxide have dropped substantially massively across Canada, including in New Brunswick.

Saucier said that air quality improvements in Canada are linked with “substantial health gains,” citing research published in The Lancet this year.

The updates currently under consideration include tighter provincial limits on sulfur dioxide emissions, including an annual average of about four parts per million, down from to the current provincial standard of 23 ppm annually.

But Saucier cautioned that adverse health effects may still exist below that level, as shown by his study.

He called for continuous reductions in pollution. “The standards we have right now just reflect the current levels of pollution we’re living in,” he said.

In his dissertation, he also called for “more incentives for a shift to green energy through more government grants and investments” — to keep industry from closing up shop entirely.

David Gordon Koch is a journalist with the NB Media Co-op. This reporting has been made possible in part by the Government of Canada, via the Local Journalism Initiative.

This story was updated at 3:30 p.m. on Oct. 30, 2025.