Their conclusion is at odds with the substance’s track record — in the last five years alone, H2S has killed at least one oilpatch worker, sickened dozens of others and left livestock dead in a pasture in a small corner of Saskatchewan.

Staff at Health Canada and Environment and Climate Change Canada came to this conclusion in a draft assessment of hydrogen sulfide, published in September. The proposal found that the gas, also known as H2S or sour gas, does not enter the environment in quantities, concentrations or conditions “that constitute or may constitute a danger in Canada to human life or health.”

A corrosive gas that is fatal to humans in high concentrations is a non-toxic substance under Canadian environmental law, say federal researchers in a new proposal.

A coalition of scientists, lawyers, doctors and environmental advocates, however, is concerned with that interpretation. The government “has failed to adopt a science-based, precautionary approach” to assessing H2S health risks in Canada, they wrote in a captious letter sent to Environment Canada during the H2S proposal’s public commentary period last month.

In emailed comments, a Health Canada spokeswoman said that “occupational exposure falls under provincial jurisdiction,” and is not included in general population risk assessments under CEPA.

According to the federal proposal however, such industrial releases aren’t representative of ambient conditions in Canada, and therefore “not considered relevant” in an assessment of H2S under the Canadian Environmental Protection Act (CEPA). If the government approves the draft proposal next year, it means Ottawa will not have the authority to write new codes of practice, management programs or legally-binding safety rules to regulate the gas under CEPA.

National Observer, the Toronto Star and Global News compiled a list of oil and gas industry run-ins with H2S that resulted in injury or death in a series of special reports published in October.

Sour gas, known for its trademark rotten egg smell, is commonly found in hot springs, volcanic gases and biological waste, but can also leak from the wellheads, tanks, pipes and flare stacks of the oilfields. That’s where most egregious, high-concentration encounters tend to occur.

The department will consider spills or emergency situations in risk assessments, it added, if they occur so frequently that they form part of "normal" operations.

“Health Canada does not consider industrial incidents like accidental spills or emergency situations in its assessments, even if they could result in off-site exposure that could impact the general population,” said the department in response to emailed questions. “Its assessments focus on releases that occur during normal operating conditions rather than exceptional circumstances."

Even if dangerous concentrations waft into communities as a result of an oilpatch accident, Health Canada says it does not factor them into assessments under CEPA.

A joint media investigation published by National Observer, The Toronto Star, and Global News, however, has uncovered harmful encounters with sour gas that occurred outside of the oilpatch and in residential settings. In October 2012, for example, a teenager drove through a toxic plume of H2S outside a relative’s home in southeastern Saskatchewan, and immediately started vomiting. The youngster missed school for several days.

According to the federal researchers, the risk of encountering harmful concentrations of H2S in Canadian air or water is low. High-concentration industrial releases can cause pulmonary edema and severe neurological effects, they note, but such concentrations are “several orders of magnitude higher” than those encountered in a “community setting,” and therefore not considered a relevant measure of risk for the general population.

“It's like saying cancer is not a disease,” he said in an interview. “I'd like them to sit in front of me and tell me they're doing that. I'd tell them what I think about it.”

The plan doesn’t sit well with the victims of H2S exposure either — Jeff Crawford, a former oilfield worker who lives with permanent disability as a result of the gas, called the non-toxic assessment “incredible.” Crawford was hit in the face by a mixture containing H2S on the job in 2014, and today, suffers from PTSD, anxiety, dizziness and difficulty with eating, breathing, speaking, smelling and sleeping.

Additional monitoring, inspection, data collection and measurement takes place within the oilpatch to protect workers and the public from rogue H2S emissions that may find their way into unwary communities.

Hydrogen sulfide, Health Canada noted, is already subject to a number of provincial, territorial and federal regulations on emergencies, hazardous materials, environmental and air quality, and occupational health and safety. Those include three existing measures under CEPA, which would remain in effect if Ottawa declined to list the substance as toxic.

But industry doesn’t always follow those rules, found the media investigation, conducted in partnership with journalism schools at the universities of Concordia, Regina, Ryerson and British Columbia, the Michener Awards Foundation and Corporate Mapping Project.

Dozens of H2S infractions have been recorded in Saskatchewan over the last five years. Both industry and the provincial government were aware that H2S leaks were taking place across multiple oilfield operations at the time, the investigation learned, but declined to issue any additional public safety warnings as a result of the incidents. In 2014, oilpatch worker Michael Bunz died on the job after a tank valve burst in southeastern Saskatchewan, spraying oil, water and H2S in his face.

Health Minister Ginette Petitpas Taylor and her department did not respond to questions about whether the federal government should crack down on H2S releases in response to concerns about weak provincial oversight.

Charges have been laid against Bunz’s employer, Nalco Champion, under occupational health and safety legislation for failing to provide him with a respirator and ensure he entered a dangerous situation with a second worker on the day he died from sour gas exposure.

Asked about the federal proposal to rule that H2S, the substance that killed her son, is non-toxic and doesn’t require additional federal safety measures, Dianne Bunz suggested that public safety may not be the primary motivation.

"Look at all the sites that have failed their H2S tests,” she told the investigation. “Not just a little bit — an alarming amount, enough to kill people. And they want to remove it? I find that strange. I don't know why they would do that. Cost probably — no one wants to pay for all of this extra safety stuff."

Video of The Price of Oil: Their son was killed by sour gas

Dianne and Allan Bunz speak about the death of their son Michael, who was killed on the job by H2S. Video by National Observer with footage courtesy of Global News and the University of Regina School of Journalism

Like reading that water ‘isn’t wet’

Critics of the federal H2S proposal argue that industrial encounters like Bunz’s should not be overlooked by the federal government. “The frequency and seriousness” of sour gas releases “indicates the need for greater regulatory oversight” than currently exists, argue Ecojustice, the Environmental Law Association, Environmental Defence, Prevent Cancer Now and the Canadian Association of Physicians for the Environment.

CEPA requires the federal government to regulate any substance that “may enter the environment” in quantities, concentrations or conditions that “may constitute a danger” to human life or health. It does not say anywhere in the legislation that industrial incidents and workplace exposure cannot be considered under the act.

A 1997 ruling in the Supreme Court of Canada further confirmed that federal action to protect the public from toxic substances does not interfere with provincial powers. The split 5-4 decision was related to the dumping of toxic polychlorinated biphenyls by Hydro-Québec, but it had broader implications confirming that CEPA was valid and constituted criminal law.

"The protection of the environment, through prohibitions against toxic substances, constitutes a wholly legitimate public objective in the exercise of the criminal law power," said the majority decision, written by Gérard La Forest. "Protection of the environment is an international problem that requires action by governments at all levels. The legitimate use of the criminal law in no way constitutes an encroachment on provincial legislative power, though it may affect matters falling within the latter’s ambit."

Twenty years later, in the case of hydrogen sulfide, Joseph Castrilli, legal counsel for the Canadian Environmental Law Association, agreed. He said both provincial regulation and any new federal regulation of the substance under CEPA "can live together" simply enough — industry would just have to comply with the most stringent of the two standards.

“The only limitation of provincial law is that if there are two regulations that basically deal with the same subject matter, then the provincial regulation can only be more stringent than the federal one,” he said in an interview.

If the federal government ruled that H2S were toxic under CEPA, Castrilli added, it could also create a number of non-regulatory measures to improve public safety, including risk management programs and voluntary codes of practice, that wouldn't step on any provincial toes.

That’s what makes the federal government’s proposal such a mystery, say the environmental, health and legal groups in their letter. What’s the harm in ruling H2S as toxic?

“That H2S is toxic should be beyond debate,” it reads. “It is plain that releases of H2S may occur as a result of oil and gas operations… It is equally plain that a release may constitute a danger in Canada to human life or health.”

The federal proposal — while not yet finalized — also dismisses H2S’s rotten smell as a “nuisance,” without “scientific or legal justification,” it argues, and did not base its decision on the very lowest H2S exposures that are known to cause adverse health effects to humans.

Its focus on the general population, the groups say, also fails to consider vulnerable communities living near industrial operations, whose quality of life may be compromised by constant odours or even endangered in the event of a leak or spill.

“It’s kind of like reading that water isn’t wet,” said Elaine MacDonald, an environmental engineer at Ecojustice and director of its healthy communities program.

“That’s why we decided to write the letter. We couldn’t let it go... This is probably close to a 10 out of 10 in terms of ignoring the evidence.”

Science Minister Kirsty Duncan declined to comment on whether the federal proposal was evidence and science-based, and requests for comment from Environment Canada on human health and sour gas were referred to the health department.

Health Minister Ginette Petitpas Taylor, who conducted the draft assessment in partnership with the environment minister, did not respond directly to written questions, but issued the following statement via email:

“Canada’s Chemicals Management Plan is a world-leading program that is contributing towards the global goal of sound management of chemicals. In Canada, hydrogen sulfide is subject to a number of risk management measures, which are included in provincial and territorial regulations and guidelines for air quality, including the control of releases from industry.”

Ginette Petitpas Taylor, now Canada's federal health minister, takes media questions on Parliament Hill in Ottawa on June 19, 2017. Photo by Alex Tétreault

Federal plan acknowledges data shortfalls

According to Health Canada, it’s not “unusual” for an assessment under CEPA to rule that a substance with highly hazardous properties is non-toxic. In May 2016, for example, the federal government determined that a group of azo dyes — known carcinogens — were non-toxic, since their exposure to people is very low, or non-existent.

But there are data gaps in their assessment of human health and H2S, wrote the researchers who submitted the draft assessment for sour gas. Long-term chronic experimental studies on the gas’s impact on human health are either limited or non-existent, the proposal notes, as is data on industrial releases in certain sectors (metal and metal refining, for example) located close to human populations. Researchers did however, access and consider decades of hourly H2S measurements taken in the air near pulp and paper mills, oil and gas fields, livestock farms and more.

The federal government said the assessment also considered exposure to people who live near industrial facilities, but that “focus on general population exposure,” has been its practice since the inception of the Chemicals Management Program — a sweeping evaluation of more than 4,000 chemical substances under CEPA with a deadline of March 2021.

That evaluation takes place as the federal government deliberates changes to the aging legislation, which has not been updated since 1999. A June 2017 report by the Standing Committee on Environment and Sustainable Development identified several key “weaknesses” in CEPA’s regulatory framework, and made a number of recommendations that could impact what kind information it considers in assessments. Several of them include special consideration for “vulnerable communities,” like those living in close proximity to industry operations.

The federal government has said it will respond to those recommendations before June 2018. But to rule on H2S while the entire act is called into question is “definitely irresponsible,” said former corporate lawyer and environmental law expert Jason MacLean.

“It looks like a decision that’s irrational and negligent on its face and it looks even worse I think to be doing this while (CEPA) is under consideration,” the assistant law professor at University of Saskatchewan, told the investigation. “It looks hasty, it looks rushed, and that’s not in the public interest.”

If the federal plan is approved however, and someone gets sick from ambient exposure to H2S, MacLean said it would be “an uphill battle” to try and sue the federal government for its ruling that the substance isn’t toxic under CEPA. One would have to prove that Ottawa was negligent and “flying in the face of independent scientific findings” in its chemicals assessment, he explained, but “any amount of legitimate scientific doubt” to those claims could probably take the case apart in the courts.

Hydrogen sulfide can sometimes leak from pump jacks like this, captured in September 2017 north of Oxbow, Sask. Photo by Mark Taylor for the Toronto Star

Independent scientist backs assessment

Geoff Granville, a Calgary-based scientist with expertise on managing the risks of toxic substances, said in an interview that he agrees with the government’s draft assessment of H2S. People in a non-occupational setting are not usually at risk, he explained, and if an incident does occur outside of the workplace, it may be accidental with unknown or extraordinary causes.

That’s tough for the federal government to regulate preemptively, said Granville, and not within the scope of CEPA: “It’s not (about) risk based on an accident situation, otherwise cars are toxic. That makes no sense. It’s not accident driven, it’s got to be by the way the world operates.”

Encounters based on industrial and workplace exposure, he added, are another matter entirely. Bad industry practice is unacceptable, said Granville, but since most industry regulation falls within the jurisdiction of provincial regulators and governments, it may be more practical for Ottawa to find other methods of encouraging adherence to H2S regulations than cracking down with the full force of CEPA.

The question then becomes, said Granville, what more can the federal government do to protect public safety?

He suggested co-operation between jurisdictions to help address people’s “very natural” fear of H2S, like strengthening whistleblower programs or starting a conversation about how to handle to low, foul-smelling but ultimately not dangerous levels of H2S. In the context of CEPA, he said the word ‘toxic’ takes on a legal meaning of its own, and much of the outrage with the federal plan has to do with semantics.

“So how do the feds shame a provincial environmental ministry to step up and really regulate and do its job better?” he asked. “Whether you call it toxic or not, I actually think the feds could say, ‘We’re concerned about low levels of exposure to the public, which does happen, and therefore, we’re willing to prepare something to work with other jurisdictions and do x, y, z.”

The government’s assessment isn’t final, and while the public commentary period has officially closed, Health Canada is encouraging stakeholders to submit “any additional information that should be taken into consideration.” In conjunction with Environment Canada, the department will publish a summary of public commentary on its proposal, its responses to those comments, and its final assessment of H2S in 2018.