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.”
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.
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.
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.
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.
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.
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.
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