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Across North America, ethylene oxide is used to sterilize medical equipment. The odorless gas is useful, but it’s also toxic to humans when high amounts are breathed in. And, according to a newly obtained document, the federal government is unclear how much of the chemical companies release into Canadian air.
The document is a draft version of a Health Canada report on ethylene oxide obtained by The Narwhal through access to information legislation. It’s part of an ongoing “performance measurement evaluation” the federal department is doing to assess the health risks of 13 substances classified as toxic under the Canadian Environmental Protection Act.
Currently, guidelines developed in 2005 stipulate that companies that use, transfer or dispose of 10 kilograms or more of ethylene oxide must self-report to the National Pollutant Release Inventory. In the draft report, Health Canada notes “significant” amounts of the chemical might be going unreported, due to “a possible problem with compliance or with the reporting threshold of the [pollutant release inventory], which may be set too high … .”
The draft also notes Environment and Climate Change Canada’s “air quality laboratory faces challenges in both sampling and analyzing [ethylene oxide]” due to technological limitations. It also says ethylene oxide is not monitored nationally because “there is no accredited method to report data.”
Ethylene oxide has been considered to have “a probability of harm at any level of exposure” by Environment Canada and Health Canada since 1999. But a quarter-century later, there are no enforceable federal limits for the carcinogenic toxin, as The Narwhal reported in a May 2024 story about medical sterilization company Sterigenics, which has long used the chemical at its operations in the Greater Toronto Area.
Sotera Health, the Ohio-based company that owns Sterigenics in Mississauga, Ont., has been named in a series of American lawsuits brought by claimants who say they developed illnesses, particularly cancers including leukemia, myeloma, lymphoma and breast cancer, because of ethylene oxide exposure. The company has agreed to pay American claimants in Illinois and Georgia almost US$450 million, although it’s also said the settlements should not be considered an “admission of liability.”
Canada’s single biggest reporter of ethylene oxide use between 2020 and 2023 was the waste management company Clean Harbors. Its Red Deer, Alta., facility topped the national list all four of those years, the most recent for which data is available. The newly obtained draft report shows several potential sources of ethylene oxide emissions across the country for which Health Canada says it has incomplete data on just how much is going into the air.
Most are sterilization facilities, but emissions also occur when leftover ethylene oxide products, like used canisters from the sterilization sector, are collected and transferred to landfills or other sites where they can be safely disposed. There is very little public information on exactly how this waste and transfer industry operates.
Elaine MacDonald, the program director of healthy communities at the charity Ecojustice, said Canada too often defaults to softer approaches to monitoring, rather than “enforceable regulations and standards” for ethylene oxide emissions.
“We really don’t have any rules federally” about how much ethylene oxide companies are allowed to empty into the air and environment, she said. “We just have these guidelines that are 20 years out of date.”
The draft report obtained by The Narwhal was being worked on between May and September 2024, perhaps earlier. It notes in its pages several gaps that need to be filled in, including many details on waste disposal and transfer. Health Canada told The Narwhal its planned publication date is summer 2025.
“There’s a big gap to catch up there, and it needs to be done quickly,” MacDonald added. “My one concern is that Canada can take a really long time to get federal regulations and rules into place.”
Canada’s National Pollutant Release Inventory is a public record of releases, disposals and transfers of potentially harmful substances. Reporting is done by companies themselves — including those that use or dispose of 10 kilograms or more of ethylene oxide.
That threshold may be too high, the Health Canada draft notes as it recommends a reduction. As evidence, it points to 2009 air quality tests in B.C. where a number of sites met or exceeded the guideline for the chemical, yet no facilities reported using it to the inventory that year.
This advice is being repeated by Environment and Climate Change Canada. Between October and December, that department held consultations on what lowering the threshold could mean for industries and researchers that use the chemical, promising a decision on reporting requirements in “winter 2025.” Its consultation document proposes reducing the reporting requirement to the release, disposal or transfer of just one kilogram of ethylene oxide, instead of 10.
“New information has come to light in both Canada and the United States that shows [ethylene oxide] toxicity is more potent than originally thought,” the report reads, including a 2016 publication from the U.S. Environmental Protection Agency showing inhalation of ethylene oxide is 30 times more toxic than previously thought.
‘Like using a machine gun to kill a rabbit’
— Paul Belanger, Keepers of the Water, on using ethylene oxide for medical sterilization
“We’re missing some facilities, and it’s likely because of that high threshold,” Environment and Climate Change Canada scientist Alicia Berthiaume said in an interview. She was the one tasked with recommending a new reporting limit. “We’re proposing to lower it … so that we can really capture the users and releasers that are contributing to emissions in Canada.”
Berthiaume said the lower threshold shouldn’t be a challenge for industry to meet given “substantially more stringent requirements coming online in the U.S.” In spring 2024, the U.S. Environmental Protection Agency tightened air pollution controls on the sterilization sector, seeking to reduce the industry’s emissions by more than 90 per cent.
Even with a lowered threshold, companies would still be self-reporting their use of ethylene oxide. Observers are critical.
“How well are the fugitive emissions being tracked? What we’re counting on right now is reporting from … producers, and I’m always skeptical of those numbers because that’s self-reporting,” Paul Belanger, science advisor for the Alberta environmental organization Keepers of the Water, said. “The emissions, I’m assuming, are probably worse than what they’re reporting.”
Even if the amount that triggers a federal reporting requirement is lowered, it would be up to provinces to initiate any new environmental or health monitoring, as they have authority over air emissions and protections.
Between 1993 and 2013, ethylene oxide reporting across Canada was on a fairly steady decline. Then, in 2014, it began moving up again. The national pollution inventory saw Canada’s highest-ever reporting of ethylene oxide releases, disposals and transfers in 2021, the Health Canada draft report says.
Much of that increase occurred in Alberta, a drastically outsized contributor to ethylene oxide use. In 2021 the province contributed 77 per cent of the entire country’s releases, transfers and disposals. In 2022, although lower, Alberta still contributed 67 per cent of total reported national ethylene oxide use.
In Environment Canada’s document, one Alberta facility stands out: it’s run by Clean Harbors, which provides services like hazardous waste management and emergency spill cleanup for many industries, including government agencies. The company’s location in Red Deer used over 65 per cent of the whole country’s reported ethylene oxide use on the federal inventory in 2022.
Belanger said this information about Alberta’s outsized impact is “not surprising,” especially since he’s known for a while that ethylene oxide is produced with fossil fuels in Alberta.
But use doesn’t necessarily mean emissions and the Health Canada draft shows there’s no clear picture of whether these transfers and waste disposals are emitting anything into the air. The department has a lot of questions about the use of the chemical in waste management. Health Canada’s report reads, “No further information has been provided by industry to explain this process or how it is getting disposed of.”
“I don’t know why this is the case,” one agency staffer wrote in a comment in the draft’s margin, noting they and others had been unable to find out how the disposal and transfer process works, even after asking federal government air quality researchers.
Health Canada doesn’t name Clean Harbors, saying only that “one specific [Alberta] facility reported a significant amount” of ethylene oxide, and that facilities like these “need to be followed up with to better understand this increase.”
When asked by The Narwhal, Environment Canada said the agency does not do routine monitoring of ethylene oxide, nor does it monitor air around individual facilities. That means that so far, no federal tests have been done to determine how much, if any, ethylene oxide Clean Harbors’ Red Deer waste operations are emitting into the air despite high levels of reporting on the inventory. “Staff are currently looking in more detail at this facility” in case there is “a data integrity issue,” a department spokesperson said.
Clean Harbors did not respond to questions about its Alberta operations sent by email. The company’s website says it operates across North America, including in eight provinces.
“I was actually quite surprised how much [ethylene oxide] was being reported in the waste stream,” researcher Fe de Leon of the Canadian Environmental Law Association said after checking the national pollutant registry. “To me, it’s like, okay, so are we not spending enough time looking at that pathway?”
Unlike other provinces, Alberta has not updated its guideline for ethylene oxide levels in air since the chemical was classified as toxic in 2001 — an assessment Environment Canada’s document notes was “based primarily on carcinogenic effects to humans from exposure by inhalation.”
Alberta’s Environment Ministry did not respond to interview requests.
Unlike waste management, the medical sterilization industry has come under intense scrutiny for how its ethylene oxide use could potentially be harming public health, as seen in the U.S. lawsuits against Sterigenics.
In 2021, Environment Canada researchers found “detectable plumes” of ethylene oxide, which they called a “human carcinogen,” near a now-closed Sterigenics factory in a densely populated east Toronto neighbourhood.
In 2022, Sterigenics closed that plant and moved to Mississauga, on the west side of Toronto. Sterigenics did not respond to recent questions about how it is protecting workers and the nearby community from emissions: last August, it told The Narwhal its “state-of-the-art Mississauga facility deploys the most advanced safety and environmental technology available and was constructed in full compliance with federal, provincial and local regulations.”
Neither the City of Mississauga nor the federal government monitors the air outside the factory for ethylene oxide: when asked, both noted that is a job for the province. In the past year, The Narwhal has sent 17 emails and made five phone calls asking Ontario’s Ministry of the Environment, Conservation and Parks how it protects Mississauga residents from ethylene oxide and if there are plans to study the chemical further. In response, it has received only two emails that said the ministry does “not have any input at this time.”
On its website, Sterigenics maintains that using ethylene oxide is “the sterilization method with the broadest application available for medical products and medical devices.”
But governments seem less convinced. When establishing stricter emissions controls on the sterilization sector last spring, the U.S. Environmental Protection Agency called ethylene oxide “one of the most potent cancer-causing chemicals.”
And in its draft report, Health Canada disagrees ethylene oxide is the only sterilization option. “There seems to be readily available alternatives that are safer and less costly,” the draft evaluation reads, proposing hydrogen peroxide and steam, among others.
“Something as toxic as ethylene oxide, where there’s potential points of exposure throughout the country … requires some really strong rules and high levels of control,” MacDonald said. “If there’s sectors that are using it unnecessarily, where they’re safer options, that should definitely be a consideration, too.”
Belanger echoed MacDonald’s desire to phase out ethylene oxide, calling the chemical “unstable” and “dangerous,” adding its use for sterilization instead of alternatives is “like using a machine gun to kill a rabbit.”
Health Canada’s evaluation, when it is eventually published, will not be a rule or regulation. Rather, it’s an assessment of how well existing risk management strategies are working, and to identify “any areas of improvement that should be addressed moving forward” in protecting Canadians. The draft notes ethylene oxide is no longer allowed in cosmetics or used as a food additive.
Given the report is still just a draft, it remains unclear whether the federal government considers the air quality risk posed by ethylene oxide to have been effectively managed already. As of the date The Narwhal received these records in fall 2024, the Health Canada draft concluded “the Government of Canada has achieved its objectives set out to protect Canadians from the risks posed by this substance.”
But in January the department told The Narwhal that “no conclusions have been made at this time.”
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