Pesticides made from a class of cancer-causing toxic chemicals that never degrade are being used on Canadian crops despite global concerns about their impact on humans and the environment.

PFAS are a class of thousands of chemicals that do not break down naturally in the environment. Cherished by industry for being able to resist grease and water, they are used in everything from rain gear to food packaging. Researchers have found them nearly everywhere on Earth, including remote parts of the Arctic — and in most human bodies.

In pesticides, PFAS are used as the so-called "active" ingredient — the killing agent — and as an additive to give them desirable properties such as water resistance. These "PFAS-ticides" have become more widely used in recent years to remedy increasing herbicide resistance to older types of pesticides. At least ten are currently approved for use in Canada.

Amid growing concern about the chemicals's health impacts, the European Union, the U.S. and several American states have recently moved to restrict their use or ban them entirely. Canada’s Minister of Environment and Climate Change Steven Guilbeault has even said that a "proactive and precautionary approach is needed" in Canada for PFAS and pledged to implement rules regulating the chemicals as a class.

But the federal government is required to make one exception: pesticides.

A quirk of Canadian law exempts pesticides from most federal rules, including the Canadian Environmental Protection Act (CEPA). That has created a "remarkable" situation where Canada's Pest Management Regulatory Agency (PMRA) is approving PFAS-containing pesticides even as Environment and Climate Change Canada considers restricting their use, said Laura Bowman, a lawyer with Ecojustice that specializes in pesticides.

The approval of PFAS-ticides by Canada's pesticide regulator comes amid intense criticism of the agency's "obsolete" approach to pesticide regulation, according to prominent health researcher Bruce Lanphear. Last year, Canada's National Observer found the PMRA minimized health and environmental concerns from its own scientists about the toxic pesticide chlorpyrifos and downplayed the health risks of the pesticide dimethyl tetrachloroterephtalate (DCPA).

In a statement, a PMRA spokesperson confirmed "that potential risk management measures on PFAS in pesticides would be evaluated by the Pest Management Regulatory Agency," not Environment and Climate Change Canada, which is responsible for most PFAS chemicals.

The PMRA does not provide accurate data about where and when pesticides are used, nor how much has been applied, making it hard to assess how many PFAS-ticides are used in the country.

The EU, the U.S., and several states have all taken steps to restrict or outright ban pesticides that contain #PFAS. A quirk of Canadian law sees a regulator approving their use even as the environment minister is mulling restrictions.

However, a European study published earlier this year found that the prevalence residue from the ten most-used PFAS-based pesticides tripled between 2011 and 2021 in fruits and vegetables. Eight of the most common European PFAS-ticides are also approved for use in Canada; three of them were sold in volumes exceeding 10,000 kilograms of active ingredient in 2020, according to PMRA sales data.

Bowman said that a 2022 decision by the PMRA to approve once such PFAS-based pesticide, tiafenacil, suggests pesticides that contain or break down into PFAS could become more common.

Tiafenacil breaks down into the PFAS compound trifluoroacetic acid — or TFA — which is thought to impair fertility and child development. Industry lobbyists note it can occur naturally; however, most TFA comes from human activity, including pesticide use.

In 2020, the PMRA proposed to ban another pesticide that degraded into TFA, citing the compound's risk. But the more recent 2022 approval of tiafenacil suggests the agency is backtracking from these earlier hesitations, setting the stage for more TFA-generating pesticide approvals later this year, she said.

"We're anticipating a big fight about PFAS," she said.

Still, advocates emphasize the biggest problem is the "false distinction" between Canada's efforts to reduce the use of non-agricultural PFAS chemicals and those found in pesticides, said Cassie Barker, the director of Environmental Defence's toxics program.

"The idea that we could have this class of chemicals be super toxic and could still be sprayed onto our food and almost directly into our water is a huge problem," she said.

Updates and corrections

| Corrections policy
June 3, 2024, 04:00 pm

Editor's note: This story was updated to clarify that the Pest Management Regulatory Agency proposed to ban, but did not ban, a TFA-generating pesticide in 2020.

PMRA falls under the control of the Public Health Agency of Canada [PHAC] which has been captured by the pharmaceutical industry. Dr. Howard Njoo, the Deputy Chief Public Health Officer is the king pin in this operation and has the Minister's ear. He is just one of many industry lobbyists who have woven themselves into the fabric of government. Both government and medicine have failed to protect the public which is one of their main tasks. Lobbyists are the reason why we don't have the pharmacare we need and why Canada is promoting small nuclear reactors along with carbon capture and storage. It's time to insist on some civilian oversight

Little can be done in Canada to protect us. Big Oil has totally captured Alberta Politics, big Pharma our drug supply and Big Chemical and Agriculture our Pesticides approval. Dealing with our federal health and Pesticides and consumer protection agencies, impossible, I gave up

Pesticides are by definition toxic. If they weren’t, they wouldn’t kill pests. Pesticides are also essential in agriculture because we couldn’t produce enough food without them. Even organic farmers use “natural” pesticides, i.e. toxic chemicals that are produced by organisms in the natural world. My understanding is that natural toxins can be just as dangerous as synthetic ones. In any case, I am a bit confused by this article because it makes no mention of exposure levels. Is one to infer that the pesticides in question are a problem in Canada because overuse is leading to dangerously high exposure levels? Or is the inference that pesticides need to be banned completely because even trace quantities, measured in parts per billion, are unacceptable? And are the “natural toxins” employed by organic farmers exempt from concern?