This week, thick wildfire smoke blankets parts of North America from fires burning across Canada and northern Minnesota. Over 800 wildfires are burning through Canadian forests right now and firefighters in the United States are working to contain 48 uncontained large fires.
Most of our conversations about glyphosate focus on farms, food, and health. But across North America, thousands of hectares of public forest land are sprayed with glyphosate-based herbicides every year, often from the air, over land that communities depend on for clean water, wildlife, and in many cases, food and cultural practice.
Glyphosate is primarily used in forestry to kill broadleaf species like birch, poplar, and berry plants that compete with commercially valuable conifers, to control invasive plant species, and to clear pipeline and road corridors. This makes for more uniform and more flammable forests.
Glyphosate and Wildfire
Glyphosate in forestry systematically eliminates plants that act as a fire buffer while also leaving behind dead vegetation, creating more flammable material in the forest. The aspen and birch trees that are impacted by glyphosate spraying slow fire spread naturally. They keep flames low to the ground where firefighters can contain them. When conifer forests burn, they feed the conditions that make the next fire season worse because they release more than twice the carbon of deciduous forests.
Glyphosate Spraying in the United States
A year-long investigation by Mother Jones found that the US Forest Service and its timber industry partners have been spraying glyphosate across clear-cut and fire-damaged forests at record levels. California alone sprayed 266,000 pounds of glyphosate on forests in 2023, five times the amount sprayed 20 years ago, making forest spraying the fastest-growing market for glyphosate in the state. The article from Mother Jones also outlines another concerning issue – glyphosate is regularly sprayed in forests and public lands where many people forage for food. This happens in the United States and across Canada. Many people enjoying foraged berries and mushrooms are unknowingly consuming this probable carcinogen.
Glyphosate Spraying in Canada
In Ontario, a grassroots campaign called Stop the Spray Ontario has been working on this issue for years. The group was started by a bush pilot and hunter named Joel Theriault. He became convinced something was wrong after harvesting a black bear that made his friends and family sick with symptoms that matched glyphosate overexposure. Last summer a planned aerial herbicide spray was halted thanks to a series of protests led by Indigenous communities and environmental advocates, including Stop the Spray Ontario.
Ontario banned cosmetic pesticide use in 2009 to protect families, children, pets, and communities from unnecessary chemical exposure. However, forestry was explicitly exempted. So, while glyphosate was banned from lawns and schoolyards, it is still being sprayed over the Crown forests, impacting land that rural families, Indigenous communities, and wildlife depend on for food, water, and cultural practices.
How the Industry has Responded – Switching Chemicals
In December 2025 a study that had been cited by regulators across the globe for 25 years to justify glyphosate was retracted over evidence it was ghostwritten by Monsanto and built on the company’s own unpublished research.
The industry in provinces like Alberta and Ontario is quietly switching to alternative, still problematic chemicals like Triclopyr and Imazapyr. Triclopyr is moderately to highly toxic to freshwater plants and fish, can stay in soil for up to a year or more, and its breakdown products pose significant risks to groundwater and surface water. Imazapyr stays in soil for over a year, moves readily through most soil types, and has contaminated surface and groundwater after arial sprays. Plants that are not being targeted, including those that are food and medicine to Indigenous communities, can still be reached by spray drift. Swapping one herbicide for another doesn’t actually fix the problems we’re outlining.
The Fight in the United States
Over the past decade, hundreds of thousands of cancer patients filed suit against Bayer, arguing that glyphosate caused their non-Hodgkin lymphoma and that Monsanto failed to warn them. Bayer has paid out billions in settlements, and on June 25, 2026, the Supreme Court ruled 7-2 in favor of Bayer, effectively closing the door on remaining state-level failure-to-warn claims and tossing out around 100,000 pending cases. The Trump administration has also filed an amicus brief in support of Bayer, designating glyphosate as critical to national defense under the Defense Production Act.
What can we do?
Change is possible. Quebec banned glyphosate in its public forests in 2001 and has managed its forests without it for 25 years. Last summer, because of organized community pressure aerial spraying has stopped in three Ontario forest districts.
OCA has been in this fight for 30 years. We launched the Millions Against Monsanto campaign in the mid-1990s. In 2017, OCA and Beyond Pesticides sued Monsanto for misleading the public about Roundup’s safety, and a federal judge ruled in OCA’s favor. OCA has tested major food brands for glyphosate contamination, sued companies that marketed contaminated products as natural, and was a founding organizer of the Monsanto Tribunal in The Hague, where judges concluded that Monsanto’s activities violated basic human rights. Bayer’s victory in the Supreme Court in June of 2026 is a setback, but bills restricting or banning glyphosate have already been introduced in a dozen states and OCA is working to help citizens push for the ban across the country.
If you’re in the United States, your state legislators are now the most direct path to accountability. If you’re in Canada, follow and support Stop the Spray.
