The U.S. Environmental Protection Agency has proposed reapproving dicamba, a weedkiller banned twice by federal courts for its destructive effects on crops and ecosystems. This move has reignited concerns from environmental groups, scientists, and neighboring farmers—many of whom say the herbicide’s history speaks for itself.

Dicamba has been banned twice by federal courts for causing widespread damage.

A Volatile Chemical That Doesn’t Stay Put

Developed in the 1960s, dicamba was long used in limited agricultural applications. But its use surged after 2016, when companies like Monsanto released genetically modified soybean and cotton seeds designed to tolerate the herbicide. Farmers began blanketing fields with dicamba, hoping to combat glyphosate-resistant “superweeds.” But instead of staying put, the chemical moved.

Dicamba is notoriously volatile. Under warm conditions, it vaporizes and drifts—sometimes for miles. Even when applied correctly, it doesn’t stay where it's sprayed. Neighboring crops, wildflowers, trees, and native plants have suffered the consequences, along with the pollinators and wildlife that depend on them.

One Tennessee farmer reported damage to his soybeans despite being assured by nearby growers that dicamba hadn’t been used within a mile and a half, suggesting the chemical traveled at least two miles through the air, according to The Washington Post.

Dicamba drifts easily, harming crops, trees, and native plants miles away.

Federal Courts and Repeated Bans

Federal courts have taken issue with these effects. In 2020 and again in 2024, they struck down EPA registrations, citing the agency’s failure to account for the widespread and “undisputed” harm caused by dicamba.

The 9th Circuit Court of Appeals said the herbicide had damaged millions of acres and “tore the social fabric” of farming communities. Yet despite these rulings, the EPA has now proposed a new path forward for dicamba use—one that environmentalists say lacks meaningful change.

New Rules, Same Risks

The new proposal includes limitations such as not spraying above 95°F and requiring drift-reduction agents when it’s over 75°F. But critics argue the agency is simply repackaging failed strategies.

“All the previous restrictions didn’t work,” Bill Freese of the Center for Food Safety told The New York Times. “This loosens the already inadequate rules.”

Impacts on Human and Animal Health

The chemical’s risks extend beyond crops. Dicamba exposure has been linked to respiratory irritation, vomiting, and in some cases, muscle spasms and eye damage in humans and animals, according to the National Pesticide Information Center. Though pure dicamba has low toxicity through skin contact or inhalation, ingestion can lead to gastrointestinal distress. In animals, including birds and pets, symptoms range from weakness to drooling and disorientation.

The herbicide has pitted neighbors against each other in farming communities.

Cancer and Long-Term Exposure

Cancer concerns remain disputed. Some studies have suggested weak links to lung and colon cancer among pesticide applicators, though the EPA maintains that dicamba is not likely to be carcinogenic. Still, researchers continue to explore long-term effects on both people and ecosystems, particularly given dicamba’s persistence in the soil and potential for runoff into waterways, where it can affect aquatic life.

Industry Influence and Regulatory Concerns

In its environmental review, the EPA acknowledged some risks to plants but concluded that dicamba doesn’t pose a significant threat to human health or the environment. Yet that conclusion comes amid growing scrutiny over regulatory capture. Just weeks before the proposal was released, the agency appointed Kyle Kunkler—a former lobbyist for the American Soybean Association—to a top position in its Office of Chemical Safety, raising concerns about the influence of industry on public health decisions, Reuters reports.

Animals exposed to dicamba may show disorientation, salivation, and muscle tremors.

Communities in the Crosshairs

Meanwhile, farmers without access to dicamba-resistant seeds fear losing their harvests—not from weeds, but from chemical drift. Rural communities have already suffered the fallout, as neighbors turn against each other over damaged crops and shifting liability. And native ecosystems face a quieter threat: the slow disappearance of wild plants critical to pollinators and biodiversity.

The Legal Fight Isn’t Over

With the EPA’s public comment period underway, legal action looms once more. Nathan Donley of the Center for Biological Diversity told The Associated Press that the move was “a hijacking” of environmental policy by industry interest. Conservation groups are preparing to challenge the agency again in court.

For now, the future of dicamba lies in a precarious balance—between the economic demands of industrial farming and the rights of communities, ecosystems, and future generations not to be collateral damage in the war on weeds.

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