The EPA wants to green-light approval for a twice-banned herbicide

The Environmental Protection Agency wants to reallow the use of dicamba as a commercial weed killer. The proposal comes despite the herbicide having been blocked twice by federal courts because of its potential for causing ecological damage.

Try, try, try again

Dicamba has been a commonly used weed killer for the past 50 years, but its usage increased after 2016 when agricultural giant Monsanto genetically engineered crops to be resistant to it. This allowed farmers to spray the crops with the herbicide and have only the weeds die. The EPA also approved conditional registrations of dicamba-based herbicides.

However, environmental groups sued the EPA for its approval of dicamba because of the weed killer's potential to "drift away from the intended target, especially during warmer temperatures, and harm neighboring crops, nearby ecosystems and rural communities," said The Washington Post. As a result, the U.S. Court of Appeals for the Ninth Circuit ruled against the EPA and vacated the herbicide's registration. The court noted the EPA "substantially understated risks that it acknowledged and failed entirely to acknowledge other risks," of dicamba, said the 2020 court decision.

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Following the decision, the EPA once again registered dicamba herbicides for use on genetically modified soybeans and cotton. Environmental groups challenged the EPA, and in 2024, a federal court vacated the registrations and prevented the sale of the herbicide for a second time. But the third time's the charm. The EPA conducted a review of dicamba and did not find any "dietary, aggregate, non-occupational or occupational risks of concern for potential human health exposure," said the 2025 review. The EPA did find, however, that the herbicide "does pose risks of concern" to certain plants. To combat the risks, the EPA is "proposing restrictions on how much of the chemical can be applied and when," said Reuters.

While the EPA's analysis found no risk to human health from dicamba, previous analysis showed "elevated risk of liver and intrahepatic bile duct cancers," as well as a specific type of leukemia, said a 2020 study published in the International Journal of Epidemiology. "None of these associations has been previously reported in the epidemiologic literature."

In the weeds

The EPA's proposal has gotten mixed reactions. Dicamba is a "critical crop-protection tool for soybean farmers, particularly in managing herbicide-resistant weeds," which can "quickly overtake fields, competing with soybeans for sunlight, water and nutrients and ultimately leading to significant yield losses," said a spokesperson for the American Soybean Association in a statement. In addition, the herbicide, "when used according to the label, can be used safely and successfully on-target," said the pharmaceutical company Bayer, which has created one of the dicamba herbicides mentioned in the proposal.

Those opposed have cited severe ecological risk. "If we allow these proposed decisions to go through, farmers and residents throughout rural America will again see their crops, trees and home gardens decimated by dicamba drift, and natural areas like wildlife refuges will also suffer," said Bill Freese, the science director at Center for Food Safety, in a statement by the Center for Biological Diversity.

The Trump administration has also come under fire with one claim that it is "hitting new heights of absurdity" in trying to bring back an herbicide that has been blocked twice, said Nathan Donley, the environmental health science director at the Center for Biological Diversity. Last month, Kyle Kunkler, who is a "former soybean industry lobbyist who has been a vocal proponent of dicamba," became the deputy assistant administrator of the EPA's Office of Chemical Safety and Pollution Prevention," said The New York Times.