The Environmental Protection Agency has proposed allowing the weed killer dicamba for genetically engineered soybeans and cotton, two crops that are grown extensively in the United States.

This week's recommendation comes after the first Trump administration made the same move, only to have courts block it in 2020 and 2024. This is the first year since 2016 that dicamba has not been allowed to be used on crops, according to Nathan Donley, the environmental health science director at the Center for Biological Diversity, a national conservation nonprofit.

Environmental groups say they will once again go to court to try to block it.

"This is an unfortunate roller coaster ride that the country has been in for about 10 years now, and it's just incredibly sad to see our Environmental Protection Agency being hijacked by this administration and facilitating decisions that are objectively going to make our environment less healthy," Donley said.

The EPA said via email that it "will ensure that farmers have the tools they need to protect crops and provide a healthy and affordable food supply for our country" and the agency is "confident these products won't cause issues for human health or the environment."

The EPA added that the proposal will be open for public comment for 30 days and included a list of proposed guidelines on the use of the three dicamba-containing products in question.

Dicamba is a common weed killer and has been used for over 50 years in the U.S., but it has become more widespread on farms in the past decade, according to data from the EPA and the U.S. Geological Survey.

Researchers have been working to better understand the health risks it might pose to humans. A 2020 study in the International Journal of Epidemiology found that dicamba exposure was linked to some cancers, including liver cancer and a type of leukemia affecting the blood and bone marrow.

Dicamba can also drift far from its intended targets to kill other plants on neighboring farms and in local ecosystems, posing threats to wild flora and fauna, according to the National Wildlife Federation.

An agency can tweak a decision after a court strikes it down, and then dicamba would be approved until a new legal challenge succeeds. Past court rulings on dicamba have taken years, "leaving many farmers with questions and uncertainty in the middle of the growing season," National Agricultural Law Center staff attorney Brigit Rollins said in a background summary of dicamba legal cases.

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