The EPA allowed pesticide giant Bayer to pick from a menu of regulation options for the controversial and destructive weedkiller dicamba, newly released internal agency documents show.

The documents provide an unusually clear look into the process of developing pesticide regulations, which is typically done out of public view. It shows in detail how the EPA asked Bayer which regulations it wanted, received a response from Bayer, then put Bayer’s choices into a proposed federal rule.

Dicamba is drift prone and kills vegetation and crops for miles around fields where it is sprayed, and is linked to liver cancer and Non-Hodgkin lymphoma. Courts have twice ordered it off the market because of its drift problems, but the EPA has re-approved it.

The EPA solicited Bayer’s input on the level of restrictions to limit dicamba volatility and runoff, ranging from more protective to less protective, records released in ongoing litigation over the substance show. The EPA concluded one presentation with a slide entitled “Registrant response needed” which posed the question “Which mitigation option to go forward with?”

Bayer chose the least protective for one regulation, and the middle of three levels of protection for another regulation. It also got one other change it requested into the rule.

Pesticide regulations are typically a negotiation between industry and the EPA, but the exchange that the documents reveal is “crossing a line”, said Nathan Donley, environmental health science director with the Center for Biological Diversity, which is litigating on the issue.

“The EPA is allowing Bayer to choose its preferred measures to limit dicamba’s damage as if it was ordering up a late-night dinner à la carte from Chili’s,” Donley said. “It becomes troublesome when the EPA allows them to regulate themselves by choosing the mitigations.”

The Center for Biological Diversity and the Center for Food Safety brought the lawsuit. The documents come as the EPA has faced criticism for stacking its leadership with industry veterans. The top four toxics office positions at the EPA are held by former chemical industry leaders, including Kyle Kunkler, a former pesticide industry lobbyist who is now a deputy assistant administrator and oversees the pesticides program.

Despite repeated assurances from the EPA that it has put effective protections in place, dicamba drift has damaged millions of acres of farmland and caused damage to orchards, vegetable farms, home gardens, native plants, trees and wildlife refuges across the country since its first approval in 2016. Experts have found dicamba drift damage to be the worst of any herbicide in the history of US agriculture. Still, the current approval provides even fewer protections from dicamba drift and damage than past approvals, the lawsuit alleges.

In a statement to the Guardian, an EPA spokesperson said: “Make no mistake: this is not a compliance failure; it is the regulatory system working exactly as intended.”

“The agency notifies the [pesticide maker] and works with them to identify possible solutions” to risks, the spokesperson wrote. “[Companies] are permitted to submit mitigation ideas that preserve their product’s utility, and EPA also will independently develop its own proposed mitigations. To be explicitly clear: the registrant does not dictate terms.”

During a May 2025 EPA meeting with Bayer, the agency gave Bayer two mitigation choices that would allegedly address dicamba’s high volatility, which is what makes it drift prone. A more restrictive option would have prevented dicamba applications above 85F, and a less restrictive option would allow applications up to 95F, if the acreage treated was reduced.

The EPA also gave Bayer three options for addressing dicamba runoff, documents show. It then concluded the presentation with a solicitation for Bayer to decide.

An EPA manager then wrote in an email that “the next step in the process beyond the [presentation] is getting feedback from the registrants on what mitigation and mitigation implementation option they would like to move forward with”.

Separate documents obtained by the Center for Biological Diversity showed the plan was presented to Nancy Beck, a controversial former lobbyist for the American Chemistry Council who now leads the EPA’s office of chemical safety.

The revelations drew condemnation from “make America healthy again” (Maha) advocate Kelly Ryerson, who said: “It is now undeniable that the EPA remains fully captured by a crooked collection of pesticide company players who so enthusiastically ignore the substantial losses of farmers and the federal courts who mandated a halt to dicamba use.”

Eight days later, a representative from Bayer emailed the EPA: “After discussion with EPA and reviewing these options carefully, Bayer would like to proceed as described below … ”

Bayer chose the less restrictive option for volatility mitigation, which would allow it to be applied at up to 95 degrees as long as the dicamba-treated area would be reduced. Bayer also wanted another option that the EPA had not proposed, emails show. It would allow full-field dicamba treatments at higher temperatures if dicamba was not tank mixed.

The EPA granted both requests, and Bayer’s preferred option for mitigating run off. These were included in the rules proposed a few months later, documents show.

“In return for this egregiousness, I would like the EPA to propose a menu of options to Maha for significantly decreasing our exposure to known carcinogens and endocrine disruptors,” Ryerson added.