Newly released internal records show the Environmental Protection Agency asked Bayer to choose among proposed safeguards for dicamba, then carried the company’s preferred approaches into federal restrictions governing the controversial weedkiller.

The disclosure, first detailed Sunday by The Guardian, does not establish that Bayer dictated the entire registration decision. It does, however, offer an unusually direct view of the bargaining behind pesticide rules that affect cotton and soybean growers, neighboring farms and ecosystems. EPA says consultation with manufacturers is a routine part of ensuring a pesticide label is both protective and usable.

What the records show

In a May 12, 2025, meeting, EPA staff presented Bayer with alternatives for limiting dicamba’s volatility and controlling runoff. The agency’s slide deck ended key sections by requesting a registrant response on which options should move forward.

Eight days later, Bayer told EPA it favored “Option 1” for volatility controls and “Option 3” for runoff and erosion. The company’s written response said the choices could produce a workable label for growers and cited company studies indicating that added volatility-reduction agents sharply reduced airborne dicamba. Bayer also reported large declines in off-target inquiries since 2017, figures that were not independently verified in the correspondence.

The resulting framework permits applications when temperatures are expected to reach between 85 and 95 degrees Fahrenheit, but only on half of untreated acreage at a time, with a two-day wait before the remainder can be sprayed. Applications are prohibited when temperatures will reach 95 degrees or higher. The approach is less restrictive than an alternative that would have stopped applications above 85 degrees.

EPA defends the process

EPA told The Guardian that manufacturers may propose ways to preserve a product’s utility, while the agency independently develops mitigations and retains final authority. It called the exchange evidence that the regulatory process was working as designed, not a compliance failure.

The agency’s public decision page describes the February 2026 approval as limited to two growing seasons and says it imposes the strongest dicamba protections in EPA history. Beyond temperature restrictions, the rules cut the annual application limit from two pounds to one pound per acre, limit farmers to two applications per season, double the required volatility-reduction agent and establish a 240-foot downwind buffer.

The labels also require conservation practices to control runoff, restrict spraying before expected rain and during certain wind conditions, prohibit aerial application and require certified applicators to complete annual training. EPA says it will review incident reports, environmental data and compliance after the 2026 and 2027 seasons, and can tighten or revoke the approvals if the safeguards fail.

Why dicamba remains disputed

Dicamba kills broadleaf weeds without harming crops genetically engineered to tolerate it, making it valuable against Palmer amaranth and other weeds resistant to older herbicides. The American Soybean Association supported the February approval, saying stable rules would help farmers plan and protect yields, according to AP coverage.

The same chemical can move beyond a treated field through spray drift, vaporization after application or runoff. EPA acknowledges that past use damaged neighboring crops, sensitive plants and wildlife habitat. Environmental groups argue that buffers and label instructions have repeatedly failed to prevent widespread injury, particularly during hot weather when volatility increases.

Courts have twice vacated registrations for over-the-top dicamba use. A 2020 appeals court found that EPA had substantially understated risks, and a federal judge in 2024 ruled that the agency had bypassed required public-comment procedures. When EPA proposed the latest registrations in July 2025, Reuters reported that the agency found no significant human-health risk under labeled uses but did identify risks to some plants.

The policy question

Federal pesticide law necessarily requires technical exchanges with manufacturers, which hold product-specific studies and must produce labels that applicators can follow. The policy issue raised by the records is not whether EPA should hear from Bayer. It is whether the agency sufficiently separated the company’s commercial preferences from its own independent judgment, documented that analysis and gave outside experts a meaningful chance to test the result.

That distinction matters because registration labels allocate risk among parties with different leverage. The manufacturer gains access to a major market, growers gain another weed-control option, and neighboring farms or conservation areas may bear damage if the restrictions prove inadequate. Transparent reasoning is therefore part of the safeguard, not merely an administrative formality.

The newly released correspondence will likely become evidence in ongoing litigation brought by the Center for Biological Diversity and Center for Food Safety. It may also sharpen congressional questions about transparency inside EPA’s Office of Chemical Safety and Pollution Prevention, particularly when regulators choose among safeguards with materially different levels of protection.

For growers, the immediate legal requirements have not changed: the 2026 labels remain enforceable, and the approvals extend through the 2027 season unless EPA or a court intervenes. For the agency, the harder test will be whether real-world monitoring validates the compromise. A process can include industry consultation without surrendering regulatory judgment, but the record must show where consultation ended and independent decision-making began.