10/25/2026
A brand new w**d killer is now approved in the US for wheat, field corn, soybeans and canola. In EPA's own review, young rats in a reproduction study reached puberty later, and male mice got liver tumors. EPA says it found no human health risks of concern. It's called epyrifenacil.
What happened: in late June 2026, EPA approved the first US registrations for epyrifenacil, a new w**d killer from Valent U.S.A. marketed as Rapidicil. Its first two products are called Empera and Empera Viragess. On June 30, 2026, EPA published a rule that set legal limits for leftover residue of 0.005 parts per million (ppm) in wheat grain, corn grain, soybean seed and canola (rapeseed) seed. A correction on July 28, 2026 set the limit at 0.01 ppm for animal feed such as forage, hay and straw. It is a "burndown" w**d killer, which means it is sprayed on fields to kill w**ds before the crop comes up (before planting, or for soybeans up to 3 days after planting). Valent says it will be available in late 2026. It is new to the US. Sumitomo Chemical, Valent's parent company, says the US is the fourth country to register it, after Argentina in 2024 and other countries.
What EPA found in animal studies: in the rule, EPA says "Reproductive toxicity included delayed sexual maturation in F1 males and females." In plain words, the pups born to the dosed parent rats (called F1) reached sexual maturity (puberty) later than normal. EPA also lists "severely decreased red blood cell parameters indicative of anemia" in the young rats in that study, meaning low red blood cells. In mice, EPA's risk assessment reports "treatment related liver tumors (combined hepatic adenomas and carcinomas) in male mice." Adenomas are benign tumors (not cancer). Carcinomas are cancer.
To be fair: these were lab animal studies, not people. EPA says the effects on the pups "occurred in the presence of parental toxicity," meaning the doses also harmed the parent rats. EPA also noted the pups were hit harder than their parents at that dose, with deaths in F1 males and none in the parents. EPA classified epyrifenacil as "not likely to be carcinogenic to humans below doses that induce hepatocellular injury," meaning EPA expects no cancer risk for people below the dose that starts to injure the liver, and the mouse tumors appeared at doses above that. EPA estimated that babies, the most exposed group, would get up to 53% of the daily amount EPA considers safe over a lifetime from food and water, and the general public 16%, assuming every acre is treated and residues sit at the legal limit. In its final registration decision, EPA says it "has not identified any dietary, aggregate, non-occupational or occupational risks of concern" for potential human health exposure. EPA concluded there is "a reasonable certainty that no harm will result" to the general population, or to infants and children. The Center for Biological Diversity calls it a PFAS, or "forever chemical," pesticide. EPA disputes that. It says this pesticide has a single fluorinated carbon, so it is not PFAS under the current federal definition. The broader international (OECD) definition counts any chemical with a CF3 group, a carbon with three fluorine atoms, and this one has one.
What you can do: USDA organic rules do not allow synthetic w**d killers unless they are on an approved list, and epyrifenacil is not on it, so organic farms cannot spray it. To lower your chances of eating it, you can choose USDA certified organic wheat, corn and soy foods, such as flour, cornmeal, tortillas and tofu.
Sources: Federal Register, EPA final rule "Epyrifenacil; Pesticide Tolerances," June 30, 2026 (91 FR 39512, document 2026-13193), and correction, July 28, 2026 (document 2026-15191). EPA docket EPA-HQ-OPP-2022-0354: human health risk assessment and final registration decision. Valent U.S.A. news release, July 2, 2026. Sumitomo Chemical news release, July 2, 2026. Center for Biological Diversity, June 30, 2026. Newsweek, July 6, 2026 (EPA statement). EPA, "FACT CHECK: EPA Debunks False Claims that Agency Recently Approved 'Forever Chemical' Pesticides," November 26, 2025. OECD, 2021 PFAS definition. 7 CFR 205.105 and 205.601.