Atrazine, a hormone-disrupting herbicide banned in over 60 countries since 2003, is contaminating nearly 25% of all continental US river miles — roughly 860,000 miles — at levels harmful to wildlife and potentially dangerous to humans. A new review of federal EPA records by the Center for Biological Diversity marks the first comprehensive analysis of the contamination's scope, and the picture is grim. The affected waterways cover more than 20% of surface drinking water intakes nationwide and overlap with over 675,000 private and commercial wells. Seventy million pounds of atrazine are sprayed on US cropland annually, primarily on corn, sugarcane, and sorghum. It remains the country's second most widely used pesticide, generating an estimated $2-3 billion in US sales for chemical giant Syngenta in 2025. The health science is not ambiguous. The International Agency for Cancer Research classifies atrazine as a probable carcinogen. It is a documented endocrine disruptor linked to impaired fetal growth, pre-term birth, birth defects, lower sperm counts, poor semen quality, irregular menstrual cycles, and reduced fecundity in both sexes. In frogs, exposure at just 0.1 parts per billion causes reproductive organ damage and sex changes — the current allowable level in US drinking water is 3 ppb, thirty times higher. Researcher Tyrone Hayes, who first documented atrazine's effects on frog reproduction in the early 2000s, says there is no safe level of use. Five regional hotspots concentrate the worst contamination: the Chesapeake Bay watershed (home to 18 million people and 3,600+ species), the midwest corn belt, Florida's Lake Okeechobee, the lower Mississippi River, and the Texas Gulf coast. In the midwest corn belt — Kansas, Nebraska, Iowa, Missouri, Illinois, Indiana, Ohio — over two-thirds of river miles are contaminated, covering roughly half the region's wells and 68% of drinking-water treatment facility intakes. States in this region show rapidly rising early-onset cancer diagnoses compared to the national average. Along the lower Mississippi, concentrations exceed five times the level the EPA itself considers harmful to aquatic ecosystems. The regulatory failure is structural, not accidental. The EPA acknowledged the water pollution problem in 2020 and promised a plan. A 2024 draft reviewed by report co-author Nathan Donley was, in his words, "not worth the paper that it's printed on." The Center for Biological Diversity and other groups have sued over EPA's continued approval of atrazine, and Donley expects litigation to resume once the final plan is published. The chemical also travels atmospherically — USGS research found atrazine sprayed in Kansas raining down on Minnesota. The core dynamic is textbook regulatory capture. Syngenta's flagship product generates billions in revenue. The pesticide industry lobby behind atrazine is second only to glyphosate's. The EPA has had the data for decades and has not acted. Sixty countries assessed the same science and banned the chemical. The US did not. The result is that American consumers, farmworkers, and ecosystems bear the health and environmental costs while a single manufacturer captures the profit. Donley's summary is blunt: "We need to follow the lead of over 60 countries around the world and ban atrazine once and for all. Failing to do so will mean disease, death, and dirty water in America for decades to come." Neither the EPA nor Syngenta responded to requests for comment.
