Environmental Groups Sue EPA Over Decades-Long Delay in Setting Water Standards for Atrazine

16 October 2026, Washington, D.C.: Three environmental and public health groups filed a federal lawsuit on October 14, 2026, against the US Environmental Protection Agency, seeking to force the agency to finally develop Clean Water Act water quality standards for atrazine, one of the most widely applied herbicides on American corn.

The suit, brought by the Center for Biological Diversity, the Pesticide Action and Agroecology Network, and the Center for Environmental Health, was filed in the US District Court for the Northern District of California. It targets the current administration and the EPA rather than any named individual official. The groups argue that the Clean Water Act requires the agency to set numeric water quality criteria for pollutants such as atrazine, a process they say the EPA began years ago but never completed, leaving the herbicide without the kind of enforceable water standard that exists for many other contaminants.

Atrazine is a widely used, inexpensive herbicide applied mainly to corn, along with sorghum and some other row crops, to control broadleaf weeds and grasses before or shortly after planting. It is also one of the most frequently detected pesticides in American rivers, streams, and drinking water supplies, particularly across the Corn Belt, because it is prone to runoff and does not break down quickly in water.

The lawsuit lands as the EPA is separately moving toward reapproving atrazine’s use for roughly two more decades under its ongoing registration review process. The plaintiffs cite an outside study estimating that the agency’s current reapproval proposal would still leave the vast majority of the most contaminated watersheds in the country at atrazine concentrations above the level the EPA itself has judged safe for aquatic life. The groups point to that gap as evidence that the registration review process alone will not protect waterways, and that separate, legally mandated water quality criteria are needed.

The press release announcing the suit also lays out a longer history of regulatory moves the groups view as weakening atrazine oversight over time: the rollback of certain Food Quality Protection Act safety precautions intended to protect children during the first Trump administration, the application of a less conservative safety margin in subsequent risk assessments, and a 2019 decision that eased aquatic-life safeguards the agency had put in place in 2006.

Nathan Donley, environmental health science director at the Center for Biological Diversity, Margaret Reeves, a senior scientist at the Pesticide Action and Agroecology Network, and Tom Fox, senior legislative counsel at the Center for Environmental Health, are named as spokespeople for the plaintiffs in the announcement. The release does not specify the exact remedy the groups are asking the court to order, beyond compelling the EPA to complete the water quality criteria process for atrazine that it says has sat unfinished for years.

The case does not immediately change how atrazine can be sold or applied. It is a procedural challenge aimed at the EPA’s rulemaking obligations rather than a direct challenge to any specific product registration, and any resulting standards would likely take further rulemaking to implement even if the plaintiffs prevail.

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