Action of the Week Archive

We have advocated against the use of the weed killer atrazine, and now the U.S. Environmental Protection Agency (EPA) is officially taking comments on whether to issue new restrictions on the chemical's use. As we know, EPA received accolades for its August 7, 2024, decision to ban the weed killer Dacthal (or DCPA--dimethyl tetrachloroterephthalate), leaving many people asking, “Why Dacthal and not other very hazardous pesticides?” The weed killer atrazine (in the triazine chemical family) poses similar elevated hazards to people and the environment, has proven to be impossible to contain, and has viable alternatives. Therefore, we need to challenge EPA to apply the same standard that removed Dacthal from the market to the long list of pesticides that are contributing to a health crisis, biodiversity collapse, and the climate emergency. 

In its current proposal, EPA is choosing to downplay atrazine's risk to ecosystems, allow more contamination with the herbicide, and apply a wishy-washy, ineffective enforcement mechanism. In reevaluating the risk to aquatic systems, EPA has chosen to exclude four of the six experiments that it previously judged to show an effect on aquatic plant communities, which allowed it to increase the allowed concentration of atrazine in surface water from 3.4 ug/L to 9.7 ug/L. If atrazine concentrations exceed that allowed concentration, they will trigger mitigation measures. 

Mitigation is to follow EPA's “herbicide mitigation strategy,” which provides a menu of options providing “flexibility” to pesticide applicators, with no incentive to adopt more ecologically-based approaches such as organic farming and land management. 

EPA is accepting comments on its proposal until February 18, 2025, through Regulations.gov.  

>> EPA must apply the standard of the Dacthal decision to atrazine and issue an emergency suspension and prohibit the use of existing stocks. 

Exposure to atrazine, manufactured by Syngenta, is widespread in the environment. According to EPA, “Pesticide products containing atrazine are registered for use on several agricultural crops, [including] field corn, sweet corn, sorghum, and sugarcane, []wheat, macadamia nuts, and guava, as well as non-agricultural uses such as nursery/ornamental and turf.” It is the second most widely used herbicide in the U.S. after glyphosate (found in Roundup), but banned in the European Union in 2004 and over 40 countries worldwide. Many organizations have called for the chemical to be banned in the U.S. and have joined in litigation against EPA. 

In the case of Dacthal, EPA used the “imminent hazard” clause of the federal pesticide law to immediately suspend the chemical's use. At the same time, the agency is exercising its authority to prohibit the continued use of Dacthal's existing stocks, a power that EPA rarely uses. The last time EPA issued an emergency action like this was in 1979 when the agency acknowledged miscarriages associated with the forestry use of the herbicide 2,4,5-T—one-half of the chemical weed killer Agent Orange, sprayed over people to defoliate the landscape of Vietnam in the war there—with the most potent form of dioxin, TCDD (2,3,7,8-Tetrachlorodibenzo-p-dioxin). The chemical manufacturer of Dacthal, AMVAC Chemical Corporation, can challenge the agency's findings under the law and seek court review, but EPA's action takes effect immediately while any appeal is considered. Meanwhile, EPA has stopped use under 7 U.S.C. 136 et seq., pursuant to section 6(c)(3) (7 U.S.C. 136d(c)(3)). (See Unit IV.) The prohibition on the use of existing stocks is mandated under Section 6(a)(1). 

The timeline for review and action on individual pesticides has taken decades since the 1972 overhaul of nation's pesticide law, the Federal Insecticide, Fungicide and Rodenticide Act (FIFRA). The law's risk-benefit standard allows for high levels of harm, especially to farmworkers and those handling pesticides, as well as public exposure through residues in food, water, and air. EPA's decisions are based on agency risk assessments that use flawed assumptions and ignore vulnerable populations like children and those with preexisting health conditions—like cancer, endocrine system disruption, neurological illness, and other health effects that are exacerbated by exposure. Amendments to FIFRA in 1996, in the Food Quality Protection Act (FQPA), have done little to reduce the ongoing reliance on toxic chemicals in food production and land management, despite the growth of the $70 billion organic industry—still not considered by EPA as a legitimate alternative to be evaluated when determining the “reasonableness” or “acceptability” of risk under pesticide law. Instead, EPA calculates acceptability of risk in the context of available alternative chemicals. In its press release on the Dacthal decision, EPA said, “In deciding whether to issue today's Emergency Order, EPA consulted with the U.S. Department of Agriculture to understand how growers use DCPA and alternatives to this pesticide.” The agency's consultation with USDA evaluated alternative chemicals, not alternative organic management systems and organic-compatible substances. 

The current mechanism that EPA uses to restrict pesticides—negotiated settlements instead of regulatory action—compromises the health of people and the environment, often disproportionately for people of color and workers, who are the first to be exposed as applicators or agricultural workers. Could the Dacthal decision be a watershed moment to change a regulatory process that allows daily pesticide exposure, poisoning, and contamination at rates that EPA deems acceptable—despite the overwhelming science linking real-world pesticide use (from homes to parks and playing fields, schools, and farms) to dreaded illnesses, biodiversity collapse, and the climate crisis? See Pesticide-Induced Diseases Database and the Pesticide Gateway. 

In making its decision to ban Dacthal, EPA states that it considered: 

1. The seriousness of the threatened harm; 

2. The immediacy of the threatened harm; 

3. The probability that the threatened harm will occur; 

4. The benefits to the public of the continued use of the pesticide; and 

5. The nature and extent of the information before the Agency at the time it makes a decision. 

These criteria could be met for most of the pesticides for which EPA has negotiated settlements with pesticide manufacturers, resulting in partial withdrawals of pesticides from the market and compromises that threaten health and the environment. 

Based on the reasoning in the Dacthal decision, EPA should ban atrazine. 

Atrazine poses immediate serious harms to people and the environment. 
Registration of the endocrine-disrupting herbicide propazine (in the triazine family of frog-deforming endocrine disruptors) was canceled by EPA, eliminating the use of the hazardous herbicide by the end of 2022. However, all pesticides in the triazine class, including atrazine and simazine, have similar properties and should be eliminated from use.

Under an Endangered Species Act review, initiated by EPA only after a lawsuit from health and environmental groups, the triazine chemicals were found to adversely affect a range of species. Propazine was found to harm 64 endangered species, while simazine and atrazine were both likely to harm over 50% of all endangered species and 40% of their critical habitats. EPA finds, “aquatic plant communities are impacted in many areas where atrazine use is heaviest, and there is a potential chronic risk to fish, amphibians, and aquatic invertebrates.” In addition, evidence shows that subsequent life stages or generations of fish are at greater risk of reproductive dysfunction after embryonic/early life exposure to atrazine. 

The triazine class of chemicals also pose significant threats to human health and are particularly concerning in the context of the range of chemicals one may be exposed to in today's world. As Tyrone Hayes, PhD, University of California, Berkeley professor, noted at a presentation at Beyond Pesticides' National Pesticide Forum, “Children in utero may be exposed to over 300 synthetic chemicals before they leave the womb… I would argue that a human fetus trapped in contaminated amniotic fluid is no different than one of my tadpoles trapped in a contaminated pond.”  

Atrazine has been linked to a range of adverse birth outcomes, including smaller body sizes, slower growth rates, and certain deformities like choanal atresia (where nasal passages are blocked at birth), and hypospadias (where the opening of a male's urethra is not located at the tip of the penis). The mechanism of toxicity is perturbation of the neuroendocrine system by disrupting hypothalamic regulation of the pituitary, leading primarily to a disturbance in the ovulatory surge of luteinizing hormone (LH), which results in both reproductive and developmental alterations. Of the numerous adverse effects associated with this disruption, the two that appear to be the most sensitive and occur after the shortest duration (4 days) of exposure are the disruption of the ovarian cycles and the delays in puberty onset.

Despite these endocrine-disrupting effects, EPA reduces the margin of safety and underestimates exposure to children. 

Mitigation measures have not eliminated the harm. 
In November 2020, Beyond Pesticides and allied environmental groups launched a lawsuit against EPA for its intent to reregister the triazine family of chemicals. The agency's interim approval of the herbicides, conducted under the Trump administration, eliminates important safeguards for children's health and a monitoring program intended to protect groundwater from contamination. As is typical with EPA, the agency merely proposed minor label changes in attempts to mitigate risks identified in its registration review. According to a release from EPA, it made the decision not out of concerns relating to human health and environmental protection, but in order to provide “regulatory certainty” for farmers and local officials. 

Although a hefty 200,000 lbs. of propazine were used each year, mainly on sorghum in Texas, Oklahoma, and Kansas, this amount pales in comparison to the over 70 million lbs. of atrazine used throughout the United States. Under an Endangered Species Act review, initiated by EPA only after a lawsuit from health and environmental groups, the triazine chemicals were found to adversely affect a range of species. Propazine was found to harm 64 endangered species, while simazine and atrazine were both likely to harm over 50% of all endangered species and 40% of their critical habitats. 

The public does not benefit from continued registration of atrazine. 
While industry consistently lines up local Congressmembers, former EPA officials, and agrichemical lobbyists to pressure EPA to keep triazines in the market, there is no evidence that the herbicides benefit the farmers these officials claim to represent. According to research published in the International Journal of Occupational and Environmental Health, banning atrazine would provide an economic benefit to farmers. “The winners,” the research concludes, “in an atrazine free future would include farm workers, farmers and their families, and others who are exposed to atrazine either directly from field uses or indirectly from contaminated tap water along with natural ecosystem that are currently damaged by atrazine.”  

EPA has sufficient information to cancel atrazine. 
EPA has long known about triazine's threats to wildlife, including its ability to chemically castrate male frogs. However, the agency has consistently defended the chemical and sat by while independent researchers like Dr. Hayes, who conducted seminal research on atrazine's endocrine-disrupting properties, are pilloried by chemical industry propaganda. In a Critical Perspectives piece published in Environmental Toxicology and Chemistry, Jason Rohr, PhD, provides an in-depth investigation of the atrazine controversy. 

“I argue that the atrazine controversy must be more than just a true story of cover-ups, bias, and vengeance,” he writes in the piece. “It must be used as an example of how manufacturing uncertainty and bending science can be exploited to delay undesired regulatory decisions and how greed and conflicts of interest—situations where personal or organizational considerations have compromised or biased professional judgment and objectivity—can affect environmental and public health and erode trust in the discipline of toxicology, science in general, and the honorable functioning of societies.” 

The Draft Ecological Risk Assessments for the Registration Review of Atrazine, Simazine, and Propazine dated October 5, 2016, found high risks that were supported by EPA's assessments. EPA states, “Based on the results from hundreds of toxicity studies on the effects of atrazine on plants and animals, over 20 years of surface water monitoring data, and higher tier aquatic exposure models, this risk assessment concludes that aquatic plant communities are impacted in many areas where atrazine use is heaviest, and there is potential chronic risk to fish, amphibians, and aquatic invertebrates in these same locations. In the terrestrial environment, there are risk concerns for mammals, birds, reptiles, plants and plant communities across the country for many of the atrazine uses. EPA levels of concern for chronic risk are exceeded by as much as 22, 198, and 62 times for birds, mammals, and fish, respectively. For aquatic phase [stage] amphibians, a weight of evidence analysis concluded there is potential for chronic risks to amphibians based on multiple effects endpoint concentrations compared to measured and predicted surface water concentrations. The breadth of terrestrial plant species and families potentially impacted by atrazine use at current labeled rates, as well as reduced rates of 0.5 and 0.25 lbs. a.i./A, suggest that terrestrial plant biodiversity and communities are likely to be impacted from off-field exposures via runoff and spray drift. Average atrazine concentrations in water at or above 5 μg/L for several weeks are predicted to lead to reproductive effects in fish, while a 60-day average of 3.4 μg/L has a high probability of impacting aquatic plant community primary productivity, structure, and function.”  

The agency acknowledges many risks of concern associated with the uses of atrazine but asserts the remaining serious worker and ecological risks after the adoption of all proposed mitigation measures are outweighed by the benefits of atrazine use. EPA has determined that the chlorotriazines (triazines) and their three chlorinated metabolites share a common mechanism of toxicity, and as such, human health risks were assessed together through a triazine cumulative risk assessment. The mechanism of toxicity is perturbation of the neuroendocrine system by disrupting hypothalamic regulation of the pituitary, leading primarily to a disturbance in the ovulatory surge of luteinizing hormone (LH), which results in both reproductive and developmental alterations. Of the numerous adverse effects associated with this disruption, the two that appear to be the most sensitive and occur after the shortest duration (4 days) of exposure are the disruption of the ovarian cycles and the delays in puberty onset. Importantly, this perturbation manifests after short duration exposure with long-term life-cycle consequences, so it establishes both acute and chronic toxicity levels of concern (LOCs). 

Toxicity and exposure data available to EPA are sufficient to demonstrate that several atrazine uses exceed risk levels of concern. Exposures to children 1-2 years old playing on turf sprayed with atrazine exceed a risk estimate of concern for combined dermal and incidental oral exposures when assuming the maximum labeled rate for spray applications (2.0 lb ai/A). However, a screening aggregate assessment without the FQPA required safety factor was performed assuming that the application rate for turf is reduced to 1.0 lb ai/A, which would not be of concern for 4-day aggregate exposures. Even with this rate reduction, it can be presumed children are still at serious risk. For occupational handlers, EPA identified use scenarios that exceed risk concerns even with the maximum available personal protective equipment and/or engineering controls (proposed mitigation measures). 

Here is how EPA describes its truncated process for DCPA: 

In 2013, the agency issued a Data Call-In (DCI) to AMVAC Chemical Corporation, the sole manufacturer of DCPA, requiring it to submit more than 20 studies to support the existing registrations of DCPA. The required data included a comprehensive study of the effects of DCPA on thyroid development and function in adults and in developing young before and after birth, which was due by January 2016. Several of the studies that AMVAC submitted from 2013-2021 were considered insufficient to address the DCI, while the thyroid study and other studies were not submitted at all. 

In April 2022, EPA issued a very rarely used Notice of Intent to Suspend the DCPA technical-grade product (used to manufacture end-use products) based on AMVAC's failure to submit the complete set of required data for almost 10 years, including the thyroid study. While AMVAC submitted the required thyroid study in August 2022, EPA suspended the registration based solely on AMVAC's continued failure to submit other outstanding data on Aug. 22, 2023, following an administrative hearing.  In November 2023, the data submission suspension was lifted after AMVAC submitted sufficient data. Most DCPA use on turf was voluntarily canceled by AMVAC in December 2023, but unacceptable risks from other uses remained. 

As society and the global community struggle with petrochemical pesticides and their contribution to health threats, biodiversity collapse, and the climate emergency, EPA must acknowledge that Dacthal is one active ingredient among over 1,000 in 56,000 pesticide products whose uses can be eliminated by the use of organic systems that have now been shown to be effective.  

>> EPA must apply the standard of the Dacthal decision to atrazine and issue an emergency suspension and prohibit use of existing stocks. 

For more information on the dangers of atrazine and its chemical cousins, read Beyond Pesticides comments to EPA, and watch Tyrone Hayes, PhD presentations from former National Pesticide Forum events on YouTube.

By 2032, all petrochemical pesticides must be phased out and replaced by organic systems and substances compatible with the protection of health and the environment and a livable future. 

The target for this Action is the U.S. Environmental Protection Agency, via comments through Regulations.gov.

Thank you for your active participation! The Action is a multi-step process, so please click submit below to proceed to step two, where you will be able to personalize comments before final submission. The comment maximum limit is 4,000 characters, so it may be necessary to delete some of our prepared message text if editing.