***Due to the importance of the Dacthal decision, we are providing an extended analysis below for those who wish to delve deep into the issue. To skip to the Action form, please click here or on the "Action links" (>>) below!
While the Environmental Protection Agency (EPA) received accolades for its August 7, 2024, decision to ban the herbicide Dacthal (or DCPA—dimethyl tetrachloroterephthalate), it also leaves many people asking, “Why Dacthal and not other very hazardous pesticides?” Paraquat, for example, poses similar elevated hazards to people and the environment, has no antidote, 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 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. Additionally, the agency, in coordination with the U.S. Department of Agriculture, found that there were alternatives to Dacthal.
Based on the reasoning in the Dacthal decision, EPA should ban paraquat. More background on the Dacthal decision and history of pesticide law that supports the immediate cancellation of paraquat is provided toward the end of this Action.
1. Paraquat poses immediate serious harms to people and the environment. [First factor used in Dacthal decision]
Citing serious health issues associated with its use, including Parkinson's disease, and inaction by EPA, a number of legislative efforts have been undertaken to ban paraquat. A bill in California, originally introduced as a ban bill (AB 1963), was amended to require state review and passed in August. According to the California Legislative Information website, the legislation “[r]equires, on or before January 1, 2029, the Department of Pesticide Regulation (DPR) to complete a reevaluation of paraquat dichloride (paraquat), and make the determination to retain, cancel, or suspend its registration, or to place new appropriate restrictions on the use of paraquat.” The passage of this bill follows a long history of scientific documentation of the pesticide's hazards, fits and starts in the regulatory process, and previous efforts to ban the herbicide through legislative action. In 2018, U.S. Representative Nydia Velasquez (D-NY) introduced legislation (Protect Against Paraquat Act) to ban paraquat. Paraquat was banned in the European Union in 2007, following its prohibition years earlier in 13 countries, including Sweden, Denmark, and Austria. Now, over 60 countries have banned the use, production, and sale of paraquat, including China, where the pesticide was first developed.
The 6th edition of Recognition and Management of Pesticide Poisonings by James R. Roberts, M.D., MPH, and J. Routt Reigart, M.D., says, “When a toxic dose is ingested (see below), paraquat has life-threatening effects on the gastrointestinal tract, kidney, liver, heart and other organs. The LD50 in humans is approximately 3-5 mg/kg, which translates into as little as 10-15 mL of a 20% solution... Although pulmonary toxicity occurs later in paraquat poisoning than other manifestations, it is the most severe and, therefore, mentioned first. Pulmonary effects represent the most lethal and least treatable manifestation of toxicity from this agent. The primary mechanism is through the generation of free radicals with oxidative damage to lung tissue. While acute pulmonary edema and early lung damage may occur within a few hours of severe acute exposures, the delayed toxic damage of pulmonary fibrosis, the usual cause of death, most commonly occurs 7-14 days after the ingestion. In those patients who ingest a very large amount of concentrated solution (20%), some have died more rapidly from circulatory failure (within 48 hours) prior to the onset of pulmonary fibrosis.”
A 2005 study in Toxicological Sciences was able to “reproduce features of Parkinson's disease (PD) in experimental animals.” Studies continued to replicate findings associating paraquat with Parkinson's disease, as EPA continued to reject the need for action.
In the U.S., paraquat is currently a restricted-use pesticide (meaning it can only be applied by certified applicators or those working under their on- or off-site supervision) and banned on golf courses. There is established and mounting evidence of links between minimal exposure and various adverse health impacts for humans and wildlife.
Beyond Pesticides continues to track the latest scientific literature on adverse health impacts of paraquat. Within all the single-pollutant models employed in a 2022 study published in Journal of Clinical Endocrinology and Metabolism, researchers found a linkage between paraquat dichloride and thyroid cancer. A different study published that same year in Independent determined the toxic impacts of paraquat on bird embryos, including the Japanese quail, mallards, bobwhite quail, and ring-necked pheasant.
EPA's ecological risk assessment in support of its ID did not consider risks to endangered/threatened species and potential jeopardy to their continued existence. As stated in the assessment: “Given that the agencies are continuing to develop and work toward implementation of the Interim Approaches to assess the potential risks of pesticides to listed species and their designated critical habitat, this ecological risk assessment for paraquat does not contain a complete ESA analysis that includes effects determinations for specific listed species or designated critical habitat.” Considering that the calculated risk quotients (RQs) exceed established levels of concern (LOCs) for most unlisted species, it can be inferred that listed plant and animal species in areas of paraquat use could indisputably be at risk of jeopardy.
Paraquat has also not been fully assessed by EPA for potential endocrine disruption. Both the human health and ecological assessments deferred an assessment and provided canned language that endocrine disrupting potential will be further considered under the Endocrine Disruptor Screening Program (EDSP). However, there is evidence available that paraquat has endocrine disrupting effects. Use of paraquat is significantly associated with hypothyroidism. Paraquat has been reported to decrease testosterone, follicle-stimulating hormone, luteinizing hormone and prolactin in male rats. In the frog Rana esculenta, paraquat was found to inhibit the production of testosterone in the testis and 17-beta-estradiol in the ovary. More importantly, the endocrine disruption activity of paraquat that causes excessive reactive oxygen species production also links paraquat to Parkinson's Disease. Though somewhat limited, these data do indicate a potential for unreasonable adverse endocrine disruption in humans and wildlife and should be further investigated as mandated in the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) and the Food Quality Protection Act (FQPA).
2. Mitigation measures have not eliminated the harm. [Second factor used in Dacthal decision]
In 2018, EPA downplayed the connection between exposure to paraquat and the development of Parkinson's disease in registration review documents released by the agency. But California Assemblymember Friedman, the prime sponsor of AB1963 (cited above), in a press release on the day the California legislation was introduced, said, “We cannot afford to ignore decades of mounting evidence linking paraquat exposure to Parkinson's disease, non-Hodgkin lymphoma, and childhood leukemia.” She continued: “In 2021, the latest year for which data are publicly available, just over 430,000 pounds were applied in California, primarily in Kern, Kings, Fresno, Merced, and Tulare counties. The herbicide is extremely toxic to humans, with low doses causing death, and it has been linked to increased risk of Parkinson's Disease.”
EPA's actions, or inaction as some would argue, on the scientific literature on paraquat exposure and Parkinson's disease represent a failure of EPA to take a proactive approach in ending the continued exposure and health impacts of the toxic herbicide to chemically sensitive populations. According to the EPA's Office of Pesticide Programs' guidelines on paraquat and diquat, these ammonium herbicides are life-threatening in toxic doses and hold the potential to “impact GI tract, kidney, lungs liver, heart, and other organs.” Specifically regarding paraquat, “pulmonary fibrosis is the usual cause of death in paraquat poisoning.”
In 2019, EPA released, “Systematic Review of the Literature to Evaluate the Relationship between Paraquat Dichloride Exposure and Parkinson's Disease.” Following this ruling, EPA was lambasted for its dismissal of the linkage between Paraquat exposure and Parkinson's Disease, despite a growing body of literature between 2009 and 2019 and, given that “[a]n EPA environmental review conducted as part of the reregistration process found evidence of significant reproductive harm to small mammals, and determined that songbirds may be exposed to levels well beyond lethal concentrations known to cause death. Threats to mammals and songbirds are particularly concerning considering significant declines in these animal groups.”
In 2019, Beyond Pesticides submitted comments and concluded: “Since the agency risk assessments are intended to support Agency risk management review, risk management recommendations are not provided in its draft risk assessments. The many risk concerns and uncertainties (lack of data) identified in both the human health and ecological risk assessments makes it unconscionable to allow continued use of such a dangerous pesticide as paraquat. A restricted use label will do little to allay the ecological risk concerns enumerated or adequately protect persons in vicinity of treatments or in harvest and post-harvest activities. Taken together with the clear inability of the agency to preclude potential for Parkinson's disease, it is recommended that the use of paraquat should be immediately suspended if not outright cancelled as it is in the EU and several other countries.”
In late January 2024, EPA released a report, “Preliminary Supplemental Consideration of Certain Issues in Support of its Interim Registration Review Decision for Paraquat.” According to the interim report, “The Agency prepared several documents to support its 2021 interim registration review decision for paraquat and attempted 'to connect the dots' of the risk-benefit information contained in its support documents in the Paraquat ID.” The results of this interim report, specifically regarding linkage to Parkinson's disease and other health risks associated with chronic exposure to paraquat, highlight the flaws in EPA's approach to risk assessment and opportunities to incorporate additional sources of sound science in the final report in January 2025. For example, “EPA intends to consider [additional studies] as part of the next steps in this process. First, EPA recognizes that the Michael J. Fox Foundation and Earthjustice submitted letters to EPA on August 4, 2023, along with information that they believe is relevant to EPA's consideration of paraquat's health risks. This information consisted of approximately 90 submissions including scientific studies, as well as testimony filed in an ongoing state lawsuit concerning paraquat. EPA has included these documents in the docket for paraquat at EPA-HQ-OPP-2011-0855-0317 and EPA-HQ-OPP2011-0855-0313. While the Agency has started reviewing that material, it was unable to complete that review prior to the issuance of this document. [As a result, this document does not reflect the Agency's review of any of those materials.] Second, new information on paraquat vapor pressure was submitted on January 18, 2024, which may impact the Agency's volatilization analysis. Due to the late submission of that data, EPA has not incorporated that information into this document. Therefore, EPA intends to address that material along with any other significant information it receives during the public comment period and incorporate its consideration of those materials into any final document(s) issued by January 17, 2025.” Advocates found it surprising that the EPA was not able to review studies submitted by the Michael J. Fox Foundation and Earthjustice even though the agency had more than several months for review. Beyond Pesticides will continue to track updates to this upcoming public comment period to insert new studies and data points for EPA to include in their final report.
In April 2024, Beyond Pesticides' comments on the Paraquat Interim Registration Review stated, “EPA failed to assess a common mechanism of toxicity for PQ [paraquat] and any other substance in its review for the ID [interim decision], erroneously concluding that PQ does not have a common mechanism of toxicity or combined toxic action with other substances that may interact and potentiate its action.” The comments address the mandates under FIFRA and FQPA, stating that the agency failed to meet its mandate to obtain proof that paraquat “unequivocally does not cause or contribute to Parkinson's disease” and to assess paraquat endocrinological risk through FQPA's EDSP, respectively. Additionally, the comments cite EPA's failure to adequately review and incorporate the breadth of studies pointing to a relationship between Parkinson's disease and paraquat exposure; failure within its ecological risk assessment to consider risks to endangered wildlife and subsequent ecosystem balance concerns; and failure in its risk-benefit analysis to fully consider the risks of paraquat exposure.
3. The public does not benefit from continued registration of paraquat. [Third factor used in Dacthal decision]
Although EPA asserts that there are no direct alternatives to paraquat, several alternatives, chemical and nonchemical, are widely available. Given the availability of alternative pest management practices that incorporate alternative cultural practices and/or less toxic products, including other registered pesticides, the agency has a statutory duty to revoke all registrations of the paraquat under its unreasonable adverse effects standard in FIFRA. The risks and uncertainties identified by the agency in its assessments and the independent scientific literature are not reasonable in light of the availability of less toxic alternatives and cultural practices. To refute a rebuttable presumption against paraquat registration, the many data gaps listed before would need to be fulfilled and reveal opposing evidence to existing adverse effect data.
EPA has sufficient information to cancel paraquat.
EPA has the information above, which is in the open literature and/or provided in regulatory comments by Beyond Pesticides and others. The failed regulation, and subsequent harm, caused by paraquat is but one representation of a failed regulatory system that can and should do more to eliminate the use of toxic petrochemical-based pesticides. The convergence of crosscutting crises of health threats, biodiversity collapse, and the climate emergency stems from continued reliance on fossil fuels and petrochemical pesticides and fertilizers, which perpetuate the harms of greenhouse gas emissions. These crises are causing ecosystem fragmentation and failure, and public health crises that undermine the nutritional integrity of the food supply and the scientific integrity the public relies on for safety and well-being. After decades of working with farmworkers and farmers who face the brunt of toxic pesticide exposure, Beyond Pesticides echoes the call for advocates across the nation to expand and strengthen organic land management principles to move beyond the existing product substitution framework that leads to the continuous use of toxic pesticides.
Additional Background Information—What is the Dacthal Standard?
EPA describes its regulatory process leading to Dacthal ban as follows:
In 2013, the agency issued a Data Call-In (DCI) to AMVAC Chemical Corporation, the sole manufacturer of DCPA, [Dacthal] 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, and EPA must acknowledge that Dacthal is one active ingredient among over 1,000 in 56,000 pesticide products whose uses can be eliminated with the use of organic systems that have now been shown to be effective.
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 the nation's pesticide law, 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 (including Parkinson's disease), and other health effects that are exacerbated by exposure. Amendments to FIFRA in 1996, in 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 (homes, to parks and playing fields, schools, and farms) to dreaded illnesses, biodiversity collapse, and the climate crisis? (See the Pesticide-Induced Diseases Database and the Pesticide Gateway.)
In making its decision to ban Dacthal, EPA states that it considered:
- The seriousness of the threatened harm;
- The immediacy of the threatened harm;
- The probability that the threatened harm will occur;
- The benefits to the public of the continued use of the pesticide; and
- 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.
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.
>> EPA must apply the standard of the Dacthal decision to paraquat and issue an emergency suspension and prohibit use of existing stocks.
The targets for this Action are the U.S. Environmental Protection Agency and the U.S. Congress.
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