01
Oct
Beyond Pesticides Urges Ban of Weed Killer Paraquat Using Same Criteria Used in the Landmark Dacthal Ban
(Beyond Pesticides, October 1, 2024) 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, Beyond Pesticides is challenging 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, Beyond Pesticides says.
EPA must apply the standard of the Dacthal decision to paraquat and issue an emergency suspension and prohibit use of existing stocks.
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 bill’s passage 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 it 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. Another 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).
EPA must apply the standard of the Dacthal decision to paraquat and issue an emergency suspension and prohibit use of existing stocks.
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 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 re: 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: “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.
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 urges the expansion and strengthening of organic land management principles to move beyond the existing product substitution framework, or pesticide treadmill, that leads to the continuous use of toxic pesticides.
EPA Administrator Michal Regan
I am pleased to see EPA’s action to ban Dacthal and prohibit the use of existing stocks. Now, I respectfully request that EPA apply the same criteria to paraquat and stop its use.
In deciding to ban Dacthal, EPA says it considered the seriousness, immediacy, and likelihood of the threatened harm; benefits to the public of continued use; and nature and extent of the information before EPA.
Please apply the three following criteria to paraquat, the three factors used to ban Dacthal.
- Paraquat poses immediate serious harms to people and the environment.
The 6th edition of Recognition and Management of Pesticide Poisonings by James R. Roberts, M.D., M.P.H, and J. Routt Reigart, M.D., says, “[P]araquat 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, . . .[p]ulmonary 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.”
Paraquat poses risks to endangered/threatened species and potential jeopardy to their continued existence. It is an endocrine disruptor. Use of paraquat is significantly associated with hypothyroidism. It 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. Moreover, the endocrine disruption activity of paraquat that causes excessive reactive oxygen species production also links it to Parkinson’s Disease.
- Mitigation measures have not eliminated harm.
EPA has downplayed the connection between exposure to paraquat and the development of Parkinson’s disease in registration review documents released by the agency, leading numerous legislators to call for the banning of paraquat.
- The public does not benefit from continued use.
Alternative pest management practices that incorporate cultural practices and/or less toxic products are available. Significantly, EPA routinely refuses to recognize the success of organic farming, which does not depend on synthetic pesticides, in calculating “benefits.”
EPA has sufficient information to ban paraquat. EPA has the information above, which is in the open literature and/or provided in regulatory comments, demonstrating that the agency has a statutory duty to revoke all registrations of the paraquat under its unreasonable adverse effects standard in FIFRA.
Please apply the standard of the Dacthal decision to paraquat. Issue an emergency suspension and prohibit use of existing stocks.
Thank you.
Members of Congress
I am pleased to see EPA’s action to ban Dacthal and prohibit the use of existing stocks. However, paraquat fits the criteria used to ban Dacthal. All of this is known to EPA.
In deciding to ban Dacthal, EPA says it considered the seriousness, immediacy, and likelihood of the threatened harm; benefits to the public of continued use; and nature and extent of the information before EPA.
- Paraquat poses immediate serious harms to people and the environment.
The 6th edition of Recognition and Management of Pesticide Poisonings by James R. Roberts, M.D., M.P.H, and J. Routt Reigart, M.D., says, “[P]araquat 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, . . .[p]ulmonary 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.”
Paraquat poses risks to endangered/threatened species and potential jeopardy to their continued existence. It is an endocrine disruptor. Use of paraquat is significantly associated with hypothyroidism. It 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. Moreover, the endocrine disruption activity of paraquat that causes excessive reactive oxygen species production also links it to Parkinson’s Disease.
- Mitigation measures have not eliminated harm.
EPA has downplayed the connection between exposure to paraquat and the development of Parkinson’s disease in registration review documents released by the agency, leading California Assemblymember Laura Friedman (D-Burbank), chair of the bicameral Environmental Caucus, to introduce legislation to phase out and ban the use of paraquat across all uses, including agriculture, by the end of 2025.
- The public does not benefit from continued use of paraquat.
Alternative pest management practices that incorporate cultural practices and/or less toxic products are available. Significantly, EPA routinely refuses to recognize the success of organic farming, which does not depend on synthetic pesticides, in calculating “benefits.”
EPA has sufficient information to ban paraquat. EPA has the information above, which is in the open literature and/or provided in regulatory comments, demonstrating that the agency has a statutory duty to revoke all registrations of the paraquat under its unreasonable adverse effects standard in FIFRA.
Tell EPA to apply the standard of the Dacthal decision consistently—to ban paraquat.
Thank you.
