EPA Addresses Risks Posed by Four Common Herbicides

Last week, to address ecological risks, the Environmental Protection Agency (EPA) released interim decisions (ID) for three Pyridines and Pyrimidines herbicides: clopyralid, dithiopyr, and triclopyr. Picloram, another similar herbicide, currently has a proposed interim decision (PID).

If you don’t feel like reading the entire report, read on to view a summarized (and simplified) description of what these decisions mean for applicators.

New Decisions Bring Updated Label Language & Restrictions

Pyridines and Pyrimidines are a class of herbicides used to control broadleaf weeds, woody brush, and aquatic plants in both agricultural and non-agricultural settings. Agricultural use sites include grains, fruits, vegetables and other crops. Non-agricultural use sites include turf, industrial areas, and roadsides.

The EPA is still working to address compost contamination concerns connected to these herbicides. In the meantime, they are requiring the following measures while the IDs and PIDs are under registration review: 

Clopyralid and Picloram:

  • Prohibit the transport of treated plant matter and manure from animals that recently grazed in treated areas for off site composting for a period of time until residues have adequately declined.
  • A clean-out period of at least 3 days for animals fed with treated plant materials.
  • Removal of use on residential turf language from all labels (clopyralid only).
  • For pasture and turf sites: applicators must notify landowners/operators of compost restrictions. Applicators must keep records of the notification for two years.
  • Updated compost pictogram on pesticide labels showing users when not to compost materials.
  • Registrants to participate in a stewardship program and provide educational outreach for those affected by herbicide residues in compost.

Triclopyr and Fluroxypyr:

  • Prohibit the use of treated plant materials or manure from animals that have grazed or consumed forage from treated areas for composting until 30 days after application. 
  • A clean-out period of at least 3 days for animals fed with treated plant materials.The IDs for the three herbicides mentioned above finalize enforceable mitigation measures to address spray drift risks as well as potential residues in compost. 

The compost mitigation measures also include updated label language that focuses on:

Clopyralid and Triclopyr

  • Reducing compost contamination by prohibiting off-site composting of treated plant matter and manure from grazing animals until residues have adequately declined

Clopyralid Only

  • Requiring pasture and turf applicators to notify the property owners/operators of the compost prohibition, and for the applicator to keep a record of this notification for two years
  • Requiring registrants to participate in a stewardship program and provide educational outreach for those affected by herbicide residues in compost
  • Removal of residential use on turf language from all labels

Picloram Public Comments

The PID for picloram, which proposes mitigation similar to the mitigation measures in the clopyralid ID, is currently open for public comment. Interim registration review decisions impose risk mitigation measures necessary to protect the environment pending additional assessments including an endangered species assessment. After reviewing and considering the public comments received on the proposed interim decision for picloram, the EPA will proceed with the registration review process and issue the picloram ID.

Potential Environmental & Human Health Risks 

The EPA only lists negative ecological effects as a result of Pyridines and Pyrimidines herbicides on their website. They say the ecological risks are primarily non-target terrestrial plants through spray drift and runoff. Certain herbicides in the pyridine/pyrimidine class can persist in treated plant materials, and when treated materials are recycled into compost, can cause harm to plants in gardens and ornamental plots where the compost is applied. Pathways into compost include residues in treated turf clippings, hay from treated pastures, and manure from animals that have grazed in treated areas.

Although the EPA says “there are no human health risks of concern for this class of herbicides,” the Oregon Health Authority (OHA) has different data.

According to OHA, continued exposure to drinking water that has a level of picloram above the legal limit of 500 parts per billion can cause diarrhea, weight loss, liver damage, and damage to the central nervous system.

If you have data or experience that agrees with OHA, be sure to submit your public comment on picloram here. And if you currently use any of the other three herbicides mentioned earlier, be sure to review and follow the new EPA guidelines.

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PFAS Appearing In Variety of Pesticides, EPA Responds

Over the past few months, the Public Employees for Environmental Responsibility (PEER) advocacy group has discovered that multiple publicly available herbicides and insecticides contain Polyfluoroalkyl Substances (PFAS), a group of manmade chemicals linked to various health issues.

What does all of this mean for applicators that have used these contaminated products and who might have been exposed to PFAS? Read on to get a breakdown of all of the discoveries, test findings, and possible consequences.

PFAS Background

PFAS are a group of man-made chemicals that can be found in food packaging, commercial household products, some drinking water, and more. Of the many variants, PFOA and PFOS are the most commonly produced and are known as “forever chemicals” - meaning they don’t break down or leave a person's body over time. 

The EPA recognizes that PFAS exposure can lead to “adverse health outcomes” such as low infant birth weights, effects on the immune system, cancer (PFOA), and thyroid hormone disruption (PFOS).

Contaminated Products

Per a new report from E&E News, PEER announced that their own testing revealed PFAS in the following pest control product:

  • Mavrik Perimeter - a mosquito and tick control agent Zoecon. 

Author’s Note: There are at least three other unnamed pesticides that showed PFAS levels during initial testing. PEER is still waiting for more result confirmations before putting their names out. These findings have not yet been evaluated or confirmed by the EPA. 

Anvil 10+10

The new findings listed above are part of PEER’s follow-up investigation after they discovered PFAS in a commonly used mosquito control insecticide, Anvil 10+10.

New testing from an environmental watchdog group shows PFAS are present in multiple pesticides. Claudine Hellmuth/E&E News (illustration); Freepik (mosquito); EPA (logo and text) ; Clarke Mosquito Control Products Inc. (Anvil bottle)

PEER’s initial test results revealed that it contained roughly 250 parts per trillion (ppt) of PFOA, and 260 – 500 ppt of HFPO-DA (hexafluoropropylene oxide dimer acid, a “GenX” replacement for PFOA). Massachusetts, parts of Florida, New York, and many other states have all used Anvil 10+10 in aerial spraying programs.  

When PEER alerted Massachusetts Department of Environmental Protection (MADEP) of its findings, MADEP independently tested nine samples of Anvil 10+10 from five different containers, and found eight different PFAS, including PFOA and PFOS.

“In Massachusetts, communities are struggling to remove PFAS from their drinking water supplies, while at the same time, we may be showering them with PFAS from the skies and roads,” stated PEER Science Policy Director Kyla Bennett, a scientist and attorney formerly with EPA, who arranged for the testing.

The EPA Steps In

In response to these findings, the EPA released the results of their own Anvil 10+10 investigation just last week. They discovered eight different PFAS compounds in the fluorinated (a chemical coating) high-density polyethylene (HDPE) containers, with levels ranging from 20-50 parts per billion.

Despite these findings, the EPA has this to say concerning possible exposure:

“The PFAS detections...from the tested containers do not represent PFAS concentrations in the environment or human exposure to PFAS. While the EPA is early in its investigation, the agency will use all available regulatory and non-regulatory tools to determine the scope of this emerging issue and its potential impact on human health and the environment.”

PEER says this response, and the EPA’s general testing method, is not enough. Bennett says the EPA should be more proactive in warning the public about the possibility and implications of PFAS contamination in pesticides.

"We now have five different manufacturers that are selling PFAS-contaminated pesticides," Bennett said, noting PEER's latest findings. "This is a problem of epic proportions."

She’s also concerned that the EPA’s testing methods are too focused on PFAS coming from HDPE containers. PEER’s new tests (results listed above) revealed different PFAS compounds than were found in the Anvil 10+10 containers, raising questions about whether the chemicals could be getting into pesticides through other means.

Possible Contamination Causes

One theory Bennett proposed for explaining the contamination would be pesticide manufacturers listing PFAS chemicals as an “inert” ingredient, because there’s no requirement to disclose inert ingredients to consumers.

But there are pesticide manufacturers that dispute the claim. Megan Provost, president of Responsible Industry for a Sound Environment (RISE), which represents nonagricultural pesticide producers, said, “PFAS chemistry is not an active or inert ingredient in any pesticide formulation” made by members in her coalition. She instead blamed container manufacturers, saying “fluorinated packaging is used for some 20% to 30% of pesticide formulations to increase product and packaging integrity.”

What Now? States, Manufacturers Respond 

Regardless of who’s to blame, pesticides have a growing PFAS problem. In response, Anvil 10+10 manufacturer Clarke Mosquito Control Products Inc. confirmed in January that they voluntarily ceased all sales and shipments of the pesticide.

Massachusetts, Maine, and New York have all introduced or proposed bills that either limit or completely ban the use of any pesticide that contains (or might contain) PFAS due to florinated HDPE containers.

The EPA said they are “actively working with the Food and Drug Administration, the U.S. Department of Agriculture, and industry and trade organizations to raise awareness of this emerging issue and discuss expectations of product stewardship.”

If you suspect you have used a pesticide that may contain PFAS, you can file a report with the EPA here.

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EPA Extends Chlorpyrifos Public Comment Period; Future Use In Doubt

This month, the EPA extended the public comment period on its draft risk assessments (DRAs) and proposed interim decisions (PID) for chlorpyrifos to March 7, 2021. The purpose of the comment period is to “give the public and stakeholders more time to review and comment” on the December 2020 PID

This extended comment period is part of the effort the EPA needs to take following President Biden’s “Protecting Public Health and the Environment and Restoring Science to Tackle the Climate Crisis” Executive Order

The order aims to “review” actions taken by the previous administration across many government agencies. Action number 42 under the EPA section includes the “Chlorpyrifos; Final Order Denying Objections to March 2017 Petition Denial Order,” ruling. In “non-government speak,” this means the Biden administration is reviewing the sudden switch made by the Trump administration in early 2017 to block the outright ban of chlorpyrifos use - which started in 2015.

In a statement, the EPA said they will “follow the science and law in accordance with the Biden-Harris administration's executive orders and the Federal Insecticide, Fungicide, and Rodenticide Act in reviewing the chlorpyrifos DRAs and PID to ensure they are protective of public health and the environment.”

Back on the Ban Path?

Many news publications (both in and out of the agricultural science industry), see this “review” process as a sign that the Biden administration is considering a return to the 2015 chlorpyrifos ban proposal.

Successful Farming reports the way chlorpyrifos could ultimately be banned is still uncertain, but “some former EPA directors predict it will most likely be revoked via a voluntary cancellation.” This process can take as little as 30 days and only requires general agreement within the industry.

Chemical & Engineering News (c&en) says a voluntary cancellation would be “easier than five years ago” because unlike in 2015, Corteva Agriscience (formerly Dow AgroSciences), the largest maker of chlorpyrifos, is unlikely to fight a ban because they already agreed to phase out production last year.

The other option is a formal procedure to ban the pesticide that could take two to three years. In the past 40 years, there have been no formal cancellations of any pesticide, says Bill Jordan, a former deputy director at the Office of Pesticide Programs at the EPA and now an industry consultant and a volunteer at the Environmental Protection Network. “EPA has always thought voluntary cancellation was a faster, cheaper, better process than a formal cancellation,” he says. 

Regardless of the method used (if any at all), it’s clear to many that the EPA under the Biden administration will be very different compared to the Trump years. Biden himself has said he wants to take a close look at all current policies “that are harmful to public health, damaging to the environment, unsupported by the best available science, or otherwise not in the national interest.” 

Kari Hamerschlag, an advisor on the DNC Council on the Climate Crisis, said “Our goal in the Biden years is to root out the corporate dominance and interference in policy and try and get it back to policy that is actually healthy for people and the planet.”

Possible Consequences of a Ban

According to c&en, outright banning chlorpyrifos could create problems in the pesticide supply chain because on January 12, a federal court ruling directed the EPA to remove the pesticide sulfoxaflor, one of the few alternatives to chlorpyrifos for some applications, from the US market while the agency evaluates the risks of that chemical to endangered species. Environmentalists sued the EPA for allowing sulfoxaflor back on the US market in 2019, after the agency banned it in 2015 because of adverse effects on bees. 

The Current Course

The EPA is currently reevaluating 22 organophosphate pesticides, including chlorpyrifos, as part of a standard process to reassess pesticides after 15 years on the market. The agency expects to complete that review by Oct. 1, 2022. Unless the courts step in, or a voluntary cancellation occurs, chlorpyrifos use could continue until the end of the review.

To learn more about why there’s such an interest in banning chlorpyrifos, click here. If you would like to contribute to the conversation surrounding chlorpyrifos by submitting a public comment to the EPA, click here.

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EPA Extends Approval of Dicamba-Based Products for 2021 Season & Beyond

Just last week, the US Environmental Protection Agency (EPA) decided to approve new five-year registrations for two “over-the-top” (OTT) dicamba products—XtendiMax with VaporGrip Technology and Engenia Herbicide—and extended the registration for an additional OTT dicamba product, Tavium Plus VaporGrip Technology. The extended registrations are only for use on dicamba-tolerant (DT) cotton and soybeans and will expire in 2025. 

The decision is not free from controversy, however.


In a previous blog, we outlined the bumpy road dicamba has experienced over the past few years - culminating in June 2020 when the U.S. Ninth Circuit Court of Appeals blocked registrations for three major dicamba brands. The court’s decision was largely based on accounts of dicamba-based products drifting into nearby fields after application and destroying non-DT crops.

Despite the Circuit Court’s ruling, EPA Administrator Andrew Wheeler defended the decision."After reviewing substantial amounts of new information, conducting scientific assessments based on the best available science, and carefully considering input from stakeholders, we have reached a resolution that is good for our farmers and our environment,” Wheeler said.

Organizations like the American Farm Bureau, Georgia Cotton Commission, and weed scientists in the University of Georgia Extension praised the EPA’s decision mainly for “providing clarity” to farmers for the 2021 growing season and beyond. 

Dicamba critics see the decision differently, with The Center for Food Safety, Center for Biological Diversity, National Family Farm Coalition, and Pesticide Action Network North America planning to pursue a legal challenge.

What the Decision Means for Applicators

The EPA’s 2020 registration features important control measures to manage off-site movement of dicamba, including:

  • Requiring an approved pH-buffering agent (also called a Volatility Reduction Agent or VRA) be tank mixed with OTT dicamba products prior to all applications to control volatility.
  • Requiring a downwind buffer of 240 feet and 310 feet in areas where listed species are located.
  • Prohibiting OTT application of dicamba on soybeans after June 30 and cotton after July 30.
  • Simplifying the label and use directions so that growers can more easily determine when and how to properly apply dicamba.

The EPA claims these control measures provide new flexibilities for growers and also address the concerns expressed in regard to the June Court of Appeals ruling.

What are your thoughts on the new dicamba control measures? Let us know on social media!

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EPA Proposes Use of New Insecticide Active Ingredient

Earlier this week, the Environmental Protection Agency (EPA) proposed to register pesticide products containing a new active ingredient called tetraniliprole for sale and use in the US.

One of the “pesticide products” the EPA wants to register likely includes Bayer’s new and unnamed insecticide. According to Bayer, the tetraniliprole-based insecticide will be a 2-in-1 solution for both annual bluegrass weevil (ABW) and white grubs.

Bayer says that using tetraniliprole allows for season-long protection, immediate cessation of insect feeding following exposure, and consistent control of ABW and white grubs with just 1-2 applications per year. 

Although the use of tetraniliprole goes beyond just ABW and white grubs. According to the EPA, if approved, tetraniliprole will be the first registered diamide insecticide available in the US that controls corn rootworm larvae in corn through soil application, and flea beetles in corn and potatoes. It would also be the first diamide offering control of wireworms in potatoes and similar crops, and control of cutworms in tobacco via soil application.

Application Requirements

A study done by both the EPA and Canada’s Pest Management Regulatory Agency determined that tetraniliprole had no human health risk concerns. 

Still, the EPA is proposing specific mitigations to address potential ecological risks, including:

  • A 50-foot spray buffer for aerial application
  • A 25-foot spray buffer for ground applications
  • Directions for use for treated seed to reduce exposure to treated seeds for large birds
  • A 25-foot vegetative filter strip to reduce runoff into surface water

If you have any thoughts or concerns regarding tetraniliprole, let the EPA know! They’re accepting public comments on this proposal via docket EPA-HQ-OPP-2017-0233 at www.regulations.gov for 30 days, closing on Nov. 22, 2020.

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