As Easy as 1, 2, 3? EPA’s New Herbicide Strategy to Protect Endangered Species Under FIFRA Gets Mathematical

EPA primarily regulates the sale, distribution and use of pesticides pursuant to its authority under the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA). Under FIFRA, EPA is involved with the registration of new pesticides (i.e., pesticides with new active ingredients or new uses) as well as the periodic re-evaluation of existing pesticides. Moreover, EPA has enforcement authority over users of registered pesticides, such as when an herbicide—which is regulated and registered under FIFRA—is used in a manner inconsistent with its labeling.

When EPA conducts registration actions, it is required under the Endangered Species Act (ESA) to ensure that its actions are not likely to jeopardize the continued existence of threatened or endangered (“listed”) species, or result in the adverse modification of their critical habitats. Under this obligation, EPA is also required to consult with agencies such as the Fish and Wildlife Service (FWS).

According to EPA, in the past decades EPA has “struggled” to meet this obligation under the ESA for the “thousands” of actions it completes annually under FIFRA—noting that the consultation process with FWS can take “years for a single pesticide” to be completed. As it currently stands, there are over 1,700 listed species EPA must assess in order to meet its ESA responsibilities while evaluating pesticides under FIFRA. To that end, EPA has been weighing more efficient approaches to integrating the consideration of endangered and threatened species into its activities under FIFRA, to keep pace with its ESA obligations, and generate efficiencies at the front-end of the pesticide registration process.

As a result, on August 20, 2024, EPA announced its new Herbicide Strategy, which is intended to create a “consistent, reasonable, transparent, and understandable” approach for assessing potential impacts and identifying mitigations for listed species affected by the use of agricultural herbicides. EPA believes its Herbicide Strategy promotes two dual goals: the protection of endangered species and their habitats from herbicides earlier in the regulatory process, while also creating greater regulatory certainty and reducing litigation risk (i.e., the legal vulnerability of EPA’s pesticide decisions), which is both beneficial to producers and users of these products. EPA also believes that implementing this Herbicide Strategy into the front end of its FIFRA evaluations will increase the efficiency of consultations with FWS on the back end as well. For instance, EPA believes that when mitigation is implemented early, impacts to species can thereby be reduced, leaving only a limited number of remaining impacts to focus upon during consultation with FWS. In turn, labels could then be altered if additional mitigation is later determined to be required based on any remaining impacts.

The Herbicide Strategy’s Framework

EPA’s new Herbicide Strategy involves a three-step framework for EPA to use when evaluating new or existing herbicides under FIFRA. Notably, this framework only applies to herbicides used in the contiguous United States for agricultural purposes—including orchards, vineyards, Christmas trees, row crops, specialty crops, and flooded crops. It is important to note that EPA’s Herbicide Strategy was issued as non-rulemaking and is considered by the agency to be “self-implementing.” To that end, EPA will likely use this framework when registering or re-registering herbicides and determining their labeling requirements. Thus, enforcement of this policy will likely be carried out when an herbicide user does not follow the new instructions set forth on the label—described in more detail below.

Step One:

At step one, EPA will evaluate the potential for population-level impacts to the listed species, based on long standing FIFRA risk assessment approaches. The key takeaway from this step is that EPA intends to run models and analyze various factors and data points in order to compare exposure and toxicity estimates—to then ultimately determine whether grouped listed species face a not likely, low, medium, or high potential for population-level impacts from the herbicide.

Step Two:

At step two, EPA will essentially assign levels of mitigation based on the population-level impacts determined in step one. The mitigation levels are essentially intended to reduce exposure pathways such that population-level impacts are reduced to “not likely” when the herbicide is used. Generally speaking, these levels of mitigation correlate with population-level impacts: low population impacts = low mitigation required, high population impacts = high mitigation required, etc. EPA notes, however, that in determining the mitigation level, it may take into account any existing or proposed mitigations that the registrant already intends to include on the product label or commits to writing.

The mitigation levels apply under two circumstances (1) spray drift, and (2) runoff and erosion.

Spray Drift

For spray drift, EPA requires a buffer distance for each mitigation level. Thus, for aerial, ground, and air blast sprays of herbicides, the distance associated with that buffer increases with the level of mitigation (low, medium, and high) required. For example:

_{* Medium impact is excluded from this table as EPA intends to use modeling to determine the requisite buffer and has therefore not set numerical values for buffer distance.}

EPA’s Herbicide Policy, nevertheless, identifies various mitigation measures a user can rely on, such as using a windbreak or hedgerow on the downside of application, that can then be “credited” or applied to the required buffer distance. Consequently, if the user of the herbicide combines various mitigation methods, they may mathematically reduce the buffer distance required by the mitigation level all the way down to zero.

To illustrate, let’s assume an herbicide requires a high mitigation level (due to a high potential population-level impact), and the site it is being used at is using the herbicide as an aerial spray. The required buffer for spray drift would start out at 320 feet. Now assume this site has a basic windbreak or hedgerow, the spray has a very coarse droplet size distribution, and the relative humidity is 60% or more at time of application. EPA has determined that those mitigation measures reduce the buffer required by 50%, 40% and 10%, respectively. Consequently, the new buffer required would be 0 feet, so long as all three mitigation measures are used or are in existence at the time of application.

In practice, an applicator would select mitigation measures to determine how much the buffer distance on the pesticide product label can be reduced prior to application. In addition to these mitigation measures, EPA also will permit downwind managed areas to count toward the reduced buffer distance. For more information on potential mitigation measures for spray drift and their corresponding percentage reductions, see Tables 7-9 of the Herbicide Strategy. For more information on downwind managed areas see Table 10 and section 3.2.1.4 of the Herbicide Strategy.

Runoff and Erosion

EPA intends to use a similar “mathematical” approach to address the mitigation levels assigned for runoff and erosion concerns. Where EPA identifies that population-level impacts of an herbicide are associated with runoff or erosion, EPA will likewise assign a corresponding mitigation level, and each mitigation level corresponds with a number of “points,” as illustrated below.

Similar to spray drift, EPA has developed a wide variety of mitigation measures with varying point values that can be used to achieve the required mitigation points. These mitigation measures are generally categorized as: application parameters, field characteristics, in-field mitigation measures, adjacent to the field mitigation measures, systems that capture runoff and discharge, and other measures. Mitigation measures generally range from 1 to 4 points, and those measures deemed to have a higher efficacy for preventing runoff and erosion provide more points toward mitigation.

Essentially, a user is required to implement mitigation measures to reduce the starting point value of the herbicide down to zero prior to application. For example, assume an herbicide user needs to achieve 6 mitigation points. The user could combine the following mitigation measures (with varying levels of efficacy) to achieve a total of 6 mitigation points: soil incorporation (watering-in before runoff producing rain event) (low efficacy - 1 point); reservoir tillage (reservoir tillage, furrow tillage or basin tillage) (high efficacy – 3 points), and the field has a slope of ≤ 3% (naturally low slope or flat) (medium efficacy - 2 points). Added together, these 6 mitigation points reduce the starting balance of points (6) down to zero.

As EPA plans to implement this program at the FIFRA stage, users will likely see the number of mitigation points required on the label of the herbicide. Users will then be directed from the label to view a “mitigation menu” online, in order to decide for themselves how they intend to achieve the required mitigation points. EPA believes this approach will provide greater flexibility to applicators or growers as users can choose which measures, field characteristics, or parameters make sense for their circumstances; moreover, EPA can continuously add to the menu of options or revise mitigation measures as their efficacy evolves—which will ultimately improve and expand upon the menu of options.

In addition to the menu of mitigation measures, EPA also intends to credit points for growers or applicators that work with a runoff or erosion technical expert or those who participate in a conservation program meeting certain minimum specifications. For more information on how these points will be credited, see sections 3.2.2.6.1 and 3.2.2.6.2 of the Herbicide Strategy.

Step Three:

At the final step of the Herbicide Strategy, EPA will identify where in the U.S. the mitigation levels identified in step two will apply. In some cases, EPA expects the mitigation levels to apply across the “full spatial extent of a use pattern (e.g., specific crops),” whereas other mitigation levels may only be necessary in geographically-specific areas—referred to as a pesticide use limitation areas or PULAs. Users of the herbicides would be responsible for reviewing these specific areas on an EPA website to determine whether they are required to comply with any geographically specific mitigation levels.

Conclusion:

Under the ESA, EPA is required to consider impacts to listed species when undertaking evaluations of new or existing herbicides under FIFRA. EPA has developed a new Herbicide Strategy, which includes a three-step framework, in an effort to confidently identify potential impacts to endangered species and assign flexible mitigation measures for spray drift, runoff, and erosion. Those mitigation measures can then be implemented in a variety of ways depending on a user’s crops, existing field conditions, or geographic area. EPA believes this integrated approach will be beneficial to both endangered species as well as the regulated community, such as herbicide producers and their users.

EPA’s intended approach, which includes identifying mitigation measures and then calculating reduced buffer distances or adding up mitigation points, may create a lot of new and confusing burdens for users of herbicides—which are important to consider in light of EPA’s civil and criminal enforcement authority under FIFRA for pesticide misuse and/or noncompliance with a requirement set forth in a label. EPA recognizes that this mathematical approach to mitigation may be “complicated,”—that it is not as easy as 1, 2, 3—so it’s important for applicators, growers, and agricultural stakeholders alike to be aware of this new strategy and “check their work” as new herbicides come to market or existing herbicides are re-evaluated under FIFRA.

The Herbicide Strategy is available to download here.