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May 13, 2013

EPA Publishes Final Data Requirements for Antimicrobial Pesticides

The ACTA Group

On May 8, 2013, the U.S. Environmental Protection Agency (EPA) issued a long-awaited final rule revising the data requirements for antimicrobial pesticide products. EPA states the revisions “reflect current scientific and regulatory practice, and [] provide the regulated community with clearer and transparent information about the data needed to support pesticide registration decisions for antimicrobial products.” The final rule revises and updates the data requirements for antimicrobial pesticides that are currently found in 40 C.F.R. Part 161, and relocates them to Subpart W of Part 158. Subpart W sets out data requirements specific to antimicrobial products that are described by the antimicrobial use patterns and use exposure considerations particular to antimicrobials. The final rule is effective July 8, 2013.


The data requirements that currently apply to antimicrobial pesticide products are codified in 40 C.F.R. Part 161. First promulgated in their current form in 1984, these requirements were developed primarily for agricultural pesticides and do not address antimicrobial use patterns specifically. EPA proposed data requirements for antimicrobial pesticides in 1999 that were subject to substantial comment and never issued in final. EPA revised the data requirements in 40 C.F.R. Part 158 applicable to conventional and biological pesticides in October 2007. The existing data requirements, with continuing applicability only to antimicrobials, were moved to Part 161. On October 8, 2008, EPA proposed rules that would eliminate the current Part 161 and promulgate the revised requirements for antimicrobials in Part 158, Subpart W. That proposed rulemaking was subject to considerable public comment. This final rule promulgates the rule as proposed, with certain changes.


With this final rule, EPA for the first time has issued final data requirements specific to antimicrobial products. Consistent with the proposed rule, EPA states that for the final rule it is using the term “antimicrobials” to refer collectively to antimicrobial pesticides, antifoulant coatings and paints, and wood preservatives. The new data requirements apply to all of these product classes.

Also consistent with the proposed rule, EPA has structured the data requirements by organizing antimicrobial products into 12 use categories: agricultural premises and equipment; food-handling/storage establishments, premises and equipment; commercial, institutional and industrial premises and equipment; residential and public access premises; medical premises and equipment; human drinking water systems; materials preservatives; industrial processes and water systems; antifoulant paints and coatings; wood preservatives; swimming pools; and aquatic areas. Data requirement applicability depends in part on the appropriate use categories. EPA also has developed a use site index that EPA describes as comprehensive and that is intended to link specific antimicrobial product uses with one of these 12 use categories. EPA does not appear to have yet updated its current conventional use site index, available on EPA’s website, to include antimicrobial products, but presumably this will occur well before the July 8, 2013, effective date.

EPA has stated that, with the new data requirements, it has sought to update the applicable data requirements to reflect changes in each of the applicable science disciplines over time and incorporate data requirements that are not currently codified in the regulations but that EPA states it regularly requires as part of “current practices” under 40 C.F.R. Section 158.75. Data requirement applicability is indicated on a use category basis, as stated above, but also on a food (including direct and indirect) and nonfood use basis. EPA has eliminated the “high” and “low” exposure designations in the proposed rule and instead defined the data requirements along these use category lines.

As for conventional and biological pesticides, for each of the science disciplines, EPA has listed the data requirements, correlated them with the use categories, specified the required test substance, and indicated whether the data requirement is required, conditionally required, or not required. The science disciplines addressed in the new Part 158 Subpart W are: product chemistry; product performance; toxicology; nontarget organisms; nontarget plant protection; applicator exposure; post-application exposure; environmental fate; and residue chemistry. For several of the science disciplines, EPA has adopted a tiered approach to data development. Additional testing may be required subsequently based on the test results of initially required studies. For each discipline and set of data requirements, EPA has provided extensive notes that elaborate on the conditions under which data are required or considerations pertinent to waiver requests.

The final rule expands the number of newly required studies from eight to 11, including developmental neurotoxicity, immunotoxicity, and several environmental fate studies. The three additional new studies are photodegradation in soil for wood preservative uses, and two simulation studies to assess chemical biodegradability in discharged waste water and activated sludge units. EPA made several additional changes between the proposed and final rule, including changing some studies from not required to conditionally required, or from conditionally required to required; changing the number of test species; and/or expanding the number of use patterns for which a test is required. EPA also revises key definitions, including those for sanitizer and disinfectant. EPA states that it has received many comments on these definitions in the context of the proposed rule as well as the draft Series 810.2000 study guidelines, and that “EPA believes that the definitions being codified in part 158, subpart W reflect the input received from the regulated community in multiple submissions.”

Finally, EPA states: “While current practice is still largely dependent on animal (in vivo) testing, this rule is one milestone towards the Agency’s longer term vision for 21st Century Toxicology and new integrated testing strategies. OPP believes that certain classes of chemicals, such as antimicrobial pesticides, provide an appropriate starting point for OPP’s planned transformation. . . The ready availability of published literature and publicly-available assessments offer a unique opportunity for the applicant to use the available information as a starting point for fulfilling data requirements, and, when appropriate, to use computer modeling and/or in vitro data to supplement or fulfill data requirements.” EPA provides one example of this transformation — its voluntary pilot program for eye irritation testing using an in vitro method — but discusses several ongoing efforts.


Considering the current regulations applicable to antimicrobial pesticides date back to 1984 and were focused primarily on agricultural uses, most stakeholders agree that revisions to the data requirements were badly needed. To the extent that the regulations now provide greater clarity and transparency about the data requirements for these pesticides, the regulations will assist industry in determining what data EPA requires for particular antimicrobial pesticides with particular use patterns. The regulations also, however, will increase the data requirements for many products that, in turn, will result in increased costs to conduct studies, increased time to complete the registration process, and greater uncertainty as to the eventual outcome given the new variables that must be considered. EPA states that under the final rule:

  • The average cost per registration action of a new antimicrobial active ingredient is approximately $1 million to $5 million.
  • In the context of registration review, the average additional data costs are expected to be approximately:
    • $588,000 for wood preservatives;
    • $284,000 for food and indirect food uses; and
    • $260,000 for all other uses.

The new Part 158 Subpart W is instructive to registrants seeking new registrations or amendments and to existing registrants as their active ingredients enter the registration review cycle. Registrants with active ingredients entering registration review will want to evaluate these data requirements closely and plan accordingly.

Additionally, even with EPA’s pesticide use site index, sorting out data requirements may still confuse those attempting to determine how best to satisfy data requirements, making consultation with EPA an important and perhaps essential step in the registration process. This is especially true given EPA’s implementation of the Pesticide Registration Improvement Renewal Act (PRIA 3) technical screening process and its exceedingly short ten-day window for correcting deficiencies.