US EPA announces proposal to add chitosan to the list of active ingredients permitted in exempted minimum risk pesticide products

Date:08-28-2020

By Lisa M. Campbell, James V. Aidala, Lisa R. Burchi, and Barbara A. Christianson

On August 20, 2020, the U.S. Environmental Protection Agency (EPA) announced that it is seeking to add chitosan to the list of active ingredients allowed for in minimum risk pesticides exempted from pesticide registration requirements under Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) Section 25(b).  A minimum risk product must meet six specific conditions to be exempted from pesticide registration.  One of those conditions is that the active ingredient in the minimum risk pesticide be one that is listed specifically by EPA.  If added to the list of minimum risk pesticide active ingredients, pesticide products containing chitosan could qualify as minimum risk pesticides provided the other conditions are also satisfied (e.g., using inert ingredients approved by EPA for use in minimum risk pesticides, not making any public health claims).

Chitosan is a naturally occurring polymer that is derived from the shells of crustaceans.  It is currently registered as a fungicide, antimicrobial agent, and plant growth regulator that boosts the ability of plants to defend against fungal infections.  For uses as a plant growth regulator, chitosan is applied to treat field crops, ornamentals, turf, home gardens, and nurseries.  Target pests include early and late blight, downy and powdery mildew, and gray mold.  As an antimicrobial agent, chitosan is used on textiles to protection the fabric from bacterial and fungal growth.  Chitosan is exempt from the requirement for a pesticide tolerance.

History -- The Caesar Salad Chemicals

The origin of the Section 25(b) list came from an effort by EPA to deregulate products which, while meeting the definition of being a pesticide (a product with the intended purpose of being sold or distributed to kill or repel a pest as defined under FIFRA), were common products of established safety.  More precisely, products with a lack of toxicity such that it was a “waste of resources” for EPA to subject such products to the bureaucratic requirements of FIFRA registration.

In particular, at an oversight Congressional hearing on the lack of progress being made at the time on EPA’s attempt to complete re-registration (now referred to as registration review), the EPA witness was asked about some most recently released re-registration assessments.  These referred to the four registered pesticides:  garlic, capsicum, acetic acid, and citric acid.  These are pesticides formulated into various products, and in the hearing were referred to by more common names: garlic, pepper, vinegar, and lemon juice.  This led to a famous oversight question to the EPA witness:  “Are you making progress or Caesar Salad?”

This led, in part, to the Office of Pesticide Programs (OPP) allowing very low risk pesticides to be exempt from registration.  It eventually issued the original Section 25(b) list to conserve review resources.  At the same time, since these products no longer had to be registered, it allowed label language such as “natural,” “non-toxic,” and “safe around children and pets,” which are disallowed registered product label claims.  Not surprisingly, label language allowing the word “safe” has proven to be a popular marketing claim for products that meet the exemption requirements.

At the same time, the fine print of the Section 25(b) exemption did not allow health and safety claims on such products even if they were made from Section 25(b) ingredients.  In particular, this led to concerns about insect repellents that could be made from Section 25(b) ingredients and were labeled as repelling mosquitoes or ticks or other public health pests; they could include the word “safe” as long they did not also mention any disease or other public health claims.  The average consumer, however, likely does not distinguish between insect repellents (or other products) that fit EPA’s definition of public health claims and those simply listing the target pest (e.g., mosquitoes, ticks, or rodents).  The average consumer is unlikely to realize the distinction between a product labeled as “XX insect repellent -- repels mosquitoes -- all natural and safe,” which may not have evidence of efficacy, and another product that says “YY insect repellent -- made from natural ingredients and repels mosquitoes, which may carry West Nile Virus” -- which is required to be registered and include proof of efficacy for any public health claims.

This possible consumer confusion was the subject of a FIFRA petition filed in 2006 by the Consumer Specialty Products Association (CSPA).  The petition suggests that EPA modify the Section 25(b) regulation to exclude products claiming to control public health pests from the Section 25(b) exemption -- which would then require registration, including data proving efficacy (Docket: EPA-HQ-OPP-2006-0687-0002).

EPA responded to the CSPA petition in 2007, essentially agreeing about the problem of possible consumer confusion.  In a letter to CSPA, EPA stated:

…. whether we decide to pursue rulemaking or some other avenue, we intend to move as expeditiously as possible to identify the most efficient approach to protect the public from unknowingly relying on products that target public health pests and have not been shown to work.

EPA later announced that it would embark on rulemaking to address this possible consumer confusion.  It is, however, unclear whether this is still a pending matter on EPA’s agenda.  No docket materials have been added in many years.  As part of its Semiannual Regulatory Agenda in fall 2011, EPA included an entry that stated a Section 25(b) proposed rule would be issued before February 2013.  It is not clear if EPA continues to have plans to issue such a proposal.

Commentary

EPA’s August 20 proposal is an interesting development, as EPA’s other revisions and proposals for minimum risk pesticides trend toward adding restrictions to the conditions to be satisfied, thus limiting exemptions.  The current proposal would expand the exemptions by adding another active ingredient to the otherwise limited approved list.  Since changes to the Section 25(b) list will require a rulemaking, it is unclear what happened to the earlier plan to issue a proposed rule addressing the long-ago CSPA petition response.

EPA states that it has forwarded to the Secretary of the United States Department of Agriculture (USDA) a draft regulatory document concerning “Pesticides; Addition of Chitosan to the List of Active Ingredients Allowed in Exempted Minimum Risk Pesticides Products.”  EPA will not make this draft regulatory document available to the public until after it has been signed.  When it is available, that document and additional information will be available in docket EPA-HQ-OPP-2019-0701.

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