Registration Review of Pyrethrins and Pyrethroids

In 2019 and 2020, EPA published the following documents:

• A white paper reevaluating the FQPA safety factor for pyrethroids. Learn more about how the FQPA safety factor is applied in the review of pyrethroids.
• A second white paper explaining the insufficiency of the current physiologically based pharmacokinetic (PBPK) model to estimate uncertainty factors for individual pyrethroid risk assessments.
• The Agency’s Ecological Risk Mitigation Proposal for 23 pyrethroids/pyrethrins.
• The Agency’s Revised Ecological Risk Mitigation for 23 pyrethroids/pyrethrins.

Ecological Risk Assessments and Mitigation

In late 2016, EPA released a draft ecological risk assessment for eight pyrethroids plus the pyrethrins and a risk management rationale for the remaining pyrethroids currently undergoing registration review.

The Agency assessed the pyrethroids and pyrethrins as a class rather than by individual chemical for the draft ecological risk assessment to increase efficiency and consistency in the risks assessed and to implement consistent risk mitigation.

To address potential risks of concern for terrestrial/aquatic invertebrates and fish described in the 2016 draft ecological risk assessments, EPA has determined that ecological risk mitigation to reduce spray drift, reduce runoff, and promote soil conservation practices for the entire class of pyrethrins and pyrethroids is necessary. Read the Ecological Risk Mitigation Proposal and the Revised Ecological Risk Mitigation for more detail.

List of Pyrethrins and Pyrethroids

*Etofenprox is not a pyrethroid or pyrethrin but was assessed with the group due to its structural similarity.