## Facts

- Dow AgroSciences sought EPA registration for insecticides containing sulfoxaflor, a systemic insecticide in the sulfoximine class.
- EPA recognized sulfoxaflor as highly toxic to honey bees and evaluated pollinator risk using a tiered framework moving from lab studies to semi-field and field studies when earlier tiers indicate concern.
- In early 2013, EPA proposed a conditional registration with lower rates and mitigation measures, anticipating additional data.
- In May 2013, without obtaining reliable higher-tier field studies, EPA instead issued an unconditional registration for multiple sulfoxaflor products.
- EPA’s registration record acknowledged limited and flawed field studies and continuing data gaps regarding pollinator risks under field-realistic conditions.
- Beekeeping and pollinator-protection groups petitioned for review in the Ninth Circuit under FIFRA, challenging the registration decision.

## Issues

1. Whether EPA’s unconditional registration of sulfoxaflor was supported by substantial evidence under FIFRA and was not arbitrary and capricious given acknowledged data gaps and uncertainty about pollinator risk.
2. Whether EPA failed to follow, or adequately explain departure from, its tiered pollinator risk-assessment framework and related data expectations when registering sulfoxaflor.

## Decision

- The Ninth Circuit granted the petition for review.
- The court vacated EPA’s sulfoxaflor registration and remanded to EPA for further proceedings.
- The court held the unconditional registration was not supported by substantial evidence because EPA lacked reliable field data and had admitted important aspects of pollinator risk were unknown.
- The court emphasized that EPA could not deem field studies inadequate yet rely on them as support for an unconditional registration.
- The court treated mitigation measures and conservative modeling assumptions as insufficient substitutes for the missing reliable higher-tier data.

## Legal Principles

- Under FIFRA, EPA registration decisions must be supported by substantial evidence on the record as a whole; evidence must be adequate for a reasonable decisionmaker to support the agency’s conclusion.
- An agency may not convert acknowledged data gaps or unreliable studies into affirmative evidence that a pesticide will not cause unreasonable adverse effects on the environment.
- When an agency adopts a methodological framework (including data expectations triggered by identified risk), it must follow it or provide a reasoned explanation for departure.
- Where a pesticide is highly toxic to a non-target organism and real-world exposure and effects remain uncertain due to unreliable field evidence, an unconditional registration may fail FIFRA’s evidentiary requirement.

## Conclusion

The Ninth Circuit vacated EPA’s unconditional registration of sulfoxaflor because the agency proceeded despite unreliable field studies and unresolved data gaps about pollinator risk, leaving the record without substantial evidence that the pesticide would avoid unreasonable adverse environmental effects.


Pollinator Stewardship Council v. EPA, 806 F.3d 520 (9th Cir. 2015)