## Facts

- Ciba-Geigy Corporation registered the pesticide diazinon under the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA).
- The Environmental Protection Agency (EPA) identified concerns about bird mortality linked to diazinon applications on golf courses and sod farms.
- Under FIFRA § 6(b), EPA issued a notice of intent to cancel diazinon registrations for those uses on the ground that they “generally cause unreasonable adverse effects on the environment.”
- After hearings, EPA’s Chief Administrative Law Judge recommended restricted-use classification and labeling changes, but not cancellation for golf-course and sod-farm uses.
- EPA staff appealed, and the EPA Administrator rejected the ALJ’s recommendation and ordered cancellation (a ban) for diazinon use on golf courses and sod farms, relying primarily on risks to birds.
- Ciba-Geigy petitioned for review, arguing the Administrator misapplied the statutory word “generally” in FIFRA § 6(b).

## Issues

1. Whether FIFRA § 6(b) requires EPA to find that diazinon causes bird deaths “more often than not” to conclude it “generally causes unreasonable adverse effects on the environment.”
2. Whether the EPA Administrator applied an incorrect legal standard by treating any unreasonable risk in some applications as sufficient to satisfy the statutory requirement that the pesticide “generally” causes unreasonable adverse effects.

## Decision

- The court held that FIFRA does not require a showing that diazinon kills birds in a majority of applications to support cancellation; the statute permits regulation based on unreasonable risk.
- The court held that the Administrator’s analysis gave no meaningful effect to the word “generally” and therefore applied an incorrect legal standard.
- The court granted the petition in part and remanded to EPA for reconsideration under the correct interpretation of “generally.”
- The court did not decide whether cancellation was ultimately warranted and did not reweigh the evidence on the merits.

## Legal Principles

- Under FIFRA, “unreasonable adverse effects on the environment” includes “any unreasonable risk,” determined by considering economic, social, and environmental costs and benefits.
- When Congress uses qualifying language (such as “generally”), an agency must give it independent operative meaning and may not treat it as surplusage.
- In FIFRA § 6(b), “generally causes” imposes a frequency/pervasiveness component: EPA must address how often the unreasonable risk arises for the uses at issue, not merely whether such a risk can arise.
- “Generally” does not necessarily mean “more than half,” but it requires more than identifying isolated or occasional instances; the agency must articulate and apply a standard tied to appreciable frequency and the statutory cost–benefit balancing.
- Reviewing courts may remand when an agency applies an incorrect statutory standard, even if the agency has discretion over the ultimate policy judgment within that standard.

## Conclusion

The Fifth Circuit required EPA to interpret and apply FIFRA § 6(b) in a way that gives substantive effect to “generally,” remanding the cancellation decision because the Administrator treated the existence of unreasonable risk in some applications as sufficient without analyzing whether such risk occurs with adequate frequency to meet the statute’s threshold.


Ciba-Geigy Corp. v. U.S. Env’t Prot. Agency, 874 F.2d 277 (5th Cir. 1989)