Monsanto v. Durnell · ¶122

This, in turn, must mean that the EPA’s (not infallible) approval of a pesticide’s label does not establish a “rule of law that must be obeyed” when it comes to the pesticide’s label. Id., at 445. Because the EPA’s registration decision is not conclusive of the label’s compliance with the statute, that registration decision itself cannot carry the force of law, much less capture the universe of requirements with which a manufacturer must comply to prevent its product from being misbranded in violation of FIFRA. To conclude otherwise would turn the registration decision from “prima facie evidence” of compliance with FIFRA into conclusive proof of such compliance. It defies logic to treat the EPA’s approval of a pesticide’s label as creating a legal requirement under FIFRA when that approved label may not comply with the law.

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