Page:Michigan v. EPA.pdf/25

 Cite as: 576 U. S. ____ (2015)

3

KAGAN, J., dissenting

initial “appropriate and necessary” finding, EPA knew it would do exactly that—knew it would thoroughly consider the cost-effectiveness of emissions standards later on. That context matters. The Agency acted well within its authority in declining to consider costs at the opening bell of the regulatory process given that it would do so in every round thereafter—and given that the emissions limits finally issued would depend crucially on those accountings. Indeed, EPA could not have measured costs at the process’s initial stage with any accuracy. And the regulatory path EPA chose parallels the one it has trod in setting emissions limits, at Congress’s explicit direction, for every other source of hazardous air pollutants over two decades. The majority’s decision that EPA cannot take the same approach here—its micromanagement of EPA’s rulemaking, based on little more than the word “appropriate”—runs counter to Congress’s allocation of authority between the Agency and the courts. Because EPA reasonably found that it was “appropriate” to decline to analyze costs at a single stage of a regulatory proceeding otherwise imbued with cost concerns, I respectfully dissent. I

A

The Clean Air Act Amendments of 1990, as the majority describes, obligate EPA to regulate emissions of mercury and other hazardous air pollutants from stationary sources discharging those substances in large quantities. See ante, at 2. For most industries, the statute prescribes the same multi-step regulatory process. At the initial stage, EPA must decide whether to regulate a source, based solely on the quantity of pollutants it emits and their health and environmental effects. See 42 U. S. C. §§7412(a)(1), (a)(2), (c)(1), (c)(3); ante, at 2. Costs enter the equation after that, affecting the emissions limits that the eventual regulation will require. Under the statute, EPA