Environmental Defense v. Duke Energy Corporation
Headline: Vacates lower court’s rewrite of EPA’s PSD rules, ruling the court improperly invalidated the agency’s 1980 permitting regulations and remanding power-plant upgrade disputes for further review.
Holding: The Court held that the Fourth Circuit improperly construed EPA’s 1980 PSD regulations to mirror NSPS hourly-emissions rules, effectively invalidating those PSD regulations, vacated that judgment, and remanded for further proceedings.
- Stops lower courts from rewriting EPA PSD rules during enforcement
- Keeps disputes about specific permits open for further factual review
- Allows challenges to agency inconsistency to be raised on remand
Summary
Background
A power company replaced or redesigned dozens of tube assemblies in coal-fired generating units to extend their operating life and run longer. The federal government and environmental groups sued, saying those projects required Prevention of Significant Deterioration (PSD) permits under EPA rules. The company argued the projects did not increase hourly emissions rates, so no PSD permit was needed. Lower courts sided with the company by reading PSD rules to require an hourly-emissions test.
Reasoning
The Court examined how Congress and EPA defined “modification” in two related pollution programs. EPA’s NSPS rules looked to increases in an hourly emissions rate, while its 1980 PSD rules measured actual annual emissions averaged over two prior years in tons per year. The Court held the Fourth Circuit went too far by rewriting the 1980 PSD regulations to match the NSPS hourly test, effectively invalidating the PSD rules as written. The Court vacated the appeals judgment and sent the case back for further proceedings.
Real world impact
The decision prevents courts from quietly rewriting EPA’s PSD regulations in enforcement cases and preserves the statutory limits on when a regulation’s validity can be attacked. The ruling leaves open further factual and legal challenges about whether particular projects trigger PSD permitting and allows the power company to press claims about inconsistent or retroactive agency positions on remand.
Dissents or concurrances
One Justice agreed with the outcome but disagreed with part of the Court’s discussion about whether the PSD cross-reference required identical regulatory meaning, offering a narrower view that the cross-reference supports a single definition.
Opinions in this case:
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