International Paper Co. v. Ouellette, 479 U.S. 481 (1987) (U.S. Supreme Court)
International Paper Co. v.
Does the Clean Water Act preempt a downstream (affected) state from applying its own common law (e.g., nuisance) to an out-of-state point source, or may plaintiffs pursue only the source state's law for interstate water pollution claims?
The Clean Water Act's comprehensive permitting scheme preempts the application of an affected state's common law to an out-of-state point source. However, the Act does not preempt state common-law claims brought under the law of the source state. The Act's savings provisions preserve the source state's ability to impose and enforce more stringent requirements on its own dischargers, including through common-law remedies, but do not authorize extraterritorial application of another state's tort law that would conflict with or undermine the NPDES program.
The CWA preempts application of Vermont common law to International Paper's New York discharge. Plaintiffs may not proceed under Vermont law but may pursue claims under New York (the source state's) law. The judgment was reversed and remanded to allow plaintiffs to amend their complaint to assert source-state claims.
Ouellette is the leading case on the CWA's preemptive effect over interstate state-law tort claims. It delineates a bright-line choice-of-law rule: only the source state's law may govern tort suits against out-of-state point sources. This preserves state common-law remedies without allowing downstream states to impose extraterritorial standards that would destabilize the NPDES program. For law students, the case is essential for understanding environmental federalism, the scope of statutory preemption, how savings clauses operate, and the strategic implications for forum selection and choice of law in pollution litigation.