Editors' Summary: The U.S. Supreme Court's 1984 landmark decision in Chevron U.S.A., Inc. v. Natural Resources Defense Council (Chevron) set out a two-step test for determining when to accord deference to federal agency interpretations of statutory provisions, holding that where a statute is ambiguous, the judiciary must defer to any reasonable interpretation offered by the agency charged with administering the statute. This Article examines City of Chicago v. Environmental Defense Fund and PUD No. 1 of Jefferson County v. Washington Department of Ecology, two 1994 cases in which the Supreme Court had to decide whether the U.S. Environmental Protection Agency's interpretations of environmental statutes were entitled to deference under Chevron. The authors point out that in both cases, the Supreme Court's application of the Chevron test focused primarily on whether the statute at issue was ambiguous, thus avoiding the second part of the Chevron inquiry. They discuss the "plain-meaning" approach to determining whether a statute is ambiguous, and the problems that approach faces with respect to increasingly detailed and complex environmental statutes. The authors conclude that the plain-meaning approach to statutory interpretation may have the effect of putting the courts, rather than the federal agencies, in the position of shaping environmental policy, ultimately changing Chevron from a doctrine of deference into a doctrine of antideference.