Federal law divides the responsibility of enforcing federal environmental regulations between federal agencies, typically the U.S. Environmental Protection Agency (EPA), and state agencies.¹ Generally, state programs receive formal approval or authorization from EPA to administer the federal environmental program.² EPA usually combines the delegation of authority to the states with retained enforcement authority for themselves.³

It is this federally retained enforcement authority that causes conflict between the states and EPA, presenting many legal questions when EPA chooses to initiate its own enforcement action.⁴ This practice of EPA taking enforcement action in a state that is authorized to administer a federal program is known as "overfiling."⁵ Overfiling by EPA is intended to promote consistent enforcement of federal regulations and protect against inadequate state enforcement actions.⁶

This Article compares two conflicting cases of EPA overfiling, United States v. Power Engineering Co.⁷ and Harmon Industries, Inc. v. Browner⁸ to determine whether (1) the statutory language of the Resource Conservation and Recovery Act (RCRA) and (2) the doctrine of res judicata bar overfiling by EPA.

The Article will first give general background on RCRA.⁹ Second, the Article discusses overfiling in the context of RCRA.¹⁰ It should be noted that this Article is limited to overfiling that occurs in the enforcement of RCRA.¹¹ Third, the Article compares the Harmon and Power Engineering statutory analysis of RCRA.¹² The Article then compares the Harmon and Power Engineering analysis of res judicata.¹³ Lastly, the Article concludes that the language of RCRA and the doctrine of res judicata prevent overfiling only if the state has taken action and federal issues enforced are the same or substantially similar to EPA's interests.¹⁴