Editors' Summary: EPA's RCRA enforcement program will face a serious threat as defendants begin to raise statute of limitations defenses. The five-year federal statute of limitations is now expiring for many RCRA violations. Many statute of limitations issues remain unresolved, including what, if any, is the proper statute of limitations in civil or criminal court actions and when does it begin running, and whether administrative proceedings toll the statute. The author explores the application of the federal five-year statute of limitations in states with and without EPA-approved RCRA programs and discusses EPA's options for responding to the statute of limitations defense. She concludes that EPA may be able to assert the discovery rule or characterize violations as ongoing, but suggests that EPA consider regulatory changes to fully protect its causes of action. Further, Congress should clarify the issue during the reauthorization of RCRA, as it did in the 1986 CERCLA amendments.