Editors' Summary: This Article is the second in a two-part series that examines the promise and reality of Clean Air Act enforcement by reviewing four central enforcement issues: (1) the development of the "any credible evidence" rule; (2) the evolution of the compliance assurance monitoring proposal; (3) the controversy over the requirement of federal enforceability of limitations on a source's potential to emit pollutants for purposes of determining its status as a "major source" under the Act; and (4) the tension between state-law voluntary disclosure, immunity, andenvironmental audit privileges and EPA's enforcement policy for state Title V operating permit programs.

This Article briefly reviews some of the new enforcement tools created by Congress through the 1990 Clean Air Act Amendments. It then discusses the requirement of federal enforceability with respect to determination of a source's potential to emit under the Act. Next the Article reviews the controversy over the environmental-audit privilege and voluntary-disclosure policy that has erupted largely in response to the prospect of heightened enforcement of the Act. It concludes that although EPA probably has the legal authority to achieve its enforcement objectives, the Agency must adopt a pragmatic approach to maintain the partnership with the states that is critical to successful clean-air enforcement.