Enforcement was much on the mind of Congress when it drafted the Clean Air Act Amendments of 1970.¹ The Act gave the Environmental Protection Agency (EPA) broad authority to monitor the emissions of individual polluting facilities and to seek the imposition of potentially severe sanctions on violators. In the first six years of the Act's existence, however, EPA's attention focused less on enforcement than on developing and defending a regulatory and institutional framework for implementing the Act. By the mid to late 1970s, the majority of stationary sources had come into compliance. Nevertheless, more than a thousand major emitters remained in violation. Among those that had attained compliance, the often difficult and expensive task of maintaining compliance was frequently neglected in the absence of oversight and prodding by enforcement agencies. Consequently, EPA has devoted an increasing proportion of its operating budget to enforcement-related activities.

In 1977, armed with enhanced enforcement authority,² EPA increased its enforcement and monitoring activities significantly. This surge in activity led inevitably to a number of legal challenges to the scope of the Agency's enforcement powers.³ Of these, the most frequently litigated has concerned the use of non-EPA employees in conducting field monitoring and source inspections.