For decades, policymakers in the United States have required firms either to install specific pollution-control technologies or to ensure that emissions from their smoke stacks or drain pipes stay within specific limits. This twopronged approach of environmental technology requirements and emissions limits has succeeded in reducing certain types of environmental problems. Yet this approach, which forms the backbone of the nation’s environmental protection system, has for the most part ignored what goes on inside the firms and facilities that actually generate pollution. As long as companies deployed the appropriate technologies or met the specified emissions targets, how they managed their facilities and what systems they used to monitor their environmental performance mattered to no one other than the company managers themselves, and perhaps their corporate boards and shareholders. Policymakers and others interested in environmental protection treated the firm itself as a black box (Salzman and Thompson 2003, 182).