While Congress writes laws that determine national priorities for handling environmental problems, federal agencies write environmental regulations that bridge the gap between Congressional intent and actual implementation of statutes. In developing and codifying regulations, federal bureaucrats make policy decisions and negotiate to resolve conflicts within and outside their agencies. These conflicts usually remain hidden from the public and are not documented. Nevertheless, the content of regulations may be influenced by human and political factors as much as by competent scientific and technical research and policy judgements. Therefore, regulation writers must remain flexible to respond to events as they arise, especially ones that result in deviations from institutionalized systems for regulatory development. The process of developing a single regulation was traced to give insight into the regulatory development process at the U.S. Environmental Protection Agency. Observations, perceptions, and experiences of a participant in the process were documented to show the informal workings of the Agency that outsiders rarely see. Two lessons drawn from this exercise are that the regulatory development process does not follow a "cookbook" formula and having a strategy to advance a regulation can help to ensure its successful development.