“Institutionalized science ethics” refers to the statutory, professional and institution-based ethical standards that guide and constrain scientists' research work. The primary institution responsible for implementing institutionalized science ethics is the Institutional Review Board. We examine the limitations of IRBs and institutionalized science ethics, using bureaucratic theory and, especially, theory related to the development and enactment of rules. We suggest that due to the very character of rules-based systems, improvements in IRB outcomes are unlikely to be achieved through either more or better rules or even by bureaucratic reform. Instead, we suggest that improvements in human subject protection can best be advanced through increased participation. Ours is not a call for more participation by the general public but participation, via “Participant Review Boards” of persons who are eligible, by the protocols of the research in question, to serve as subjects. This provides a level of legitimacy and face validity that cannot be obtained by IRB affiliates, even by “external representatives.” In making these points, we review a recent science ethics controversy, the KKI/Johns Hopkins lead paint study. In spite of being approved by IRBs, the study resulted in a civil lawsuit that reached the Maryland Court of Appeals. The case illustrates the limits of institutionalized science ethics and the bureaucracies created for their enactment. The case also underscores the complex and equivocal nature of the ethical guidelines established under the National Research Act