How bureaucracies perceive and respond to technological risk is the subject of this study in organizational theory. The author offers evidence from primary sources such as the testimony of agency officials; agency memoranda; and extensive interviews in Congress, the bureaucracy, and the White House to explain the organizational failures leading to the Three Mile Island and Challenger accidents. She examines the implications of these organizational failures in terms of how organizations communicate about and cope with potential risks to public safety—in hopes of avoiding such disasters in the future.