The document summarizes Dianne Vaughn's theory of normalization of deviance, which proposes that people exposed to deviant behavior in an organizational setting will gradually adapt to see that deviance as the norm. It uses the examples of Enron and the Challenger space shuttle disaster to illustrate how normalization of deviance can emerge from leadership or organizational culture tolerating illegal or risky behavior. In both cases, members of the organizations became so accustomed to deviant practices that they no longer saw the behaviors as deviant, leading to disasters. The theory suggests leadership must take responsibility for ensuring an organizational culture does not develop that allows deviant behaviors to be seen as acceptable.