Two studies investigate whether employees viewing discretionary safety activities as part of their job role (termed safety citizenship role definitions, SCRDs) plays an important part in predicting two types of safety violation: routine violations conceptualized as related to an individual’s available cognitive energy or ‘effort’; and situational violations, which are those provoked by the organization (Reason, 1990). Study 1 showed SCRDs predicted situational violations only, and partially mediated the relationships between Perceived Management Commitment to Safety (PMCS) and work engagement with situational violations. These findings add to those by Hansez & Chmiel (2010), showing that routine and situational violations have predictors that differ. Study 1 findings also extend research reported by Turner, Chmiel and Walls (2005), by showing that the effect of Job Control on SCRDs was mediated by both PMCS and work engagement. In study 2, participation in discretionary safety activities (safety participation) fully mediated the relationship between SCRDs and situational violations. The link between SCRDs and routine violations was non-significant and, strikingly, so was the link between safety participation and routine violations. These results support the view that processes involving SCRDs and safety participation are not cognitive-energetical in nature. In addition, study 2 findings extend previous work by Neal & Griffin (2006) by showing that SCRDs and safety knowledge partially mediated relationships between safety motivation and safety participation, whereas the direct effect of safety motivation on safety participation was non-significant. The results from both studies support the view that SCRDs are important in predicting situational violations.