Organizational climate research has focused on prediction of organizational outcomes rather than on climate as a social-cognitive mediator between environmental attributes and relevant outcomes. This article presents a model specifying that supervisory safety practices predict (safety) climate level and strength as moderated by leadership quality. Using supervisory scripts as proxy of practices, it is shown that script orientation indicative of safely priority predicted climate level, whereas script simplicity and cross-situational variability predicted climate strength. Transformational leadership mitigated these effects because of closer leader-member relationships. Safety climate partially mediated the relationship between supervisory scripts and injury rate during the 6-month period following climate and script measurement. Theoretical and methodological implications are discussed.