This study examines the attitudinal impact of an Extended Parallel Process Model (EPPM)-based training curriculum on local public health department (LHD) workers' willingness to respond to representative public health emergency scenarios. Data are from 71 U.S. LHDs in urban and rural settings across nine states. The study explores changes in response willingness and EPPM threat and efficacy appraisals between randomly assigned control versus intervention health departments, at baseline and 1 week post curriculum, through an EPPM-based survey/resurvey design. Levels of response willingness and emergency response-related attitudes/beliefs are measured. Analyses focus on two scenario categories that have appeared on a U.S. government list of scenarios of significant concern: a weather-related emergency and a radiological "dirty" bomb event (U.S. Department of Homeland Security, 2007). The greatest impact from the training intervention on response willingness was observed among LHD workers who had low levels of EPPM-related threat and efficacy perceptions at baseline. Self-efficacy and response efficacy and response willingness increased in intervention LHDs for both scenarios, with greater response willingness increases observed for the radiological "dirty" bomb terrorism scenario. Findings indicate the importance of building efficacy versus enhancing threat perceptions as a path toward greater response willingness, and suggest the potential applicability of such curricular interventions for boosting emergency response willingness among other cadres of health providers.