Studies show significant association between cancer risk and being a firefighter. After exposure to even routine firefighting, firefighters' bunker gear often contains carcinogens that may be absorbed through contact or inhaled through off-gassing, thereby increasing cancer risk. Awareness of increased cancer risk has given rise to policies and practices focused on gear cleaning and decontamination processes to decrease risk; yet, these efforts are in their infancy and tend to be somewhat piecemeal in nature. This study presents a theory-based communication intervention tailored to the unique context of high-reliability organizations (HROs). The intervention focused on increasing postfire decontamination behaviors to reduce exposure to carcinogens among firefighters. Results of the intervention across 14 fire stations from 2 fire departments in South Florida show significant increases in attitudes, norms, and self-efficacy, decreases in perceived barriers, and increased intention to engage in decontamination processes. While the intervention was highly successful in both fire departments, there were significant differences in between organizations; attitudes perceived norms, and barriers to gear cleaning remained significantly different. This highlights the need to examine the specific context of the organization in designing interventions. In line with previous research on HROs, regression models showed that norms and self-efficacy are the strongest predictors of current behavior. However, postintervention, attitudes emerge as the strongest predictor of future behavior. The results of this study provide valuable evidence for utilizing theoretical elements in message design for interventions in HROs, and of the importance of designing communication for specific sites of intervention.