Needlestick injuries (NSIs) are a recognized risk for occupationally-related transmission of bloodborne pathogens (BBP). The occurrence of NSIs and BBP exposures among firefighters (FFs) and emergency medical services (EMS) personnel has been documented. The purposes of this study were: 1) to define the problem of NSI among FFs and EMS personnel in a suburban fire department (FD) and identify practices and factors that influence sharps use and safety; 2) design and implement and intervention to promote safer sharps device usage; and 3) to measure the effectiveness of the intervention among FFs and EMS personnel. A multi-phase, mixed methods approach was used that included a diagnosis phase that utilized a mixed methods exploratory design, an intervention period, and a quantitative evaluation phase that used a before and after evaluation design. In the diagnosis phase, data regarding sharps device practices were obtained through a count of discarded sharps devices. Qualitative data regarding sharps practices and factors which influenced those practice were obtained via focus groups. The PRECEDE/PROCEED model (PPM) was used as the theoretical framework for assessment, planning, implementation, and evaluation of an intervention to increase the occurrence of safer sharps device behaviors and decrease the frequency of riskier sharps device behaviors. The evaluation phase included a post-intervention sharps count and a post-intervention survey to assess changes in sharps practices and the impact of the intervention. During the baseline sharps count, 2743 sharps devices were counted and classified according to pre-established categories of safer or risky behaviors for NSI. Altered safety devices on IV stylets were the highest count for unsafe behaviors (n=105), followed by recapped traditional needles (n= 53). A statistically significant increase in risky behaviors was observed in discarded sharps from engines, as opposed to ambulances, among all sharps devices combined (p=0.000) and IV stylets (p=0.000). When comparing advanced life support (ALS) medications to all other medications, a statistically significant increase in unsafe behaviors occurred among all sharps devices combined (p=0.000) and prefilled syringes (p=0.000). Input from eight focus groups of firefighters allowed for identification of multiple themes which guided the development of an intervention. The intervention included distribution of a hands-on training kit and booklet, expansion of an existing required BBP training, and posters to increase awareness regarding NSI prevention. In the evaluation phase, a total of 2178 sharps devices were counted and classified in a post-intervention sharps count. Altered safety devices on IV stylets were the highest count of unsafe behaviors (n=50). Recapped traditional needles were the second highest count of unsafe behaviors (n=27), but experienced an 18.7% drop in frequency when compared to baseline. When comparing riskier behaviors to the pre-intervention baseline sharps count, statistically significant decreases in risky behaviors were observed in all sharps devices combined ( 2=25.71, p=0.000), IV stylets (2=16.87, p=0.000), and traditional needles (=5.07, p=0.024). A post-intervention survey, consisting of 15 Likert scale questions, was returned by 165 out of 383 active field personnel (41.3%). Results indicated high frequencies of strongly agree and somewhat agree responses regarding risk perception; the importance of using safer needle devices; the impact of the intervention on safer needle practices and sharps safety awareness. Critical predisposing, reinforcing, enabling, and environmental factors which influenced sharps device practices were identified. This study identified factors and practices which influenced unsafe sharps device behaviors. Due to the statistically significant decreases in risky behavior in the post-intervention sharps count and the positive responses in the post-intervention survey, it can be concluded that the intervention did positively impact sharps device behavior and reduced the risk of NSI. The implications of the study are numerous and include a need to explore these practices and factors at other fire departments and EMS agencies, address gaps in regulations; promote research targeting FFs and EMS personnel in regard to NSI, and promote a nationwide effort to prevent NSI among emergency responders.