PROJECT ABSTRACT Firearm violence is associated with access to firearms at both the individual and ecological levels. Preventing firearm access by those at significant risk of violence is a logical strategy to reduce firearm homicide, firearm suicide, and nonfatal firearm violence. Extreme Risk Protection Order (ERPO) laws provide a civil court option for temporarily removing firearms from, and preventing purchase by, high-risk individuals. To date there are no empirically developed guidelines on how law enforcement agencies are to implement ERPO, including firearm removal from newly prohibited individuals. This project will develop ERPO implementation guidelines through the use of community-based participatory research with a focus on communities that experience high rates of firearm violence. The research will unfold through a process that will be responsive to feedback about ERPO from impacted communities about the need for ERPO implementation processes that recognize the fractured relationships between their communities and law enforcement, and are trained on how to constructively interact with people experiencing mental illness or a suicidal crisis. We will develop an implementation strategy for implementing ERPO in a just and equitable manner. Our aims are as follows: 1. Identify counties in Florida and Maryland where ERPO use is high and describe how ERPO is being used in those counties. 2. Document, understand, and examine the perspectives of impacted communities, prior respondents to ERPO, and implementers about ERPO and its implementation. 3. Develop an Implementation Strategy for Impacted Communities centering on just and equitable implementation of ERPO. 4. Pilot the ERPO Implementation Strategy for Impacted Communities and measure the acceptability, feasibility, and sustainability of the Strategy among implementing stakeholders. 5. Revise and disseminate the implementation guide to interested stakeholders around the United States. This project is responsive to the CDC’s RFA-CE-22-004 under Funding Option B. We will address Objective One: Research to improve understanding of firearm injury and inform the development of innovative and promising prevention strategies. An accomplished group of gun violence prevention researchers—including national leaders in the field and those on the front lines of providing information and technical assistance to policymakers and actors in the ERPO process—has come together for this innovative and timely research. This project’s use of community-based participatory research and a framework of just and equitable ERPO implementation will be invaluable to jurisdictions as they seek to implement this firearm violence reduction tool.