Using the piloted LMC protocol, we will conduct the first randomized, controlled trial (RCT) of the effectiveness of ED-based LMC on firearm and medication storage. The proposed RCT, to be conducted in five Colorado hospitals, will test whether parents of at-risk adolescents who are treated in hospitals that have (vs. have not yet) implemented our LMC protocol are more likely to store household firearms and medications safely. In addition, we will conduct in-depth, qualitative interviews with parents who have received LMC counseling to better understand those factors that affect parents' willingness and ability to make changes to firearm and medication storage. We will also conduct qualitative interviews with clinicians to understand factors affecting clinician engagement in LMC.