Blood-borne pathogens threaten all individuals involved in emergency health care. Despite recommendations by the Centers for Disease Control and the American College of Emergency Physicians, documented compliance with universal precautions in trauma resuscitation has been poor. The purpose of this study was to determine the factors that predispose to noncompliance with barrier precautions at a level I trauma center. Videotapes of trauma resuscitations performed during 1 month (n = 66) were reviewed. Full compliance with barrier precautions was documented in 89.1% of health care workers. Of the noncompliant health care workers, 50.7% were emergency department personnel and 47.8% were first responders to the trauma resuscitation area. Barrier precaution compliance improved from 62.5% to 91.8% with prenotification of patient arrival. Immediate access to barrier equipment is essential for all potential in-hospital first responders. Prehospital communication systems should be optimized to ensure prenotification.