This report presents recommendations for postexposure interventions to prevent hepatitis B virus, hepatitis C virus, or HIV infections and tetanus in persons wounded in bombings or events causing mass casualties. During such events, wounded persons may be exposed to blood, body fluids, or tissue from other injured persons, putting them at risk for bloodborne infections. The report was developed in consultation with experts in immunization and other prophylactic interventions against bloodborne and other infections, physicians who specialize in acute injury-care medicine (trauma and emergency medicine), and local, state, and federal public health epidemiologists. It adapts existing recommendations on the use of immunization and postexposure prophylaxis in response to occupational and nonoccupational exposures to blood borne pathogens in the United States. It also draws on guidance and practices developed previously and in use in the United Kingdom and Israel.