Since experience and research in the field of disaster mental health is a key to understanding risks for human service workers in responding to workplace violence or terrorism, this chapter begins with explanations of the basic principles in this field. The chapter then discusses how to prepare, train, and support human service workers, with attention to preventing "compassion fatigue" and "burnout." The section on organizational preparation for human service workers addresses organizational commitment to mitigating the psychological impact of workplace violence, preparation of an organizational mission statement that emphasizes workplace safety, and the importance of working as a team. The section on training human service workers to respond to workplace terrorism focuses on training the workers for their roles and for performing self-care, stress management, and the prevention of "compassion fatigue." The chapter suggests topics that should be covered in stress-management training, and stress-management techniques are listed. Suggestions are also offered for how supervisors can help human service workers deal with the stress of providing constant service to people desperate to have their needs met. Nineteen strategies of self-care for human service workers are outlined as well. The chapter concludes with a list of suggested questions for use in a small-group debriefing of human service workers at the end of a particular assignment. 73 references