Protecting 18 million United States health care workers from infectious agents - known and unknown - involves a range of occupational safety and health measures that include identifying and using appropriate protective equipment. The 2009 H1N1 influenza pandemic and the 2014 Ebola virus outbreak in West Africa have called raised questions about how best to ensure appropriate and effective use of different kinds of personal protective equipment such as respirators, not only to promote occupational safety but also to reduce disease transmission. The Use and Effectiveness of Powered Air Purifying Respirators in Health Care is the summary of a workshop convened by the Institute of Medicine Standing Committee on Personal Protective Equipment for Workplace Safety and Health to explore the current state of practices and research related to powered air purifying respirator (PAPRs) and potential updates to performance requirements. Presentations and discussions highlighted current health care practices using PAPRs and outlined the research to date on the use and effectiveness of PAPRs in health care settings with a focus on the performance requirements. The Use and Effectiveness of Powered Air Purifying Respirators in Health Care focuses on efficacy, current training, maintenance, supplies, and possible enhancements and barriers to use in inpatient, clinic, nursing home, and community (home) settings. This report also explores the strengths and weaknesses of using various approaches to health care PAPR standards.