According to a joint guidance document released by the Occupational Safety and Health Administration (OSHA) and the National Institute for Occupational Safety and Health (NIOSH), both staffing agencies and host employers (clients of staffing agencies) are responsible for providing and maintaining a safe and healthy work environment for contingent workers. Collaborative and interdisciplinary (e.g., epidemiology, occupational psychology, organizational science, economics, law, management, sociology, labor health and safety) research and intervention efforts are needed to protect and promote the occupational safety and health of contingent workers.