What organization is OSHA's sister agency that focuses on research and training and also conducts Health Hazard Evaluations?

NiOSH, or the National Institute for Occupational Safety and Health, is the U.S. federal agency responsible for conducting research and making recommendations for the prevention of work-related injury and illness.

It might be considered a sister agency of OSHA, since both were created by passage of the Occupational Safety and Health Act.