The Institute of Medicine (IOM) Committee to Evaluate Measures of Health Benefits for Environmental, Health, and Safety Regulation held its fourth meeting on April 5-6, 2005, in Keck 101. The first day was open to the public. During this session, people heard presentations of the three case studies of cost-effectiveness analysis of the Environmental Protection Agency (EPA), Food and Drug Administration (FDA), and the National Highway Transit System Administration (NHTSA) regulations prepared by the Committee in collaboration with federal agency staff. After 3:30 PM on April 5th, the meeting became a closed session that continued on April 6th.