In its final report on the causes of the 2010 Tesoro refinery explosion in Anacortes, Wash., that killed seven workers, the Chemical Safety & Hazard Investigation Board (CSB) has removed its draft recommendations for a new “safety case” regulatory scheme for U.S. refineries. A safety case approach is used in several countries and requires companies to work with regulators to develop regulatory requirements. Once developed, the performance-based regulatory system is overseen by government regulatory inspectors. The safety case was a key part of earlier draft recommendations, but two of CSB’s three current members opposed it, as did employers and the United Steelworkers Union. The final report, which unanimously cleared the board on May 1, recommends that inherently safer systems analysis be required whenever possible and calls for several process safety improvements. It also notes that CSB is still considering a safety case approach in some of its ongoing investigations. The actual causes of the Tesoro accident—piping corrosion and Tesoro safety failures—remain as stated in earlier drafts.