Process hazard analyses (PHAs) usually focus on major hazards-fires, explosions, and toxic releases, Traditional PHA methods, such as the Hazard and Operability (HAZOP) study and What-If analysis, often include scenarios for other hazard types, such as operability problems, Sometimes, this may be desired, but not always. There is a need for a PHA technique that directly and exclusively addresses major process hazards. Such hazards are realized when process containment is lost, Therefore, the method proposed here uses a categorization scheme to guide brainstorming of initiating events that can result in fires, explosions, or toxic releases. It provides a more efficient and, likely, more complete, identification of major hazard scenarios than current PHA methods.