When analyzing the worst-case scenario for regulated toxic substances, must I anticipate a specific cause (e.g., fire, explosion, etc.) of the scenario?
No. The worst-case analysis for a release of regulated toxic substances must conform to specific assumptions as identified in ยง 68.25(c) and (d). Anticipated causes of the release will not affect the analysis, and are not required. A specific cause may be considered in analyzing the alternative release scenarios although it is not a requirement.
Source: https://www.epa.gov/rmp/must-i-anticipate-specific-cause-worst-case-scenario-toxic-substance