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Worst case release scenario for toxic and flammable substances in same Program 1 process

Under the risk management program regulations in 40 CFR Part 68, if a Program 1 process contains a threshold amount of both a regulated toxic substance and a regulated flammable substance, should a worst case release scenario be analyzed for each of the substances in the process?

Yes, a worst case release scenario must be analyzed for each regulated toxic and flammable substance above the threshold. This analysis will serve two purposes: 1) to demonstrate that no release from that process would reach a public receptor as required in 40 CFR §68.10(b)(2); and 2) to determine the one "worst" worst case release scenario that results in the greatest distance to an endpoint, which must be reported in the RMP.