A stationary source subject to the risk management program regulations at 40 CFR Part 68 comprises multiple Program 2 and Program 3 covered processes. The owner or operator must do a single worst-case release analysis to represent toxic regulated substances and a single worst-case release analysis to represent flammable regulated substances (40 CFR §68.25(a)(2)). Could the worst-case scenario for a toxic substance involve a Program 2 process while the worst-case scenario for a flammable substance involves a Program 3 process, and vice versa?

Yes. For the purpose of the hazard assessment requirements of 40 CFR Part 68, Subpart B, no distinction is made between Program 2 and Program 3 processes. The worst-case release scenario for toxic substances can be represented by either a Program 2 or a Program 3 process, and the worst-case release scenario for flammable substances can also be represented by either a Program 2 or a Program 3 process.