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  • Flammable event with different time duration

    What if a flammable event has a different time duration than the 5 kw/m2 for 40 seconds? EPA recognizes that flammable events may occur for a different amount of exposure time. Therefore, the owner or operator should determine the distance to an equivalent exposure - e.g. if the flammable event…

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  • Definition and data sources of "environmental receptor"

    The Risk Management Program rule requires owners or operators of covered processes to define in the risk management plan (RMP) the potential offsite public and environmental receptors within the impact range of identified worst case and alternative release scenarios. What is the definition of "environmental receptor"? What data sources are…

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  • Worst-case Release Scenario for Separate, Interconnected Vessels

    Pursuant to the risk management program regulations, facilities must perform an offsite consequence analysis for the worst-case release scenario. Do the quantities of two separate vessels that are interconnected with a closed valve need to be aggregated for the worst-case release scenario analysis? No. Worst-case release is defined as the…

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  • Worst-case release scenarios for toxics and flammables represented by Program 2 or 3 processes

    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…

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  • Non-residential population in off-site consequence analyses

    Must an owner or operator include in their risk management plan (RMP) estimates of the non-residential population when defining off-site impacts for the off-site consequence analysis? Owners or operators are required to note in the RMP the presence of any major institutions (i.e., schools, hospitals, or prisons), public recreational areas…

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  • Qualifier "solution" in the listing for formaldehyde

    Formaldehyde is listed in 40 CFR 68.130 with the qualifier "solution." Does the qualifier refer only to mixtures of formaldehyde and water, or does it apply to any liquid mixture containing formaldehyde? Formaldehyde (CAS No. 50-0-0) is listed with the qualifier "solution" because pure formaldehyde has a tendency to polymerize…

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  • Part 68 regulations compared to other CAA provisions

    Do the risk management program regulations at 40 CFR Part 68 place additional requirements on stationary sources that are currently in compliance with all other provisions of the Clean Air Act (CAA)? Yes. Owners and operators of stationary sources who meet the applicability criteria at 40 CFR §68.10 must comply…

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  • Are barracks and family housing units on military bases considered public receptors?

    Barracks are not considered public receptors, family housing units are. Public receptors include any "offsite residences ... inhabited or occupied by the public at any time without restriction by the stationary source where members of the public could be exposed to toxic concentrations, radiant heat, or overpressure, as a result…

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  • Are on-site areas with unrestricted access considered public receptors?

    A process covered under 40 CFR Part 68 is eligible for Program 1 requirements if it meets all of the criteria listed at 40 CFR §68.10(b). One of those criteria is that the distance to a toxic or flammable endpoint for a worst-case release assessment is less than the distance…

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  • Are areas occupied solely by employees considered public receptors?

    When analyzing off-site consequences for the purpose of a worst-case or alternative release scenario under the risk management program regulations (40 CFR Part 68), are areas occupied solely by employees at the source considered to be public receptors? No. Such areas at the stationary source are not to be included…

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  • Why do the risk management program regulations only apply to stationary sources?

    Why have transportation activities been exempted from compliance with the risk management program regulations at 40 CFR Part 68? Why do these regulations apply only to stationary sources? While EPA agrees that industry, local planners, and first responders need to recognize the public safety hazards associated with transportation, the Clean…

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  • Do the quantities of interconnected vessels need to be aggregated for the worst-case release scenario analysis?

    Pursuant to the risk management program regulations, facilities must perform an offsite consequence analysis for the worst-case release scenario. Do the quantities of two separate vessels that are interconnected with a closed valve need to be aggregated for the worst-case release scenario analysis? No. Worst-case release is defined as the…

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  • Active mitigation systems (e.g., scrubbers) and alternative release scenarios

    I run a wastewater treatment plant that is subject to the risk management program regulations in 40 CFR Part 68 for a covered process containing chlorine. A chlorine scrubber system at the plant is designed to prevent any possible releases from reaching a toxic endpoint offsite. How does this active…

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  • Threshold determination for a single process with oleum and sulfur trioxide

    Oleum, which is a mixture of sulfuric acid and sulfur trioxide, is listed as a regulated toxic substance in 40 CFR §68.130. Sulfur trioxide is also listed individually as a regulated toxic substance. If a single process consists of one vessel containing oleum and one vessel containing sulfur trioxide, must…

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  • Will the general duty clause be delegated?

    The general duty clause (CAA section 112(r)(1)) is not included in Part 68 and, therefore, will not be delegated to states that have taken implementation of the RMP program. States, however, may adopt their own general duty clause under state law.

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