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  • Quantity of a regulated substance in an aqueous solution

    When using RMP*Comp to conduct an offsite consequence analysis (OCA), a facility must specify the quantity released. What quantity should be entered for a regulated toxic substance in an aqueous solution, the total quantity of the aqueous solution or just the quantity of the toxic substance? The entire quantity of…

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  • Must I anticipate a specific cause for the worst-case scenario for a toxic substance?

    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 § 68.25(c) and (d). Anticipated causes of the release…

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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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  • 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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  • 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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  • Can you explain who has authority over the active mine vs the Superfund site?

    The Montana Department of Environmental Quality has regulatory authority over the active mine. EPA is the lead agency for the Silver Bow Creek/Butte Area Superfund Site and works in consultation with MDEQ to ensure the cleanup of the Site.

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  • Where can I go to learn more?

    PitWatch.org is the online home of the Berkeley Pit Public Education Committee. This volunteer committee educates residents, students, and the public about the environmental management of the Berkeley Pit.  Information includes the geology, hydrology, current events, and ongoing academic research associated with the Berkeley Pit. This committee frequently shares their…

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  • When will construction begin in the Silver-Bow Creek Corridor?

    Construction in the Silver Bow Creek corridor began in 2024 with the Grove Gulch Project.

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