Learn the Issues
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Using meteorological station data for off-site consequence analyses
For the purpose of the offsite consequence analyses required under 40 CFR Part 68, Subpart B, there are several instances in which data gathered at a local meteorological station may be used to establish the modeling parameters of wind speed, atmospheric stability, temperature, and humidity for the stationary source. How…
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Release scenarios for substances exhibiting flammability and toxicity
Under the hazard assessment requirements in 40 CFR Part 68, Subpart B, an owner or operator must analyze worst-case release scenarios and more likely alternative release scenarios, and must document a five-year accident history. If a regulated substance exhibits characteristics of both toxicity and flammability, should owners and operators consider…
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No trespassing signs restricted access onsite or offsite public receptor
The definition of public receptor is "offsite residences, institutions (e.g., schools, hospitals), industrial, commercial, and office buildings, parks, or recreational areas inhabited or occupied by the public at any time without restriction by the stationary source ..." Offsite is further defined to include "areas within the property boundary [of the…
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Identifying public receptors and property with restricted access
Does public receptor cover only buildings on a property or the entire property? If the owner of the land next to my site restricts access to the land, is it still a public receptor? Public receptors are not limited to buildings. For example, if there are houses near your property…
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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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How many worst-case release scenarios must be analyzed and documented in the RMP?
As a part of the hazard assessment requirements in 40 CFR Part 68, Subpart B, I must analyze worst-case release scenarios and document certain analyses in my risk management plan (RMP). How many worst-case release scenarios must be analyzed, and how many analyses must be specifically documented in the RMP…
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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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Does the distance to endpoint start at the process or stationary source boundary?
When selecting the worst-case release scenario for Program 2 and 3 processes as required by 40 CFR §68.25, a stationary source owner or operator must analyze the release scenario that results in the greatest distance to an endpoint. Does the "greatest distance to an endpoint" refer to the greatest total…
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Do environmental receptors include areas that are not Federal Class I areas?
Do environmental receptors include areas that are not Federal Class I areas under the CAA? Yes. The list of environmental receptors in Part 68 includes areas in addition to those that qualify as Federal Class I areas under CAA section 162. Under Part 68, national parks, monuments, wilderness areas, and…
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Are rivers used for recreation 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 in 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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Distance to endpoint calculations used by RMP*Comp
Does RMP*Comp perform some math or modelling in order to arrive at an endpoint distance, or is it simply interpolating from the tables in the EPA's Offsite Consequence Analysis Guidance (OCA Guidance)? RMP*Comp follows the procedures set out in the OCA Guidance. This means that for some scenarios, the endpoint…
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Redoing calculations if RMP*Comp is updated
Will RMP*Comp be updated? If so, would I have to redo calculations I might already have made with an earlier version? No, you do not have to redo your work if you have already completed your consequence analyses. RMP*Comp is based on the EPA's Offsite Consequence Analysis Guidance (OCA Guidance)…
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What does "control of the same person" mean?
Control of the same person refers to corporate control, not site management. If two divisions of a corporation operate at the same site, even if each operation is managed separately, they will count as one source provided the other criteria are met because they are under control of the same…
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What is the definition of "offsite property damage?"
I am working on the five-year accident history portion of the hazard assessment under the RMP. Section 68.42(a) tells me to include "all accidental releases from covered processes that resulted in deaths, injuries, or significant property damage on site, or known offsite deaths, injuries, evacuations, sheltering in place, property damage…
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Worst-case release scenarios with gases liquified by refrigeration
When evaluating the worst-case release scenario for spills of liquid toxic substances, the owner or operator should assume that the maximum quantity within the vessel or pipe was released instantaneously to form a liquid pool (40 CFR §68.25(d)(1)). For regulated toxic substances that are normally gases at ambient temperature, the…
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Worst-case release from smaller process with larger distance to endpoint
The owner or operator of a stationary source covered by the risk management program regulations must conduct a worst-case release scenario analysis as part of the required hazard assessment (40 CFR §68.25). The worst-case release is defined as the release of the largest quantity of a regulated substance from a…
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Underground storage tank off-site impacts to groundwater, drinking water, or soil
For the worst-case and alternative release scenarios of an underground storage tank, should I consider any impact on groundwater, drinking water, or soil? No. As part of the worst-case and alternative release scenarios, you need to define the offsite impacts to the environment (40 CFR §68.33) by listing the environmental…
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RMP*Comp and emergency response
Can I use RMP*Comp for emergency response? No. It's a planning tool. Many other tools are available for response, including ALOHA. You can learn more by reading CAMEO tools for RMP.
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How did EPA select the list of regulated substances?
The list of regulated substances under the chemical accident prevention provisions is found in 40 CFR Part 68. How did EPA select the substances to be included in this list? The chemical accident prevention provisions promulgated pursuant to Section 112(r) of the Clean Air Act (CAA) are designed to focus…
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What is the content of Part 68, Subpart F and when was it promulgated?
The regulatory text of the June 20, 1996, Risk Management Program Rule ( 61 FR 31668) does not include Subpart F. What is the content of Subpart F and when was it promulgated? Subpart F of 40 CFR Part 68 consists of the regulations concerning the list of regulated substances…