Search Frequent Questions

Filter By:

Active filters:

Remove all filters

Displaying 1 - 15 of 109 results

  • Criteria for selecting alternative release scenarios

    As part of the hazard assessment, owners and operators of Program 2 and Program 3 covered processes must identify and analyze alternative release scenarios (40 CFR §68.28). What criteria should be used when selecting an alternative release scenario? The owner or operator of a stationary source subject to the risk…

    • Last published:

  • Where can I find older NEI data (prior to 2008)?

    The raw data and summaries that are still available (dating back to 1990) can be obtained from the web page https://www.epa.gov/air-emissions-inventories/pollutant-emissions-summary-files-earlier-neis . Starting with 2001 data, a more limited selection of summary files are available.

    • Last published:

  • How do the different parts of particulate matter (PM) fit together?

    The various parts of PM in the NEI are related as follows. PM10-FIL > PM25-FIL because PM10-FIL includes PM25-FIL PM25-PRI = PM25-FIL + PM-CON This equation only applies at the process level. Because some sources only can report PM2.5 (due to test method differences), this equation does not apply to…

    • Last published:

  • How does PM2.5 relate to PM species such as EC, OC, SO4, NO3, PMFINE, and DIESEL-PM25?

    Primary PM2.5 estimates are speciated into the five PM species in the NEI: elemental (black) carbon (EC), organic carbon (OC), nitrate (NO3), sulfate (SO4), and the remainder of PM25-PRI (PMFINE). Diesel engine PM25-PRI and PM10 emissions are also labeled as DIESEL-PM25 and DIESEL-PM10 for mobile source diesel engines. For all…

    • Last published:

  • 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…

    • Last published:

  • 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…

    • Last published:

  • 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…

    • Last published:

  • Administrative controls considered when determining worst-case release quantity

    For the purpose of analyzing the worst-case release scenario required as part of the hazard assessment at 40 CFR Part 68, Subpart B, the worst-case release quantity is identified as the greatest amount held in a single vessel or pipe, taking into account administrative controls that limit the maximum quantity…

    • Last published:

  • Are Mechanical Controls Considered Administrative Controls?

    For the purpose of analyzing the worst-case release scenario required as part of the hazard assessment at 40 CFR Part 68, Subpart B, the worst-case release quantity is identified as the greatest amount held in a single vessel or pipe, taking into account administrative controls that limit the maximum quantity…

    • Last published:

  • 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…

    • Last published:

  • Underground Storage Tanks in SPCC Plans

    If a gas station that has less than 42,000 gallons completely buried oil storage capacity and no aboveground oil storage capacity installs a new aboveground tank with a capacity greater than 1,320 gallons, must the facility’s Spill Prevention, Control, and Countermeasure (SPCC) Plan address the underground storage tanks (USTs) in…

    • Last published:

  • Can I use any previous three year meteorological data for worst case scenario?

    I am trying to complete my worst case release scenario for the Risk Management Plan under §68.25. I understand that I am required to use a wind speed of 1.5 m/s and F atmospheric stability class as specified in §68.22(b), unless I can prove that at no time over the…

    • Last published:

  • Container capacity less than 55 gallons

    Do facilities need to consider containers that are less than 55 gallons for applicability under 40 CFR Part 112? No. The third column of page 47066 of the July 17, 2002 Preamble states that "You need only count containers of 55 gallons or greater in the calculation of the regulatory…

    • Last published:

  • Oil-filled equipment capacity

    When counting against the 1,320 aboveground storage capacity threshold, would operational storage of oil (such as in a hydraulic press) be used? Oil which is contained in equipment is required to be factored into the storage capacity for the facility even though the oil may be only used for ancillary…

    • Last published:

  • If your farm does not have fuel storage that will flow into US waters by a ditch, river, stream, or lake, do you have to prepare a SPCC Plan?

    No. EPA suggests you use a common sense approach. If one of your oil storage tanks leaks, and the spilled oil would not flow into navigable waters or adjoining shorelines, you do not have to prepare a Plan. Remember that you still have the responsibility to clean up any spilled…

    • Last published: