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  • 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.

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  • 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…

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  • 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…

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  • Can a facility divide a process when assigning program levels?

    My process includes a series of interconnected units, as well as several storage vessels that are co-located. Several sections of the process could qualify for Program 1. Can I divide my process into sections for the purpose of assigning Program levels? No, you cannot subdivide a process for this purpose…

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  • If a stationary source has processes ineligible for Program 1, are all processes ineligible?

    If a stationary source has several processes that are covered under 40 CFR Part 68, and some of those processes have had an accidental release within the past five years (effectively making those processes ineligible for Program 1 status), are the individual processes from which no accidents have occurred also…

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  • If a covered process has an accident, when does it lose eligibility for Program 1 status?

    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). Those criteria include a requirement that the process cannot have had an accidental release of a regulated substance that led to offsite death, injury…

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  • Applicability of program levels and prevention program requirements for co-located vessels

    I have a tank with 1,000,000 pounds of toluene diisocyanate (TDI), which is covered under the RMP rule, but not under OSHA PSM. Considered by itself, the TDI would be Program 2 for EPA. The tank, however, is close to equipment that has chlorine above the applicable threshold and is…

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  • Changing from a Program 2 or 3 process to a Program 1 process

    If five years have passed since the last accident involving a covered process, and that process meets the other two requirements identified under 40 CFR §68.10(b) for Program 1 eligibility, could that process become a Program 1 process even if it had previously been identified as a Program 2 or…

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  • Where can I download hourly emissions data from continuous monitoring?

    Hourly emissions data files are available from the Clean Air Markets Division of EPA, collected as part of 40 CFR Part 75. The download location has changed in February, 2023. The new location is https://campd.epa.gov/data/bulk-data-files . Once on this new site, use the menu (at the left) and the Keyword…

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  • Tier2 Submit software and confidential chemical location information

    When using EPA’s Tier2 Submit software to comply with the annual Hazardous Chemical Inventory reporting requirement under the Emergency Planning and Community Right-to-Know Act (EPCRA) §312, how can a person withhold confidential chemical location information from disclosure to the public? In order to fulfill the proper reporting under EPCRA, a…

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  • Do states require extra Tier II information?

    Do states require additional information on the Tier II report? How can I find out about the state data requirements? Some states do want additional Tier II information; contact your state Tier II administrator to learn specific details. Tier2 Submit includes fields for the additional information requested or required by…

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  • No Street Address Availability Tier II Reporting

    Pursuant to 40 CFR 370.42(d) , Tier II chemical inventory information must include the complete name and address of the location of the facility (including the full street address or state road, city, county, State and zip code), latitude and longitude. If a facility does not have a street address…

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  • What sources make up the Tier 1 categories used in the emissions trends?

    Tier 1 categories are assigned by source classification codes (SCCs) that are the most specific processes available in the NEI. The latest SCC list with the Tier 1 assignments can be downloaded from the EPA SCC website in Comma Separate Values (CSV) format.

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  • What is the cause of the large decrease in electric utility emissions, particularly sulfur dioxide, starting in 1995?

    SO2 emissions reductions from utilities during this time are primarily attributed to the impacts of the acid rain program. As described on EPA’s Acid Rain Program web page, Phase 1 of this program began in 1995 and affected 263 units at 110 most coal-burning electric utility plants in 21 eastern…

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  • Assigning program level 1 if a public receptors is just beyond distance to endpoint

    Our distance to the endpoint for the worst-case release is 0.3 miles. The nearest public receptor is 0.32 miles away. What tools are available to document that the public receptor is beyond the distance to the endpoint so we can qualify for Program 1? The results of any air dispersion…

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