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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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  • Hot Work Definition and Requirements

    Facilities subject to the Program 3 Prevention Program requirements in 40 CFR Part 68 must include in their Risk Management Plan the date of the most recent review or revision of hot work permit procedures in Section 7.13. What is considered hot work and what are the requirements related to…

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  • Do I have to conduct incident investigations of releases resulting from theft?

    The incident investigation provisions of 40 CFR Part 68 (§§68.60 and 68.81) require facilities to investigate incidents that resulted in or could reasonably have resulted in a catastrophic release. Are covered facilities required to perform incident investigations of releases resulting from theft of covered substances, such as anhydrous ammonia? If…

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  • Do Program 1 processes have to complete a process hazard analysis?

    Do owners or operators of Program 1 processes have to complete a process hazard analysis? No. The Program 1 requirements do not include a process hazard analysis (40 CFR §68.12(b)). Program 3 processes require completion of a process hazard analysis (40 CFR §68.12(d)(3)) while Program 2 processes must complete a…

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  • Is a hazard review synonymous with a process hazard analysis (PHA)?

    The prevention program requirements under 40 CFR Part 68, Subparts C and D, include hazard reviews and process hazard analyses. Is a hazard review synonymous with a process hazard analysis (PHA)? No. A hazard review is different from a PHA. A hazard review is part of the Program 2 prevention…

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  • How often must compliance audits be performed?

    How often must owners or operators of stationary sources subject to the risk management program regulations perform compliance audits? The regulations at 40 CFR §§68.58(a) and 68.79(a) state that owners or operators must certify that they have evaluated compliance with the applicable prevention program provisions at least once every three…

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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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  • Does compliance under OSHA's PSM demonstrate compliance with the risk management program?

    The Clean Air Act Amendments of 1990 (CAAA) mandated the Occupational Safety and Health Administration (OSHA) to develop a regulatory program to protect workers from the risk of accidents that involve hazardous chemicals. OSHA promulgated its Process Safety Management Standard (PSM) on February 24, 1992 (57 FR 6356), codified at…

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