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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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  • What is a farm for purposes of the SPCC Rule?

    In the December 2006 amendments to the SPCC Rule, EPA defined a farm as "a facility on a tract of land devoted to the production of crops or raising of animals, including fish, which produced and sold, or normally would have produced and sold, 1,000 or more of agricultural products…

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  • Examples of an agent of a Professional Engineer

    Except as provided in 40 CFR §112.6 for qualified facilities, a Professional Engineer (PE) or an agent of the PE must visit and examine the facility before the PE certifies an SPCC Plan (40 CFR §112.3(d)). What are some examples of an agent of a PE? An agent of a…

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  • What is considered bulk oil storage capacity?

    The revised rule recognizes that oil is sometimes stored in bulk and sometimes used operationally. A bulk storage container is any container storing oil at a facility. Bulk oil storage containers may include, but are not limited to tanks, containers, drums, and mobile or portable totes. Operational use includes oil-filled…

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  • Mobile fuel tanker as a facility

    Is a non-transportation related mobile fuel tanker with more than 55 gallons located near a 55 gallon drum storage area considered a facility? Perhaps. "Facility" is defined in Part 112 to mean "any mobile or fixed, onshore or offshore building, structure, installation, equipment, pipe, or pipeline (other than a vessel…

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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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  • 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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  • 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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