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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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  • Do settlement communications, such as past “agreements in principle,” impact the implementation of the final Consent Decrees?

    The parties are bound by the terms of the various final, publicly available consent decrees. These consent decrees were made available for public comment before they were finalized and entered by the Court. Past settlement communications and documents created in the course of settlement discussions have been incorporated (or not)…

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  • What is the Confidentiality Order?

    The Confidentiality Order (Order) is a court order entered by the Federal District Court for the District of Montana (Court) on August 8, 2002, and amended by the Court on December 31, 2003, that applies to Superfund settlement negotiations in the Clark Fork River Basin, including the following sites: Silver…

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  • How does EPA ensure that the potentially responsible parties complete their work?

    All cleanup activities performed by the PRPs are subject to enforcement instruments (i.e., consent decrees or administrative orders) that provide for EPA approval of all deliverables and oversight of all work performed by the PRPs.

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  • Why is the Confidentiality Order important?

    The Confidentiality Order (Order) has been, and continues to be, effective in assisting the parties in reaching settlements under the framework established by the Court in US v. ARCO and still pending in court – six consent decrees to date have been entered since the Order was issued. There are…

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  • What is included in the emissions “Tiers”?

    The Tiers are assigned by a Source Classification Code (SCC), which has the most detail about the emissions processes that generate the emissions. The full list of SCCs, their associated Tiers, and the SCC descriptions is available online at https://ofmpub.epa.gov/sccwebservices/sccsearch/ .

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  • Why were the consent decree negotiations under a confidentiality order?

    The confidentiality order was issued by the federal district court in 2002 to encourage and facilitate settlement negotiations. The court determined that the confidentially order was appropriate to ensure that the parties were afforded the opportunity to engage in frank, open discussion so that litigation could be settled promptly and…

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  • What does an annual emissions value in the NEI represent (one year or multiple years)?

    The NEI provides total annual emissions for a single year.

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  • What projects has EPA been involved with in Butte related to the Superfund site?

    A variety of actions and activities have been implemented to address the contamination in Butte, including: Assessments of risk have been conducted to quantify actual and potential human health risks due to potential exposure to tailings, waste rock, yard soils, indoor dust, attic dust, mercury vapor, surface water, and ground…

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  • What does the Confidentiality Order not cover?

    The Order does not apply to technical documents, discussions, and meetings concerning the implementation of the consent decrees that occur after the Court entered the consent decrees.

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  • What work are the potentially responsible parties required to complete at Butte Priority Soils Operable Unit?

    EPA will conduct oversight in consultation with the Montana Department of Environmental Quality (MDEQ) on all work to be implemented by Atlantic Richfield and Butte-Silver Bow County. Atlantic Richfield will perform work in the Butte Reduction Works, Northside Tailings, Diggings East, Buffalo Gulch, East Buffalo Gulch, and Grove Gulch areas…

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  • What are the units of NEI emissions data?

    NEI emissions values represent total annual emissions for the inventory reporting year. Criteria air pollutants and precursors (CAPs) are reported in short tons per year , and hazardous air pollutants (HAPs) are reported in lbs per year .

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  • What is the definition of VOC?

    There is a regulatory definition of VOC. It is found in 40 CFR 51.100. CFR - code of federal regulations. The definition relates to the intent and requirements of the Clean Air Act. Excerpt from “Volatile Organic Compounds” Definition per 40 CFR Part 51.100(s): " Volatile organic compounds (VOC) means…

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  • What does "NEC" stand for in the emissions sectors?

    NEC means “not elsewhere classified” and includes SCCs that are not assigned to any of the other specific industrial process sectors. If you look at the SCC code table available at the SCC web site and filter on the Sector name that includes “NEC”, you can see the type of…

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