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EPA 'clarifies' new source review concept of aggregation, and withdraws debottlenecking NSR proposal

Congress established the New Source Review (NSR) program as part of the 1977 Clean Air Act Amendments and modified it in the 1990 Amendments. NSR is a preconstruction permitting program that serves two important purposes. First, it ensures the maintenance of air quality standards when factories, industrial boilers, and power plants are modified. In areas that do not meet the national air quality standards, NSR ensures that new emissions from modifications do not adversely impact ambient air quality, thereby slowing progress toward cleaner air. In areas that meet the ambient standards, NSR ensures that additional emissions from modifications do not put air quality at risk. Second, the NSR program ensures that state of the art control technology is installed at existing plants that are undergoing a major modification. To help put this in context, under the CAA, there are several broad categories of emissions from stationary sources which are subject to a variety of requirements. These are generally known as "existing sources", "new source", and a "modified source". 42 U.S.C. Section 7411(a); 40 C.F.R. Section 60.1. Existing, new, and modified sources are regulated through State Implementation Plans (SIPs). New and modified sources are generally subject to national standards promulgated by EPA. 42 U.S.C. Section 7411; 40 C.F.R., Part 60. States generally develop standards for existing sources using those SIP procedures established by EPA regulations. 42 U.S.C. Section 7411(d); 40 C.F.R., Part 62. Since a "major modification" almost always triggers additional permitting requirements (and costs) [even some minor modifications can trigger the same requirements], EPA's current regulations define what is included in a the concept of a modification: "The phrases modification or modified source mean any physical change in, or change in the method of operation of, a stationary source which increases the emission rate of any pollutant for which a national standard has been promulgated under part 50 of this chapter or which results in the emission of any such pollutant not previously emitted, except that: (1) Routine maintenance, repair, and replacement shall not be considered a physical change, and (2) The following shall not be considered a change in the method of operation: (i) An increase in the production rate, if such increase does not exceed the operating design capacity of the source; (ii) An increase in the hours of operation; (iii) Use of an alternative fuel or raw material, if prior to the effective date of a paragraph in this part which imposes conditions on or limits modifications, the source is designed to accommodate such alternative use." 40 C.F.R. Section 52.01(d). In September 14, 2006, EPA put forth a proposal that sought to "clarify" how to consider emissions increases and decreases when determining whether the modification is "major", thereby triggering NSR applicability for that modification. One of the concepts proposed was called debottlenecking. Debottlenecking referred to how emissions from units upstream and downstream from the unit(s) undergoing a physical or operational change (a modification) are included in the calculation of an emissions increase for the project. In light of adverse comments on the proposal, EPA announced it is withdrawing this aspect of the 2006 proposal. See EPA has also decided to not go forward with another concept, "project netting". See The one EPA concept to survive, and which EPA has now decided to proceed with, is referred to as "aggregation". Fundamentally, the concept is that a facility does not have to combine emissions from two or more modifications to a facility for the purpose of figuring out whether the NSR permitting program applies unless those modifications are "substantially related" either from an economic or technical standpoint. Furthermore, this final rule specifies that modifications cannot be grouped together based on timing alone (e.g., done simultaneously). To be aggregated, modifications are required to have more in common than just supporting the plant's overall basic function, and sources and permitting authorities are allowed to presume that plant modifications that are separated by three or more years are not substantially related, unless they can prove otherwise. Importantly, the change is NOT a rule change; it is an interpretation of existing regulations. Given the vague language of the "interpretation", it is likely to be subject to much litigation as challenges are raised when a facility claims that NSR is not applicable to its modifications. For further information on aggregation, see

  • Implementation of the New Source Review (NSR) Program for Particulate Matter Less Than 2.5 Micrometers (PM2.5); Final Rule To Stay the Grandfathering Provision for PM2.5

    ACTION: Final rule for 40 CFR Part 52

    SUMMARY: In this final action, EPA is issuing a stay, for nine months, on the "grandfathering" provision for particulate matter less than 2.5 micrometers (PM2.5) requirements in the Federal Prevention of Significant Deterioration (PSD) program. The grandfathering provision was added to the Federal PSD regulations on May 16, 2008, as part of the final rule titled, "Implementation of the New Source Review (NSR) Program for Particulate Matter Less Than 2.5 Micrometers (PM2.5)." This stay follows an administrative stay, which was in effect from June 1, 2009, until September 1, 2009, on the same provision. We believe this additional stay will provide sufficient time for EPA to propose, take public comment on, and issue a final action concerning the repeal of the grandfathering provision for PM2.5 in the Federal PSD program.

    DATES: Effective September 22, 2009, 40 CFR 52.21(i)(1)(xi) is stayed for a period of nine months, until June 22, 2010.

    Docket: All documents in the docket are listed in the index. Although listed in the index, some information is not publicly available, e.g., CBI or other information whose disclosure is restricted by statute. Certain other material, such as copyrighted material, is not placed on the Internet and will be publicly available only in hard copy form. Publicly available docket materials are available either electronically through or in hard copy at the EPA Docket Center, Public Reading Room, EPA West, Room 3334, 1301 Constitution Ave., NW., Washington, DC, 20460. The Public Reading Room is open from 8:30 a.m. to 4:30 p.m., Monday through Friday, excluding legal holidays. The telephone number for the Public Reading Room is (202) 566-1742, and the telephone number for the Air Docket is (202) 566-1744.

    FOR FURTHER INFORMATION CONTACT: Mr. Dan deRoeck, Air Quality Policy Division, (C504-03), U.S. Environmental Protection Agency, Research Triangle Park, NC 27711; telephone number (919) 541-5593; fax number (919) 541-5509; or e-mail address:

    [R]   74 FR 48153 -- Sep. 22, 2009               EPA source: or