(v) A decrease in actual emissions is creditable only to the extent that: (a) The old level of actual emissions or the old level of allowable emissions, whichever is lower, exceeds the new level of actual emissions; (b) It is federally enforceable at and after the time that actual construction on the particular change begins; (c) The reviewing authority has not relied on it in issuing any permit under regulations approved pursuant to 40 CFR 51.18; and (d) It has approximately the same qualitative significance for public health and welfare as that attributed to the increase from the particular change. (vi) An increase that results from a physical change at a source occurs when the emissions unit on which construction occurred becomes operational and begins to emit a particular pollutant. Any replacement unit that requires shakedown becomes operational only after a reasonable shakedown period, not to exceed 180 days. 7. Emissions unit means any part of a stationary source which emits or would have the potential to emit any pollutant subject to regulation under the Act. 8. Secondary emissions means emissions which would occur as a result of the construction or operation of a major stationary source or major modification, but do not come from the major stationary source or major modification itself. For the purpose of this Ruling, secondary emissions must be specific, well defined, quantifiable, and impact the same general area as the stationary source or modification which causes the secondary emissions. Secondary emissions include emissions from any offsite support facility which would not be constructed or increase its emissions except as a result of the construction or operation of the major stationary source or major modification. Secondary emissions do not include any emissions which come directly from mobile source, such as emissions from the tailpipe of a motor vehicle, from a train, or from a vessel. a 9. Fugitive emissions means those emissions which could not reasonably pass through a stack, chimney, vent, or other functionally equivalent opening. 10. (1) Significant means, in reference to a net emissions increase or the potential of a source to emit any of the following pollutants, a rate of emissions that would equal or exceed any of the following rates: Pollutant and Emissions Rate Carbon monoxide: 100 tons per year (tpy) Nitrogen oxides: 40 tpy Sulfur dioxide: 40 tpy Particulate matter: 25 tpy of particulate matter emissions Ozone: 40 tpy of volatile organic compounds Lead: 0.6 tpy 11. Allowable emissions means the emissions rate calculated using the maximum rated capacity of the source (unless the source is subject to federally enforceable limits which restrict the operating rate, or hours of operation, or both) and the most stringent of the following: (i) Applicable standards as set forth in 40 CFR parts 60 and 61; (ii) Any applicable State Implementation Plan emissions limitation, including those with a future compliance date; or (iii) The emissions rate specified as a federally enforceable permit condition, including those with a future compliance date. 12. Federally enforceable means all limitations and conditions which are enforceable by the Administrator, including those requirements developed pursuant to 40 CFR parts 60 and 61, requirements within any applicable State implementation plan, any permit requirements established pursuant to 40 CFR 52.21 or under regulations approved pursuant to 40 CFR part 51, subpart I, including operating permits issued under an EPA-approved program that is incorporated into the State implementation plan and expressly requires adherence to any permit issued under such program. 13. (i) Actual emissions means the actual rate of emissions of a pollutant from an emissions unit as determined in accordance with paragraphs 16. (ii) through (iv) of Section II.A. of this appendix. (ii) In general, actual emissións as of a particular date shall equal the average rate, in tons per year, at which the unit actually emitted the pollutant during a two-year period which precedes the particular date and which is representative of normal source operation. The reviewing authority shall allow the use of a different time period upon a determination that it is more representative of normal source operation. Actual emissions shall be calculated using the unit's actual operating hours, production rates, and types of materials processed, stored or combusted during the selected time period. (iii) The reviewing authority may presume that source-specific allowable emissions for the unit are equivalent to the actual emissions of the unit. (iv) For any emissions unit which has not begun normal operations on the particular date, actual emissions shall equal the potential to emit of the unit on that date. 14. Construction means any physical change or change in the method of operation (including fabrication, erection, installation, demolition, or modification of an emissions unit) which would result in a change in actual emissions. 15. Commence as applied to construction of a major stationary source or major modi fication means that the owner or operator has all necessary preconstruction approvals or permits and either has: (i) Begun, or caused to begin, a continuous program of actual on-site construction of the source, to be completed within a reasonable time; or (ii) Entered into binding agreements or contractual obligations, which cannot be cancelled or modified without substantial loss to the owner or operator, to undertake a program of actual construction of the source to be completed within a reasonable time. 16. Necessary preconstruction approvals or permits means those permits or approvals required under federal air quality control laws and regulations and those air quality control laws and regulations which are part of the applicable State Implementation Plan. 17. Begin actual construction means, in general, initiation of physical on-site construction activities on an emissions unit which are of a permanent nature. Such activities include, but are not limited to, installation of building supports and foundations, laying of underground pipework, and construction of permanent storage structures. With respect to a change in method of operating this term refers to those on-site activities other than preparatory activities which mark the initiation of the change. 18. Lowest achievable emission rate means, for any source, the more stringent rate of emissions based on the following: (i) The most stringent emissions limitation which is contained in the implementation plan of any State for such class or category of stationary source, unless the owner or operator of the proposed stationary source demonstrates that such limitations are not achievable; or (ii) The most stringent emissions limitation which is achieved in practice by such class or category of stationary source. This limitation, when applied to a modification, means the lowest achievable emissions rate for the new or modified emissions units within the stationary source. In no event shall the application of this term permit a proposed new or modified stationary source to emit any pollutant in excess of the amount allowable under applicable new source standards of performance. 19. Resource recovery facility means any facility at which solid waste is processed for the purpose of extracting, converting to energy, or otherwise separating and preparing solid waste for reuse. Energy conversion facilities must utilize solid waste to provide more than 50 percent of the heat input to be considered a resource recovery facility under this Ruling. 20. Volatile organic compounds excludes: methane; ethane; methylene chloride; 1,1,1 tricholoroethane (methyl chloroform); trichlorotrifluoroethane (CFC-113) (Freon 113); trichlorofluoromethane (CFC-11); dichlorodifluoromethane (CFC-12); chlorodifluoromethane (CFC-22); trifluoromethane (FC-23); dichlorotetrafluoroethane (CFC114); and chloropentafluoroethane (CFC115); dichlorotrifluoroethane (HCFC-123); tetrafluoroethane (HCFC-134a); dichlorofluoroethane (HCFC-141b); and chlorodifluoroethane (HCFC-142b). B. Review of all sources for emission limitation compliance. The reviewing authority must examine each proposed major new source and proposed major modification 1 to determine if such a source will meet all applicable emission requirements in the SIP, any applicable new source performance standard in 40 CFR part 60, or any national emission standard for hazardous air pollutants in 40 CFR part 61. If the reviewing authority determines that the proposed major new source cannot meet the applicable emission requirements, the permit to construct must be denied. C. Review of specified sources for air quality impact. In addition, the reviewing authority must determine whether the major stationary source or major modification would be constructed in an area designated in 40 CFR 81.300 et seq. as nonattainment for a pollutant for which the stationary source or modification is major. (15) Carbon black plants (furnace process); (16) Primary lead smelters; (17) Fuel conversion plants; (18) Sintering plants; (19) Secondary metal production plants; (20) Chemical process plants; (21) Fossil-fuel boilers (or combination thereof) totaling more than 250 million British thermal units per hour heat input; (22) Petroleum storage and transfer units with a total storage capacity exceeding 300,000 barrels; (23) Taconite ore processing plants; (26) Fossil fuel-fired steam electric plants of more than 250 million British thermal units per hour heat input; (27) Any other stationary source category which, as of August 7, 1980, is being regulated under section 111 or 112 of the Act. G. Secondary emissions. Secondary emissions need not be considered in determining whether the emission rates in Section II.C. above would be exceeded. However, if a source is subject to this Ruling on the basis of the direct emissions from the source, the applicable conditions of this Ruling must also be met for secondary emissions. However, secondary emissions may be exempt from Conditions 1 and 2 of Section IV. Also, since EPA's authority to perform or require indirect source review relating to mobile sources regulated under Title II of the Act (motor vehicles and aircraft) has been restricted by statute, consideration of the indirect impacts of motor vehicles and aircraft traffic is not required under this Ruling. III. SOURCES LOCATING IN DESIGNATED CLEAN OR UNCLASSIFIABLE AREAS WHICH WOULD CAUSE OR CONTRIBUTE TO A VIOLATION OF A NATIONAL AMBIENT AIR QUALITY STANDARD A. This section applies only to major sources or major modifications which would locate in an area designated in 40 CFR 81.300 et seq. as attainment or unclassifiable in a state where EPA has not yet approved the state preconstruction review program required by 40 CFR 51.165(b), if the source or modification would exceed the following significance levels at any locality that does not meet the NAAQS: B. Sources to which this section applies must meet Conditions 1, 2, and 4 of Section IV.A. of this ruling. However, such sources may be exempt from Condition 3 of Section IV.A. of this ruling. C. Review of specified sources for air quality impact. For stable air pollutants (i.e. SO2, particulate matter and CO), the determination of whether a source will cause or contribute to a violation of an NAAQS generally should be made on a case-by-case basis as of the proposed new source's startup date using the source's allowable emissions in an atmospheric simulation model (unless a source will clearly impact on a receptor which exceeds an NAAQS). For sources of nitrogen oxides, the initial determination of whether a source would cause or contribute to a violation of the NAAQS for NO, should be made using an atmospheric simulation model assuming all the nitric oxide emitted is oxidized to NO, by the time the plume reaches ground level. 2 The discussion in this paragraph is a proposal, but represents EPA's interim policy until final rulemaking is completed. 0.5 mg/m3. the initial concentration estimates may be adjusted if adequate data are available to account for the expected oxidation rate. For ozone, sources of volatile organic compounds, locating outside a designated ozone nonattainment area, will be presumed to have no significant impact on the designated nonattainment area. If ambient monitoring indicates that the area of source location is in fact nonattainment, then the source may be permitted under the provisions of any state plan adopted pursuant to section 110(a)(2)(D) of the Act until the area is designated nonattainment and a State Implementation Plan revision is approved. If no state plan pursuant to section 110(a)(2)(D) has been adopted and approved, then this Ruling shall apply. As noted above, the determination as to whether a source would cause or contribute to a violation of an NAAQS should be made as of the new source's start-up date. Therefore, if a designated nonattainment area is projected to be an attainment area as part of an approved SIP control strategy by the new source start-up date, offsets would not be required if the new source would not cause a new violation. D. Sources locating in clean areas, but would cause a new violating of an NAAQS. If the reviewing authority finds that the emissions from a proposed source would cause a new violation of an NAAQS, but would not contribute to an existing violation, approval may be granted only if both of the following conditions are met: Condition 1. The new source is required to meet a more stringent emission limitation3 and/or the control of existing sources below allowable levels is required so that the source will not cause a violation of any NAAQS. Condition 2. The new emission limitations for the new source as well as any existing sources affected must be enforceable in accordance with the mechanisms set forth in Section V of this appendix. IV. SOURCES THAT WOULD LOCATE IN A A. Conditions for approval. If the reviewing authority finds that the major stationary source or major modification would be constructed in an area designated in 40 CFR 81.300 et seq as nonattainment for a pollutant for which the stationary source or modification is major, approval may be granted only if the following conditions are met: Condition 1. The new source is required to meet an emission Limitation which speci 3 If the reviewing authority determines that technological or economic limitations on the application of measurement methodology to a particular class of sources would make the imposition of an enforceable numerical emission standard infeasible, the authority may instead prescribe a design, operational or equipment standard. In such cases, the reviewing authority shall make its best estimate as to the emission rate that will be achieved and must specify that rate in the required submission to EPA (see Part V). Any permits issued without an enforceable numerical emission standard must contain enforceable conditions which assure that the design characteristics or equipment will be properly maintained (or that the operational conditions will be properly performed) so as to continuously achieve the assumed degree of control. Such conditions shall be enforceable as emission limitations by private parties under section 304. Hereafter, the term emission limitation shall also include such design, operational, or equipment standards. If the reviewing authority determines that technological or economic limitations on the application of measurement methodology to a particular class of sources would make the imposition of an enforceable numerical emission standard infeasible, the au fies the lowest achievable emission rate for such source." Condition 2. The applicant must certify that all existing major sources owned or operated by the applicant (or any entity controlling, controlled by, or under common control with the appplicant) in the same State as the proposed source are in compliance with all applicable emission limitations and standards under the Act (or are in compliance with an expeditious schedule which is Federally enforceable or contained in a court decree). Condition 3. Emission reductions (offsets) from existing sources in the area of the proposed source (whether or not under the same ownership) are required such that there will be reasonable progress toward attainment of the applicable NAAQS." Only intrapollutant emission offsets will be acceptable (e.g., hydrocarbon increases may not be offset against SO, reductions). Condition 4. The emission offsets will provide a positive net air quality benefit in the affected area (see Section IV.D. below). At thority may instead prescribe a design, operational or equipment standard. In such cases, the reviewing authority shall make its best estimate as to the emission rate that will be achieved and must specify that rate in the required submission to EPA (see Part V). Any permits issued without an enforceable numerical emission standard must contain enforceable conditions which assure that the design characteristics or equipment will be properly maintained (or that the operational conditions will be properly performed) so as to continuously achieve the assumed degree of control. Such conditions shall be enforceable as emission limitations by private parties under section 304. Hereafter, the term emission limitation shall also include such design, operational, or equipment standards. 5 Required only for those pollutants for which the increased allowable emissions exceed 50 tons per year, 1000 pounds per day, or 100 pounds per hour, although the reviewing authority may address other pollutants if deemed appropriate. The preceding hourly and daily rates shall apply only with respect to a pollutant for which a national ambient air quality standard, for a period less than 24 hours or for a 24-hour period, as appropriate, has been established. • Subject to the provisions of section IV.C. below. 7 The discussion in this paragraph is a proposal, but represents EPA's interim policy until final rulemaking is completed. Required only for those pollutants for which the increased allowable emissions exceed 50 tons per year, 1000 pounds per Continued mospheric simulation modeling is not necessary for volatile organic compounds and NO,. Fulfillment of Condition 3 and Section IV.D. will be considered adequate to meet this condition. B. Exemptions from certain conditions. The reviewing authority may exempt the following sources from Condition 1 under Section III or Conditions 3 and 4. Section IV.A.: (i) Resource recovery facilities burning municipal solid waste, and (ii) sources which must switch fuels due to lack of adequate fuel supplies or where a source is required to be modified as a result of EPA regulations (e.g., lead-in-fuel requirements) and no exemption from such regulation is available to the source. Such an exemption may be granted only if: 1. The applicant demonstrates that it made its best efforts to obtain sufficient emission offsets to comply with Condition 1 under Section III or Conditions 3 and 4 under Section IV.A. and that such efforts were unsuccessful; 2. The applicant has secured all available emission offsets; and 3. The applicant will continue to seek the necessary emission offsets and apply them when they become available. Such an exemption may result in the need to revise the SIP to provide additional control of existing sources. Temporary emission sources, such as pilot plants, portable facilities which will be relocated outside of the nonattainment area after a short period of time, and emissions resulting from the construction phase of a new source, are exempt from Conditions 3 and 4 of this section. C. Baseline for determining credit for emission and air quality offsets. The baseline for determining credit for emission and air quality offsets will be the SIP emission limitations in effect at the time the application to construct or modify a source is filed. Thus, credit for emission offset purposes may be allowable for existing control that goes beyond that required by the SIP. Emission offsets generally should be made on a pounds per hour basis when all facilities involved in the emission offset calculations are operating at their maximum expected or allowed production rate. The reviewing agency should specify other averaging periods (e.g., tons per year) in addition to the pounds per hour basis if necessary to carry day, or 100 pounds per hour, although the reviewing authority may address other pollutants if deemed appropriate. The preceding hourly and daily rates shall apply only with respect to a pollutant for which a national ambient air quality standard, for a period less than 24 hours or for a 24-hour period, as appropriate, has been established. out the intent of this Ruling. When offsets are calculated on a tons per year basis, the baseline emissions for existing sources providing the offsets should be calculated using the actual annual operating hours for the previous one or two year period (or other appropriate period if warranted by cyclical business conditions). Where the SIP requires certain hardware controls in lieu of an emission limitation (e.g., floating roof tanks for petroleum storage), baseline allowable emissions should be based on actual operating conditions for the previous one or two year period (i.e., actual throughput and vapor pressures) in conjunction with the required hardware controls. 1. No meaningful or applicable SIP requirement. Where the applicable SIP does not contain an emission limitation for a source or source category, the emission offset baseline involving such sources shall be the actual emissions determined in accordance with the discussion above regarding operating conditions. Where the SIP emission limit allows greater emissions than the uncontrolled emission rate of the source (as when a State has a single particulate emission limit for all fuels), emission offset credit will be allowed only for control below the uncontrolled emission rate. 2. Combustion of fuels. Generally, the emissions for determining emission offset credit involving an existing fuel combustion source will be the allowable emissions under the SIP for the type of fuel being burned at the time the new source application is filed (i.e., if the existing source has switched to a different type of fuel at some earlier date, any resulting emission reduction [either actual or allowable] shall not be used for emission offset credit). If the existing source commits to switch to a cleaner fuel at some future date, emission offset credit based on the allowable emissions for the fuels involved is not acceptable unless the permit is conditioned to require the use of a specified alternative control measure which would achieve the same degree of emission reduction should the source switch back to a dirtier fuel at some later date. The reviewing authority should ensure that adequate long-term supplies of the new fuel are available before granting emission offset credit for fuel switches. 3. (i) Operating hours and source shutdown. A source may generally be credited with emissions reductions achieved by shutting down an existing source or permanently curtailing production or operating hours below baseline levels (see initial discussion in this Section IV.C), if such reductions are permanent, quantifiable, and federally enforceable, and if the area has an EPA-approved attainment plan. In addition, the |