Unless specifically defined in the Texas Clean Air Act (TCAA) or in the rules of the commission, the terms used by the commission have the meanings commonly ascribed to them in the field of air pollution control. The terms in this section are applicable to permit review for major source construction and major source modification in nonattainment areas. In addition to the terms which are defined by the TCAA, and in §101.1 of this title (relating to Definitions), the following words and terms, when used in §116.150 and §116.151 of this title (relating to Nonattainment Review), shall have the following meanings, unless the context clearly indicates otherwise.

1. (1) Actual emissions--Actual emissions 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 executive director 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. The executive director may presume that the source-specific allowable emissions for the unit are equivalent to the actual emissions, e.g., when the allowable limit is reflective of actual emissions. For any emissions unit which has not begun normal operations on the particular date, actual emissions shall equal the potential to emit the unit on that date.

2. (2) Allowable emissions--The emissions rate of a stationary source, 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:

   1. (A) the applicable standards set forth in Title 40 Code of Federal Regulations, Part 60 or 61;
   2. (B) the applicable state implementation plan emissions limitation including those with a future compliance date; or
   3. (C) the emissions rate specified as a federally enforceable permit condition including those with a future compliance date.
3. (3) Begin actual construction--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 operation, this term refers to those on-site activities other than preparatory activities which mark the initiation of the change.
4. (4) Building, structure, facility, or installation--All of the pollutant-emitting activities which belong to the same industrial grouping, are located in one or more contiguous or adjacent properties, and are under the control of the same person (or persons under common control) except the activities of any vessel. Pollutant-emitting activities shall be considered as part of the same industrial grouping if they belong to the same "major group" (i.e., which have the same two-digit code) as described in the Standard Industrial Classification Manual, 1972, as amended by the 1977 supplement.

5. (5) Commence--As applied to construction of a major stationary source or major modification, means that the owner or operator has all necessary preconstruction approvals or permits and either has:

   1. (A) begun, or caused to begin, a continuous program of actual on-site construction of the source, to be completed within a reasonable time; or
   2. (B) entered into binding agreements or contractual obligations, which cannot be canceled 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.
6. (6) Construction--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.

7. (7) Contemporaneous period--As follows.

   1. (A) For major sources with the potential to emit 250 tpy or more of a nonattainment pollutant, the period between:

      1. (i) November 15, 1992; and
      2. (ii) the date that the increase from the particular change occurs.

   2. (B) For major sources with the potential to emit less than 250 tpy of a nonattainment pollutant, the period between:

      1. (i) the date five years before construction on the particular change commences; and
      2. (ii) the date that the increase from the particular change occurs.
   3. (C) Notwithstanding subparagraphs (A) and (B) of this definition, for major sources of nitrogen oxides as a precursor to ozone in ozone nonattainment areas, the contemporaneous period shall begin no earlier than November 15, 1992.
8. (8) De minimis threshold test (netting)--A method of determining if a proposed emission increase will trigger nonattainment review. The summation of the proposed increase with all other creditable source emission increases and decreases during the contemporaneous period is compared to the MAJOR MODIFICATION column of Table I (in tpy) for that specific nonattainment area. If the major modification level is exceeded, then nonattainment review is required.

9. (9) Lowest achievable emission rate--For any emitting facility, that rate of emissions of a contaminant which does not exceed the amount allowable under applicable New Source Performance Standards promulgated by the United States Environmental Protection Agency under the Federal Clean Air Act, §111, and which reflects the following:

   1. (A) the most stringent emission limitation which is contained in the rules and regulations of any approved state implementation plan for a specific class or category of facility, unless the owner or operator of the proposed facility demonstrates that such limitations are not achievable; or
   2. (B) the most stringent emission limitation which is achieved in practice by a specific class or category of facilities, whichever is more stringent.
10. (10) Major facility/stationary source--Any facility/stationary source which emits, or has the potential to emit, the amount specified in the MAJOR SOURCE column of Table I of this section or more of any air contaminant (including volatile organic compounds) for which a National Ambient Air Quality Standard (NAAQS) has been issued. Any physical change that would occur at a stationary source not qualifying as a major stationary source in Table I of this section, if the change would constitute a major stationary source by itself. A major stationary source that is major for volatile organic compounds or nitrogen oxides shall be considered major for ozone. The fugitive emissions of a stationary source shall not be included in determining for any of the purposes of this definition whether it is a major stationary source, unless the source belongs to one of the categories of stationary sources listed in Title 40 Code of Federal Regulations, Part 51.165(a)(1)(iv)(C).

11. (11) Major modification--Any physical change in, or change in the method of operation of a facility/stationary source that causes a significant net emissions increase for any air contaminant for which an NAAQS has been issued. At a facility/stationary source that is not major prior to the increase, the increase by itself must equal or exceed that specified in the MAJOR SOURCE column of Table I of this section. At an existing major facility/stationary source, the increase must equal or exceed that specified in the MAJOR MODIFICATION column of Table I. A physical change or change in the method of operation shall not include:

    1. (A) routine maintenance, repair, and replacement;
    2. (B) use of an alternative fuel or raw material by reason of an order under the Energy Supply and Environmental Coordination Act of 1974, §2(a) and (b) (or any superseding legislation), or by reason of a natural gas curtailment plan pursuant to the Federal Power Act;
    3. (C) use of an alternative fuel by reason of an order or rule of the Federal Clean Air Act, §125;
    4. (D) use of an alternative fuel at a steam generating unit to the extent that the fuel is generated from municipal solid waste;
    5. (E) use of an alternative fuel or raw material by a stationary source which the source was capable of accommodating before December 21, 1976 (unless such change would be prohibited under any federally enforceable permit condition established after December 21, 1976) or the source is approved to use under any permit issued under regulations approved pursuant to this chapter;
    6. (F) an increase in the hours of operation or in the production rate (unless the change is prohibited under any federally enforceable permit condition which was established after December 21, 1976); or
    7. (G) any change in ownership at a stationary source.

Source Note:The provisions of this §116.12 adopted to be effective September 13, 1993, 18 TexReg 5746; amended to be effective June 7, 1996, 21 TexReg 4790; amended to be effective April 7, 1998, 23 TexReg 3515.