Chapter NR 407

NR 407.03(1s)(a) (a) Eligibility. A facility that is a natural minor source is exempt from the requirement to obtain an operation permit.

NR 407.03(1s)(b) (b) Recordkeeping.

NR 407.03(1s)(b)1. 1. An owner or operator claiming to be exempt under this subsection shall maintain records adequate to show it meets all criteria under the definition of a natural minor source. Emission calculations adequate to determine eligibility with this exemption shall be maintained and made available to a department representative if requested.

NR 407.03(1s)(b)2. 2. In addition to monitoring and recordkeeping requirements contained in any construction permit issued to the source under ch. NR 406, the owner or operator shall maintain records sufficient to demonstrate compliance with all other applicable requirements in chs. NR 400 to 499.

NR 407.03(1s)(c) (c) Notification to the department.

NR 407.03(1s)(c)1. 1. An owner or operator claiming exemption under this subsection and who has an existing permit or who has submitted a permit application under this chapter or under ch. NR 406, shall notify the department of an intent to operate under this exemption.

NR 407.03(1s)(c)2. 2. Any existing permit issued under this chapter shall remain in effect until the permit is revoked or coverage under a general or registration permit is withdrawn at the request of the owner or operator.

NR 407.03(1s)(c)3. 3. A notification under subd. 1. shall serve as a request for revocation of any permits issued under this chapter and for withdrawal of any pending operation permit application submitted under this chapter.

NR 407.03(1s)(d) (d) Schedule. The owner or operator shall apply for an operation permit in accordance with the requirements of this chapter if any of the following affects the source’s ability to remain a natural minor source:

NR 407.03(1s)(d)1. 1. Any existing requirements change.

NR 407.03(1s)(d)2. 2. Any new requirements become applicable to the source.

NR 407.03(1s)(d)3. 3. Changes occur at the source.

NR 407.03(1s)(d)4. 4. Other emission information indicating that the source is not a natural minor source becomes available.

NR 407.03 Note Note: An owner or operator exempt under this subsection is responsible for complying with all applicable requirements in chs. NR 400 to 499, including construction permit requirements identified in ch. NR 406 and all conditions contained in a permit issued under ch. NR 406.

NR 407.03 Note Note: The exemption in this subsection does not preclude the owner or operator of a natural minor source from requesting, and the Department from issuing, an operation permit as allowed under s. 285.60 (2) (b), Stats.

NR 407.03 Note Note: The Small Business Environmental Assistance Program at dnr.wi.gov may be contacted for more information on applicability and compliance determinations related to the requirements in chs. NR 400 to 499.

NR 407.03(2) (2) General category of exempt sources. In addition to the specific categories of exempt sources identified in sub. (1), no operation permit is required for a direct source if the source is not a part 70 source or an affected source and all of the following requirements are met:

NR 407.03(2)(a) (a) The maximum theoretical emissions from the source for sulfur dioxide or carbon monoxide do not exceed 9.0 pounds per hour for each air contaminant.

NR 407.03(2)(b) (b) The maximum theoretical emissions from the source for particulate matter, nitrogen oxides or volatile organic compounds do not exceed 5.7 pounds per hour for each air contaminant.

NR 407.03(2)(ba) (ba) The maximum theoretical emissions from the source for PM10 do not exceed 3.4 pounds per hour.

NR 407.03(2)(be) (be) The maximum theoretical emissions from the source for PM2.5 do not exceed 2.2 pounds per hour.

NR 407.03(2)(bm) (bm) The maximum theoretical emissions from the source for lead do not exceed 0.13 pounds per hour.

NR 407.03(2)(c) (c) The source will not emit any of the air contaminants listed in s. NR 405.02 (27) (a) at a rate greater than the applicable emission rate listed in s. NR 405.02 (27) (a).

NR 407.03(2)(d) (d) The maximum theoretical emissions from the source for any hazardous air contaminant listed in Table A, B or C of s. NR 445.07 do not exceed the emission rate listed in the table for the hazardous air contaminant for the respective stack height. For the purposes of determining emissions under this paragraph, the owner or operator of a source is not required to consider emissions of hazardous air contaminants associated with agricultural waste.

NR 407.03 Note Note: Par. (d) is shown as affected by 2011 Wis. Act 122. On May 24, 2011, the Joint Committee for the Review of Administrative Rules (JCRAR) adopted a motion under s. 227.26 (2) (d), Stats., that suspended s. NR 407.03 (2) (d) in part as shown below. Pursuant to s. 227.26 (2) (f), Stats., JCRAR introduced 2011 Assembly Bill 195 and 2011 Senate Bill 138, in support of the JCRAR suspension. 2011 Senate Bill 138 was enacted, effective March 22, 2012, resulting in the repeal of the rules as suspended by the May 24, 2011 JCRAR motion, as provided in s. 227.26 (2) (i), Stats., and creating s. 285.28, Stats., as set forth below.

NR 407.03 Note NR 407.03 (2) (d) The maximum theoretical emissions from the source for any hazardous air contaminant listed in Table A, B or C of s. NR 445.07 do not exceed the emission rate listed in the table for the hazardous air contaminant for the respective stack height. For the purposes of determining emissions under this paragraph, the owner or operator of a source is not required to consider emissions of hazardous air contaminants associated with agricultural waste prior to July 31, 2011.

NR 407.03 Note 285.28 Agricultural waste; hazardous air contaminants. The department may not regulate the emission of hazardous air contaminants associated with agricultural waste except to the extent required by federal law.

NR 407.03 Note Note: Owners and operators of facilities emitting less than 3 tons of volatile organic compounds and 5 tons of particulate matter on an annual basis, or who engage in limited or no manufacturing activities, should refer to s. NR 445.11 prior to determining applicable requirements under this section.

NR 407.03(2)(e) (e) The source will not have maximum theoretical emissions of any single hazardous air pollutant listed under section 112 (b) of the Act (42 USC 7412 (b)) that equal or exceed 10 tons per year or cumulative maximum theoretical emissions of all the hazardous air pollutants listed under section 112 (b) of the Act (42 USC 7412 (b)) that equal or exceed 25 tons per year.

NR 407.03(2)(f) (f) The source is not subject to an emission limitation or emission standard under section 111 of the Act (42 USC 7411) excluding engines certified to meet the emission standards in 40 CFR part 60, subpart IIII or JJJJ for each fuel used.

NR 407.03(2)(g) (g) The source is not subject to an emission limitation or emission standard under section 112 of the Act (42 USC 7412), excluding section 112 (d) (5) or (r) (42 USC 7412 (d) (5) or (r)).

NR 407.03(3) (3) Exempt equipment. Equipment installed under s. NR 406.04 (1) (i) or (zg) is exempt from needing an operation permit under this chapter. 

NR 407.03(4) (4) Conditions for specific exemptions. In order to be eligible for a specific exemption under sub. (1) (ce), (cm), (d), (g), (gm), (h), (o), (s), (w) or (x), the owner or operator of a direct stationary source shall keep and maintain the records required under pars. (a) to (f), as applicable. The records shall be kept in a manner that allows the source to accurately calculate the required information on a monthly basis. The owner or operator of a direct stationary source shall begin keeping the records required under pars. (b) to (f) no later than January 1, 1994, and the records required under par. (a) no later than January 1, 1998, or the date that the source commences operation, whichever is later, and maintain them for a minimum of 5 years. After January 1, 1994, any direct stationary source that ever exceeds any level listed in sub. (1) (d), (g), (h), (o), (s), (sm), (w) or (x) is not eligible for the exemption under that subsection. After January 1, 1998, any direct stationary source that ever exceeds any level listed in sub. (1) (ce) or (cm) is not eligible for the exemption under that subsection. After February 1, 2001, any direct stationary source that ever exceeds any level listed in sub. (1) (gm) is not eligible for the exemption under that subsection. The records required are as follows:

NR 407.03(4)(a) (a) To be exempt under sub. (1) (ce) or (cm), records of the tons of grain received at the grain storage or processing facility per month.

NR 407.03(4)(b) (b) To be exempt under sub. (1) (d), records of the cubic yards of concrete produced by the Portland concrete batch plant per month.

NR 407.03(4)(c) (c) To be exempt under sub. (1) (g), (gm) or (h), records of the amounts used and VOC content of all VOC containing materials used at the facility per month.

NR 407.03(4)(d) (d) To be exempt under sub. (1) (o), records of the number of hours that the laboratory operates, the amounts, VOC content and hazardous air contaminant content of all materials used and the amount, type and sulfur content of all fuels used per month.

NR 407.03(4)(e) (e) To be exempt under sub. (1) (s), records of the daily gasoline throughput for the bulk plant.

NR 407.03(4)(f) (f) To be exempt under sub. (1) (w) or (x), records of the tons of material produced at a ledge rock quarry or sand mine per month, or for ledge rock quarries exempt for operating less than 365 days in a 5-year period, records indicating each day that the quarry operates.

NR 407.03 Note Note: Between January 1, 1994 and January 1, 1998, s. NR 407.03 (4) contained recordkeeping requirements which were less specific than those set forth in pars. (b) to (f). Compliance with the recordkeeping requirements in this subsection will be assessed based on the administrative rule in effect at the time.

NR 407.03 History History: Cr. Register, December, 1984, No. 348, eff. 1-1-85; cr. (2) (bm), r. and recr. (2) (d), am. (2) (e), Register, September, 1988, No. 393; eff. 10-1-88; am. (1) (a) (intro.), 1. to 3., (b), (g), (h), (o), (2) (a), (b), (bm), (c) 1. and 5., (d) and (e), Register, May, 1992, No. 437, eff. 6-1-92; am. (1) (intro.), (a) (intro.) and 5., (b) to (e), (2) (intro.), (a) to (c), cr. (1) (sm), (sq) and (u), (2) (f), (g), (3) to (5), r. (2) (c) 1. to 5., r. and recr. (2) (e), Register, December, 1993, No. 456, eff. 1-1-94; cr. (1) (v) to (z), Register, June, 1994, No. 462, eff. 7-1-94; am. (1) (sm) (intro.), 1. to 3., r. 5., renum. 6. to 10. to be 5. to 9. and am. 7. and 9., Register, September, 1994, No. 465, eff. 10-1-94; am. (2) (d), Register, December, 1994, No. 468, eff. 1-1-95; am. (1) (intro.), (2) (intro.), Register, April, 1995, No. 472, eff. 5-1-95; am. (1) (a) 5., r. and recr. (1) (k), r. (3) and (5), Register, June, 1995, No. 474, eff. 7-1-95; am. (1) (sm) (intro.), Register, August, 1995, No. 476, eff. 9-1-95; am. (1) (g), (h), (o), (2) (b) and (4), Register, December, 1995, No. 480, eff. 1-1-96; am. (1) (g), (sm) 9., Register, December, 1996, No. 492, eff. 1-1-97; am. (1) (i) and (j), Register, March, 1997, No. 495, eff. 4-1-97; cr. (1) (km), Register, September, 1997, No. 501, eff. 10-1-97; cr. (1) (ce), (cm), (t) 4., 5., (3), (4) (a) to (f); am. (1) (s), (sm) (intro.), (t) (intro.), 1. and (4), renum. (1) (t) 4. to be (1) (t) 6. and am., Register, December, 1997, No. 504, eff. 1-1-98; am. (1) (g), (h), (o), (2) (intro.), (e) and (g), Register, October, 1999, No. 526, eff. 11-1-99; cr. (1) (gm), am. (4) (intro.) and (c), Register, January, 2001, No. 541, eff. 2-1-01; CR 02-097: am (1) (sm) (intro.) and (2) (d) Register June 2004 No. 582, eff. 7-1-04; CR 04-107: r. (1) (c), am. (1) (ce) and (cm) Register August 2005 No. 596, eff. 9-1-05; correction in (1) (t) 6. made under s. 13.93 (2m) (b) 7., Stats., Register August 2005 No. 596; CR 06-047: cr. (1m) Register May 2007 No. 617, eff. 6-1-07; corrections in (1) (a) and (b) made under s. 13.93 (2m) (b) 7., Stats., Register May 2007 No. 617; CR 07-076: am. (2) (d) Register July 2008 No. 631, eff. 8-1-08; CR 09-020: am. (1) (g), (gm), (h), (o), (sm) (intro.), (sq), (1m) (a) 2., (2) (e), (f), (g), and (4) (intro.) Register January 2010 No. 649, eff. 2-1-10; CR 10-050: cr. (2) (be) Register November 2010 No. 659, eff. 12-1-10; 2011 Wis. Act 122: r. in part (2) (d) eff. 3-22-12; s. 35.17, Stats., correction in (1m) (a) 2., Register February 2014 No. 698; CR 15-005: renum. (1) (u) to (1) (u) (intro.) and am., cr. (1) (u) 1., 2., (1s) Register November 2015 No. 719, eff. 12-1-15; CR 19-015: am. (1) (intro.), cr. (1) (a) 4m., (bm), am. (1m) (a) 2., (c) 1., cr. (2) (ba), am. (2) (f), (g) Register September 2020 No. 777, eff. 10-1-20.

NR 407.04 NR 407.04 Permit application requirements. The owner or operator of an air contaminant source which is not exempt under s. 285.60 (5), Stats., or s. NR 407.03 shall submit an operation permit application or renewal application, in accordance with s. NR 407.05, by the dates specified in this section:

NR 407.04(1) (1) Initial filing dates. Except as provided under subs. (3) to (7), the initial operation permit application shall be submitted by one of the following dates:

NR 407.04 Note Note: Application forms may be obtained from the Department Regional Headquarter or Service Center offices or from the Wisconsin Department of Natural Resources, Bureau of Air Management, PO Box 7921, Madison WI 53707-7921, Attention: operation permits.

NR 407.04(1)(a) (a) Existing sources, initial application. For initial applications for all existing sources, the date in the appropriate column of Table 1 for part 70 and non-part 70 sources corresponding to the county in which the source is located. Where the location of a source is in 2 or more counties, the date an application is due shall be the latest date listed for any of the counties in which the source is located. Any existing air contaminant source for which an application is submitted requesting that it be made a synthetic minor source is a part 70 source until a permit making that source a synthetic minor source is issued and, except as allowed in sub. (3), is subject to the filing dates listed for part 70 sources. If a source submits an application on or before the date specified in Table 1 and the department determines that the application is incomplete, the source shall have 30 days from the date that the department notifies the source of the incompleteness determination to complete the application.

NR 407.04(1)(b) (b) New and modified sources.

NR 407.04(1)(b)1. 1. In accordance with s. 285.62 (11) (b) 2., Stats., for new or modified sources for which a construction permit is required and which apply for a construction permit after November 15, 1992, the date that the application for the construction permit is filed.

NR 407.04(1)(b)2. 2. For new or modified sources for which a construction permit is required and which applied for a construction permit before November 15, 1992, a date at least 120 days prior to the expiration date of the construction permit.

NR 407.04(1)(b)3. 3. For new or modified sources for which no construction permit is required, a date before the source commences construction or modification. For purposes of determining the date of commencement of construction or modification, the exclusions provided in s. NR 406.03 (1e) shall apply.

NR 407.04(2) (2) Permit renewal. Pursuant to s. 285.66 (3), Stats., a permittee shall apply for renewal of an operation permit at least 6 months before the permit expires. No permittee may continue operation of a source after the operation permit expires, unless the permittee submits a timely and complete application for renewal of the permit.

NR 407.04 Note Note: Under 40 CFR 70.5(a)(1)(iii), the renewal application must be submitted at least 6 months, but not more than 18 months before the permit expires.

NR 407.04(3) (3) Extensions and deferrals.

NR 407.04(3)(a) (a) Extensions for cause. An existing source may request and the department may grant an extension of not more than 60 days beyond the applicable date specified in sub. (1) (a) if all of the following conditions are met:

NR 407.04(3)(a)1. 1.

NR 407.04(3)(a)1.a. a. The extension is requested in writing at least 30 but no more than 90 days before the application is due.

NR 407.04(3)(a)1.b. b. The department may waive the 30 day requirement in subd. 1. a. if an emergency occurs that makes it impossible for the source to meet that deadline.

NR 407.04(3)(a)2. 2. The applicant demonstrates that the reason that they cannot meet the date specified in sub. (1) (a) is beyond their reasonable control.

NR 407.04(3)(a)3. 3. The extension does not extend the date that a complete application is due for a part 70 source beyond November 15, 1995.

NR 407.04(3)(b) (b) Deferral for sources proposing to become synthetic minor sources.

NR 407.04(3)(b)1. 1. If an existing source proposes to be permitted as a synthetic minor source in order to avoid being classified as a part 70 source, the owner or operator shall:

NR 407.04(3)(b)1.a. a. Submit a complete application for an operation permit for a non- part 70 source in accordance with s. NR 407.05 (4) and (8) by the date that a part 70 source permit application would be due for that source under the schedule in Table 1.

NR 407.04(3)(b)1.b. b. Submit information to show that the actual emissions of each air contaminant emitted by the source for the 2 most recent years prior to the submittal of the application for an operation permit were less than the corresponding thresholds for being classified a major source under s. NR 407.02 (4). If available, actual emissions, as reported to the department pursuant to ch. NR 438, shall be submitted.

NR 407.04(3)(b)1.c. c. Submit information to show that the source is a part 70 source solely due to its classification as a major source.

NR 407.04(3)(b)2. 2. The department shall review the application and determine whether the source may be permitted as a non-part 70 source and whether the source has demonstrated that the requirements of subd. 1. have been met. If the department determines that the source may be permitted as a non-part 70 source and the requirements of subd. 1. have been met, it shall process the application in accordance with s. 285.62, Stats., and ss. NR 407.07 and 407.09. If the department determines that the source may not be permitted as a non-part 70 source, the department shall notify the source of that determination. The owner or operator of the source shall then submit to the department a complete application for a part 70 source in accordance with s. NR 407.05 (4) by October 30, 1995.

NR 407.04(4) (4) Perchloroethylene dry cleaning facilities. Notwithstanding sub. (1), the owner or operator of any perchloroethylene dry cleaning facility that is not a major source or located at a major source as defined in s. NR 468.20 (2) (L), is not required to obtain a construction permit under ch. NR 406 and on which construction commenced prior to July 1, 1995, shall submit an operation permit application, on application forms available from the department, by July 1, 1996.

NR 407.04(5) (5) Halogenated solvent cleaning. Notwithstanding sub. (1) and except as provided in sub. (4), the owner or operator of any batch vapor or in-line cleaning machine as defined in s. NR 469.02 (3), (26) and (44) that uses any halogenated HAP solvent as a cleaning or drying agent and that is not a major source or located at a major source and on which construction commenced prior to April 1, 1997, shall submit an operation permit application for a part 70 source, on application forms available from the department, by the date that an operation permit application for a non-part 70 source would be due for that source under the schedule in Table 1.

NR 407.04(6) (6) Chromium electroplating and chromium anodizing operations. Notwithstanding sub. (1), the owner or operator of any facility which does hard or decorative chromium electroplating as defined in s. NR 463.02 (18) and (10) or chromium anodizing as defined in s. NR 463.02 (7) that is not a major source or located at a major source, is not required to obtain a construction permit under ch. NR 406, and on which construction commenced prior to October 1, 1997, shall submit an operation permit application for a part 70 source, on application forms available from the department, by the date that an operation permit application for a non-part 70 source would be due for that source under the schedule in Table 1.

NR 407.04(7) (7) Secondary aluminum processing units. Notwithstanding sub. (1), the owner or operator of any facility which has a secondary aluminum processing unit as defined in s. NR 463.12 (35) that is not a major source and is not required to obtain a construction permit under ch. NR 406, shall submit an operation permit application for a non-part 70 source on application forms available from the department no later than one year after January 1, 2009.

NR 407.04 History History: Cr. Register, December, 1984, No. 348, eff. 1-1-85; renum. (1) to be (1) (a), cr. (1) (b), Register, September, 1988, No. 393, eff. 10-1-88; am. (1) (a), renum. Table, Register, May, 1992, No. 437, eff. 6-1-92; am. (1) (a), Register, June, 1993, No. 450, eff. 7-1-93; r. and recr. Register, December, 1993, No. 456, eff. 1-1-94; am. (1) (intro.), cr. (4), Register, June, 1995, No. 474, eff. 7-1-95; am. (3) (b) 1. b., Register, December, 1996, No. 492, eff. 1-1-97; am. (1) (intro.) and (4) and cr. (5), Register, March, 1997, No. 495, eff. 4-1-97; am. (1) (intro) and cr. (6), Register, September, 1997, No. 501, eff. 10-1-97; cr. (intro.) and am. (1) (intro.) and (b) 3., Register, October, 1999, No. 526, eff. 11-1-99; CR 04-023: cr. (7) Register December 2008 No. 636, eff. 1-1-09; CR 09-020: am. (2) Register January 2010 No. 649, eff. 2-1-10; CR 15-005: am. (1) (intro.), (b) 3. Register November 2015 No. 719, eff. 12-1-15; correction in (1) (b) 3. made under s. 35.17, Stats., Register November 2015 No. 719.

NR 407.05 NR 407.05 Applications and forms.

NR 407.05(1) (1) Applications for operation permits and renewals of operation permits shall be made on forms supplied by the department for these purposes and supplemented with other materials as indicated on the forms. The forms may be supplied by the department in an electronic format, such as on a computer disk, or on line, if so requested by the applicant.

NR 407.05 Note Note: Application forms may be obtained from the Department Regional Headquarters or Service Center offices or from the Wisconsin Department of Natural Resources, Bureau of Air Management, PO Box 7921, Madison WI 53707-7921, Attention: operation permits. The internet web address is: http://dnr.wi.gov/topic/AirPermits/Forms.html.

NR 407.05(2) (2) Application materials may be submitted on paper or in an electronic format. The applicant shall submit all forms and other required materials, as indicated on the forms. When electing to submit materials on paper, the applicant shall submit the materials to the Wisconsin Department of Natural Resources, Bureau of Air Management, PO Box 7921, Madison WI 53707-7921, Attention: Operation permits.

NR 407.05(3) (3) The application forms shall be signed by a responsible official of the stationary source designated by the source for this purpose. In the case of an electronic format application, a form supplied with the electronic format shall be signed in accordance with this subsection and returned to the department with the electronic format application.

NR 407.05(4) (4) The application shall contain all of the information required for the issuance of an operation permit. Except as provided in subs. (5) and (8), it shall include the following elements:

NR 407.05(4)(a) (a) Identifying information, including company name and address, and plant name and address if different from the company name or address, owner’s name and agent, and operator if different from the owner, and names and telephone numbers of the plant manager and contact person.

NR 407.05(4)(b) (b) A description of the source’s processes and products, by standard industrial classification code as described in the Standard Industrial Classification Manual, 1987, incorporated by reference in s. NR 484.05, including any processes and products associated with each alternate operating scenario identified by the source.

NR 407.05(4)(c) (c) The following emissions-related information:

NR 407.05(4)(c)1. 1. The maximum theoretical emissions of all air contaminants from all emissions units, operations, and activities except for those exempted under subd. 9. or 10. Fugitive emissions from emissions units, operations, and activities shall be included in the permit application in the same manner as stack emissions, regardless of whether the source category in question is included in the list of sources contained in the definition of major source. Maximum theoretical fugitive emissions shall be calculated using average operating conditions and average weather conditions. Only sources that manufacture or treat pesticides, rodenticides, insecticides, herbicides, fungicides, or pharmaceuticals shall include emissions of air contaminants identified as falling within the categories in Table 3 in permit applications. When preparing an application, the owner or operator of a facility may rely on information in an approved material safety data sheet. Trace contaminants need not be reported if they constitute less than 1% (10,000 parts per million) of the material, or 0.1% (1,000 parts per million) of the material if the air contaminant is listed with a control requirement in column (i) of Table A, B or C of s. NR 445.07, unless a hazardous air contaminant is formed in processing the material.

NR 407.05(4)(c)2. 2. Identification and description of all emissions points in sufficient detail to determine the applicable requirements to be included in an operation permit.

NR 407.05(4)(c)3. 3. Emission rates in tons per year and in terms necessary to demonstrate compliance with emission limitations consistent with the applicable reference test method.

NR 407.05(4)(c)4. 4. The following information to the extent that it is needed to determine or regulate emissions: types and amounts of fuels used, types and amounts of raw materials used, production rates and operating schedules.

NR 407.05(4)(c)5. 5. Identification and description of air pollution control equipment and compliance monitoring devices or activities.

NR 407.05(4)(c)6. 6. Limitations on source operations and any applicable work practice standards which affect emissions of any air contaminants.

NR 407.05(4)(c)7. 7. Other information necessary to determine any applicable requirement.

NR 407.05(4)(c)8. 8. The calculations on which the information contained in subds. 1. to 7. is based.

NR 407.05(4)(c)9. 9. The emissions units, operations and activities in subd. 9. a. to o. shall be listed in the application but are exempt from being further included in any application required under this chapter:

NR 407.05(4)(c)9.a. a. Any emissions unit, operation, or activity that has, for each air contaminant, maximum theoretical emissions that are less than the level specified in Table 3. Multiple emissions units, operations, and activities that perform identical or similar functions shall be combined in determining the applicability of the exemption under this subd. 9. a.

NR 407.05(4)(c)9.b. b. If the maximum theoretical emissions of any air contaminants listed in Table 3 from all emission units, operations, or activities at a facility are less than 5 times the level specified in Table 3 for those air contaminants, any emissions unit, operation, or activity that emits only those air contaminants.