December 6, 2010

Andrea L. Stomberg

Montana-Dakota Utilities Co.

400 North Fourth Street

Bismark, ND 58501

RE: Final Title V Operating Permit #OP0691-05

Dear Ms. Stromberg:

The Department of Environmental Quality has prepared the enclosed Final Operating Permit #OP0691-

05, for Montana-Dakota Utilities, Inc. Lewis and Clark Station, located in the Southwest 1⁄4 of Section 9, 

Township 22 North, Range 59 East, in Richland County, Montana. Please review the cover page of the 

attached permit for information pertaining to the action taking place on Permit #OP0691-05. 

If you have any questions, please contact Shawn Juers, the permit writer, at (406) 444-2049 or by email at 

sjuers@mt.gov.

Sincerely,

Vickie Walsh

Air Permitting Program Supervisor

Air Resources Management Bureau

(406) 444-9741

 

 Shawn Juers

 Environmental Engineer

 Air Resources Management Bureau

 (406) 444-2049

VW:SJ

Enclosure 

cc: Christopher Ajayi, US EPA Region VIII 8P-AR

Carson Coate, US EPA Region VIII, Montana Office
OP0691-05 i Decision: 11/03/10

Effective Date: 12/04/10

STATE OF MONTANA

Department of Environmental Quality

Helena, Montana 59620

AIR QUALITY OPERATING PERMIT OP0691-05

Issued to: Montana-Dakota Utilities Co.

Lewis and Clark Station

400 North Fourth Street

Bismark, ND 58501

Final Date: December 4, 2010

Expiration Date: August 24, 2014

Effective Date: December 4, 2010

Date of Decision: November 3, 2010

Request Deemed Technically Complete: June 21, 2010 and August 31, 2010

Request Deemed Administratively Complete: June 21, 2010 and August 31, 2010

Administrative Amendment Request Received: May 24, 2010 and August 31, 2010

AFS Number: 030-053-0002A

Permit Issuance and Appeal Processes: In accordance with Montana Code Annotated (MCA) Sections 

75-2-217 and 218 and the Administrative Rules of Montana (ARM), ARM Title 17, Chapter 8, 

Subchapter 12, Operating Permit Program, this operating permit is hereby issued by the Department of 

Environmental Quality (Department) as effective and final on December 4, 2010. This cover sheet must 

be attached to the Date of Decision issued on November 3, 2010, and the permit must be kept on-site at 

the above named facility.
OP0691-05 ii Decision: 11/03/10

Effective Date: 12/04/10

Montana Air Quality Operating Permit

Department of Environmental Quality

SECTION I. GENERAL INFORMATION ........................................................................................1

SECTION II. SUMMARY OF EMISSION UNITS.............................................................................2

SECTION III. PERMIT CONDITIONS............................................................................................3

A. FACILITY-WIDE........................................................................................................................... 3

B. EU01: TANGENTIAL COAL-FIRED BOILER (COAL AND NATURAL GAS) .................................... 6

C. EU06: FUEL (GASOLINE) STORAGE TANK ................................................................................ 10

D. EU07: COAL STORAGE PILES ................................................................................................... 10

E. EU08: FUGITIVE COAL, ASH, AND LIME HANDLING................................................................ 12

SECTION IV. NON-APPLICABLE REQUIREMENTS...............................................................14

A. FACILITY-WIDE......................................................................................................................... 14

B. EMISSION UNITS........................................................................................................................ 15

SECTION V. GENERAL PERMIT CONDITIONS .........................................................................16

A. COMPLIANCE REQUIREMENTS................................................................................................... 16

B. CERTIFICATION REQUIREMENTS ............................................................................................... 16

C. PERMIT SHIELD ......................................................................................................................... 17

D. MONITORING, RECORDKEEPING, AND REPORTING REQUIREMENTS ......................................... 18

E. PROMPT DEVIATION REPORTING............................................................................................... 19

F. EMERGENCY PROVISIONS.......................................................................................................... 19

G. INSPECTION AND ENTRY ........................................................................................................... 20

H. FEE PAYMENT ........................................................................................................................... 20

I. MINOR PERMIT MODIFICATIONS ............................................................................................... 21

J. CHANGES NOT REQUIRING PERMIT REVISION .......................................................................... 21

K. SIGNIFICANT PERMIT MODIFICATIONS...................................................................................... 22

L. REOPENING FOR CAUSE............................................................................................................. 22

M. PERMIT EXPIRATION AND RENEWAL......................................................................................... 23

N. SEVERABILITY CLAUSE ............................................................................................................. 23

O. TRANSFER OR ASSIGNMENT OF OWNERSHIP ............................................................................. 24

P. EMISSIONS TRADING, MARKETABLE PERMITS, ECONOMIC INCENTIVES .................................. 24

Q. NO PROPERTY RIGHTS CONVEYED ........................................................................................... 24

R. TESTING REQUIREMENTS .......................................................................................................... 24

S. SOURCE TESTING PROTOCOL .................................................................................................... 24

T. MALFUNCTIONS ........................................................................................................................ 24

U. CIRCUMVENTION....................................................................................................................... 24

V. MOTOR VEHICLES ..................................................................................................................... 24

W. ANNUAL EMISSIONS INVENTORY .............................................................................................. 25

X. OPEN BURNING ......................................................................................................................... 25

Y. MONTANA AIR QUALITY PERMITS............................................................................................ 25

Z. NATIONAL EMISSION STANDARD FOR ASBESTOS ..................................................................... 26

AA. ASBESTOS.................................................................................................................................. 26

BB. STRATOSPHERIC OZONE PROTECTION – SERVICING OF MOTOR VEHICLE AIR CONDITIONERS 26

CC. STRATOSPHERIC OZONE PROTECTION – RECYCLING AND EMISSION REDUCTIONS .................. 26

DD. EMERGENCY EPISODE PLAN...................................................................................................... 27

EE. DEFINITIONS.............................................................................................................................. 27

APPENDIX A INSIGNIFICANT EMISSION UNITS .................................................................A-1

APPENDIX B DEFINITIONS AND ABBREVIATIONS ............................................................B-1
OP0691-05 iii Decision: 11/03/10

Effective Date: 12/04/10

APPENDIX C NOTIFICATION ADDRESSES............................................................................C-1

APPENDIX D AIR QUALITY INSPECTOR INFORMATION.................................................D-1

APPENDIX E PREDICTIVE OPACITY ......................................................................................E-1

APPENDIX F SO2 CEMS ............................................................................................................... F-1

APPENDIX G NOX CEMS ..............................................................................................................G-1

APPENDIX H ACID RAIN .............................................................................................................H-1

APPENDIX I COMPLIANCE ASSURANCE MONITORING (CAM) PLAN.............................I-1

APPENDIX J MEMS...........................................................................................................................J-1
OP0691-05 1 Decision: 11/03/10

Effective Date: 12/04/10

Terms not otherwise defined in this permit or in the Definitions and Abbreviations Appendix of this 

permit have the meaning assigned to them in the referenced regulations.

SECTION I. GENERAL INFORMATION

The following general information is provided pursuant to ARM 17.8.1210(1).

Company Name: Montana Dakota Utilities Co., Lewis & Clark Station

Mailing Address: 400 North Fourth Street

City: Bismarck State: North Dakota Zip: 58501 

Plant Location: Southwest 1⁄4, Section 9, Township 22 North, Range 59 East, Richland County, Montana

Responsible Official: Andrea Stomberg Phone: (701) 222-7752

Facility Contact Person: Abbie Kresbach Phone: (701) 222-7844 

Primary SIC Code: 4911

Nature of Business: Electric Services

Description of Process: MDU operates a tangential coal-fired boiler capable of burning coal or natural 

gas and associated equipment for generation of electricity.
OP0691-05 2 Decision: 11/03/10

Effective Date: 12/04/10

SECTION II. SUMMARY OF EMISSION UNITS

The emission units regulated by this permit are the following (ARM 17.8.1211):

Emissions 

Unit ID

Description Pollution Control Device/Practice

EU01 Tangential Coal and Natural Gas Fired Boiler Multi-Cyclone and Flooded Disc Wet Scrubber

EU06 Fuel (gasoline) Storage Tank None

EU07 Coal Storage Piles None

EU08 Fugitive Coal, Ash, and Lime Handling None
OP0691-05 3 Decision: 11/03/10

Effective Date: 12/04/10

SECTION III. PERMIT CONDITIONS

The following requirements and conditions are applicable to the facility or to specific emissions units 

located at the facility (ARM 17.8.1211, 1212, and 1213).

A. Facility-Wide

Conditions Rule Citation Rule Description Pollutant/Parameter Limit

A.1 ARM 17.8.105 Testing Requirements Testing Requirements -------

A.2 ARM 17.8.304(1) Visible Air Contaminants Opacity 40%

A.3 ARM 17.8.304(2) Visible Air Contaminants Opacity 20%

A.4 ARM 17.8.308(1) Particulate Matter, Airborne Fugitive Opacity 20%

A.5 ARM 17.8.308(2) Particulate Matter, Airborne Reasonable Precautions -------

A.6 ARM 17.8.308 Particulate Matter, Airborne Reasonable Precaution, 

Construction

20%

A.7 ARM 17.8.309 Particulate Matter, Fuel Burning 

Equipment

Particulate Matter E= 0.882 * H-0.1664 Or

E= 1.026 * H-0.233

A.8 ARM 17.8.310 Particulate Matter, Industrial 

Processes

Particulate Matter E= 4.10 * P0.67 or

E= 55 * P0.11- 40

A.9 ARM 17.8.322(4) Sulfur Oxide Emissions, Sulfur in 

Fuel

Sulfur in Fuel (liquid or 

solid fuels)

1 lb/MMBtu fired

A.10 ARM 17.8.322(5) Sulfur Oxide Emissions, Sulfur in 

Fuel

Sulfur in Fuel (gaseous) 50 gr/100 CF

A.11 ARM 17.8.324(3) Hydrocarbon Emissions, 

Petroleum Products

Gasoline Storage Tanks -------

A.12 ARM 17.8.324 Hydrocarbon Emissions, 

Petroleum Products

65,000 Gallon Capacity -------

A.13 ARM 17.8.324 Hydrocarbon Emissions, 

Petroleum Products

Oil-effluent Water 

Separator

-------

A.14 ARM 17.8.342 NESHAPs General Provisions SSM Plans Submittal

A.15 ARM 17.8.1212 Reporting Requirements Prompt Deviation 

Reporting

-------

A.16 ARM 17.8.1212 Reporting Requirements Compliance Monitoring -------

A.17 ARM 17.8.1207 Reporting Requirements Annual Certification -------

Conditions

A.1. Pursuant to ARM 17.8.105, any person or persons responsible for the emission of any air 

contaminant into the outdoor atmosphere shall, upon written request of the Department, provide 

the facilities and necessary equipment (including instruments and sensing devices) and shall 

conduct tests, emission or ambient, for such periods of time as may be necessary using methods 

approved by the Department.

Compliance demonstration frequencies that list “as required by the Department” refer to ARM 

17.8.105. In addition, for such sources, compliance with limits and conditions listing “as required 

by the Department” as the frequency, is verified annually using emission factors and engineering 

calculations by the Department’s compliance inspectors during the annual emission inventory 

review; in the case of Method 9 tests, compliance is monitored during the regular inspection by the 

compliance inspector.

A.2. Pursuant to ARM 17.8.304(1), MDU shall not cause or authorize emissions to be discharged into 

the outdoor atmosphere from any source installed on or before November 23, 1968, that exhibit an 

opacity of 40% or greater averaged over 6 consecutive minutes, unless otherwise specified by rule 

or in this permit.
OP0691-05 4 Decision: 11/03/10

Effective Date: 12/04/10

A.3. Pursuant to ARM 17.8.304(2), MDU shall not cause or authorize emissions to be discharged into 

the outdoor atmosphere from any source installed after November 23, 1968, that exhibit an opacity 

of 20% or greater averaged over 6 consecutive minutes, unless otherwise specified by rule or in 

this permit.

A.4. Pursuant to ARM 17.8.308(1), MDU shall not cause or authorize the production, handling, 

transportation, or storage of any material unless reasonable precautions to control emissions of 

particulate matter are taken. Such emissions of airborne particulate matter from any stationary 

source shall not exhibit an opacity of 20% or greater averaged over 6 consecutive minutes, unless 

otherwise specified by rule or in this permit.

A.5. Pursuant to ARM 17.8.308(2), MDU shall not cause or authorize the use of any street, road or 

parking lot without taking reasonable precautions to control emissions of airborne particulate 

matter, unless otherwise specified by rule or in this permit.

A.6. Pursuant to ARM 17.8.308, MDU shall not operate a construction site or demolition project unless 

reasonable precautions are taken to control emissions of airborne particulate matter. Such 

emissions of airborne particulate matter from any stationary source shall not exhibit an opacity of 

20% or greater averaged over 6 consecutive minutes, unless otherwise specified by rule or in this 

permit.

A.7. Pursuant to ARM 17.8.309, unless otherwise specified by rule or in this permit, MDU shall not 

cause or authorize particulate matter caused by the combustion of fuel to be discharged from any 

stack or chimney into the outdoor atmosphere in excess of the maximum allowable emissions of 

particulate matter for existing fuel burning equipment and new fuel burning equipment calculated 

using the following equations:

For existing fuel burning equipment (installed before November 23, 1968): 

E =0.882 * H-0.1664

For new fuel burning equipment (installed on or after November 23, 1968):

E =1.026 * H-0.233

Where H is the heat input capacity in million BTU (MMBtu) per hour and E is the maximum 

allowable particulate emissions rate in pounds per MMBtu.

A.8. Pursuant to ARM 17.8.310, unless otherwise specified by rule or in this permit, MDU shall not 

cause or authorize particulate matter to be discharged from any operation, process, or activity into 

the outdoor atmosphere in excess of the maximum hourly allowable emissions of particulate 

matter calculated using the following equations:

For process weight rates up to 30 tons per hour: E = 4.10 * P0.67

For process weight rates in excess of 30 tons per hour: E = 55.0 * P0.11– 40

Where E = rate of emissions in pounds per hour and P = process weight rate in tons per hour.

A.9. Pursuant to ARM 17.8.322(4), MDU shall not burn liquid or solid fuels containing sulfur in excess 

of 1 pound per million BTU fired, unless otherwise specified by rule or in this permit.

A.10. Pursuant to ARM 17.8.322(5), MDU shall not burn any gaseous fuel containing sulfur compounds 

in excess of 50 grains per 100 cubic feet of gaseous fuel, calculated as hydrogen sulfide at 

standard conditions, unless otherwise specified by rule or in this permit.
OP0691-05 5 Decision: 11/03/10

Effective Date: 12/04/10

A.11. Pursuant to ARM 17.8.324(3), MDU shall not load or permit the loading of gasoline into any 

stationary tank with a capacity of 250 gallons or more from any tank truck or trailer, except 

through a permanent submerged fill pipe, unless such tank is equipped with a vapor loss control 

device or is a pressure tank as described in ARM 17.8.324(1), unless otherwise specified by rule 

or in this permit.

A.12. Pursuant to ARM 17.8.324, unless otherwise specified by rule or in this permit, MDU shall not 

place, store or hold in any stationary tank, reservoir or other container of more than 65,000 gallon 

capacity any crude oil, gasoline or petroleum distillate having a vapor pressure of 2.5 pounds per 

square inch absolute or greater under actual storage conditions, unless such tank, reservoir or other 

container is a pressure tank maintaining working pressure sufficient at all times to prevent 

hydrocarbon vapor or gas loss to the atmosphere, or is designed and equipped with a vapor loss 

control device, properly installed, in good working order and in operation. 

A.13. Pursuant to ARM 17.8.324, unless otherwise specified by rule or in this permit, MDU shall not 

use any compartment of any single or multiple-compartment oil-effluent water separator, which 

compartment receives effluent water containing 200 gallons a day or more of any petroleum 

product from any equipment processing, refining, treating, storing or handling kerosene or other 

petroleum product of equal or greater volatility than kerosene, unless such compartment is 

equipped with a vapor loss control device, constructed so as to prevent emission of hydrocarbon 

vapors to the atmosphere, properly installed, in good working order and in operation. 

A.14. Pursuant to ARM 17.8.342 and 40 CFR 63.6, MDU shall submit to the Department a copy of any 

startup, shutdown, and malfunction (SSM) plan required under 40 CFR 63.6(e)(3) within 30 days 

of the effective date of this operating permit (if not previously submitted), within 30 days of the 

compliance date of any new National Emission Standard for Hazardous Air Pollutants 

(NESHAPs) or Maximum Achievable Control Technology (MACT) standard, and within 30 days 

of the revision of any such SSM plan, when applicable. The Department requests submittal of 

such plans in electronic form, when possible.

A.15. MDU shall promptly report deviations from permit requirements including those attributable to 

upset conditions, as upset is defined in the permit. To be considered prompt, deviations shall be 

reported to the Department using the schedule and content as described in Section V.E (unless 

otherwise specified in an applicable requirement) (ARM 17.8.1212).

A.16. On or before February 15 and August 15 of each year, MDU shall submit to the Department the 

compliance monitoring reports required by Section V.D. These reports must contain all 

information required by Section V.D, as well as the information required by each individual 

emissions unit. For the reports due by February 15 of each year, MDU may submit a single report, 

provided that it contains all the information required by Section V.B & V.D. Per ARM 17.8.1207, 

any application form, report, or compliance certification submitted 

pursuant to ARM Title 17, Chapter 8, Subchapter 12 (including 

semiannual monitoring reports), shall contain certification by a 

responsible official of truth, accuracy and completeness. This 

certification and any other certification required under ARM Title 17, 

Chapter 8, Subchapter 12, shall state that, “based on information and 

belief formed after reasonable inquiry, the statements and information 

in the document are true, accurate and complete.”
OP0691-05 6 Decision: 11/03/10

Effective Date: 12/04/10

A.17. By February 15 of each year, MDU shall submit to the Department the compliance certification

required by Section V.B. The annual certification required by Section V.B must include a 

statement of compliance based on the information available which identifies any observed, 

documented or otherwise known instance of noncompliance for each applicable requirement. Per 

ARM 17.8.1207,

any application form, report, or compliance certification submitted 

pursuant to ARM Title 17, Chapter 8, Subchapter 12 (including annual 

certifications), shall contain certification by a responsible official of 

truth, accuracy and completeness. This certification and any other 

certification required under ARM Title 17, Chapter 8, Subchapter 12, 

shall state that, “based on information and belief formed after 

reasonable inquiry, the statements and information in the document 

are true, accurate and complete.”

B. EU01: Tangential Coal-Fired Boiler (Coal and Natural Gas)

Condition(s) Pollutant/Parameter Permit Limit

Compliance Demonstration

Method Frequency

Reporting 

Requiremen

ts

B.1, B.11, 

B.12, B.23, 

B.24, B.26, 

B.34, .B35, 

B.36

Opacity 40% Method 9 As Required 

by the 

Department

Semiannual

Predictive 

Opacity

Ongoing Quarterly

B.2, B.13, 

B.23, B.24, 

B.34, .B35, 

B.36

Particulate Matter 

Fuel Burning

0.17 lb/MMBtu Method 5 Annual Semiannual

0.08 gr/dscf

B.3, B.4, 

B.14, B.15, 

B.16, B.25, 

B.27, B.28, 

B.35, B.36

SO2 Emissions 1.0 lb 

sulfur/MMBtu 

fuel or 2.0 lb 

SO2/MMBtu

Continuous 

Scrubber 

Operations and 

CEMS

Ongoing Semiannual

50 gr sulfur/100 

CF fuel

Record

Keeping

Ongoing Semiannual

B.5, B.17, 

B.28, .B35, 

B.36

NOx

Emissions/Acid 

Rain Provisions

0.40 lb/MMBtu CEMS Ongoing Semiannual

B.6, B.18, 

B.29, .B35, 

B.36

Acid Rain 

Provisions

40 CFR 72-78 40 CFR 72-78 40 CFR 72-78 Semiannual

B.7, B.19, 

B.30, .B35, 

B.36

PM CAM Plan ARM 

17.8.1506

Provisions from 

CAM Plan, 

Appendix I

Ongoing Semiannual

B.8, B.20, 

B.31, .B35, 

B.36

Mercury Emissions 1.5 lb/TBtu MEMS Ongoing Semiannual

B.9, B.21, 

B.32, .B35, 

B.36

Mercury Emission 

Control Equipment

OAI and ACI 

Systems

Log Ongoing Semiannual

B.10, B.22, 

B.33, .B35, 

B.36

40 CFR Part 75 40 CFR Part 75 40 CFR Part 75 Ongoing Semiannual
OP0691-05 7 Decision: 11/03/10

Effective Date: 12/04/10

Conditions

B.1. MDU may not cause or authorize emissions from the Tangential Coal-Fired Boiler (boiler) to be 

discharged into the outdoor atmosphere that exhibit an opacity of 40% or greater averaged over 6 

consecutive minutes (ARM 17.8.304 (2)).

B.2. Particulate matter emissions from the boiler shall not exceed 0.17 lb/MMBtu or 0.08 gr/dscf 

(ARM 17.8.309).

B.3. MDU shall not fire in the boiler liquid or solid fuels containing sulfur in excess of 1.0 lb of 

sulfur/MMBtu fuel or 2.0 lb SO2/MMBtu (ARM 17.8.322(4)).

B.4. MDU shall not fire in the boiler any fuels in excess of 50 grains of sulfur/100 cubic feet of 

gaseous fuel (ARM 17.8.322).

B.5. NOX emissions from the boiler shall not exceed 0.40 lb/MMBtu (40 CFR 76.7).

B.6. MDU shall comply with all applicable standards and limitations, and the reporting, 

recordkeeping, and notification requirements of the Acid Rain Program contained in 40 CFR 72-

78 (40 CFR 72-78).

B.7. MDU shall provide a reasonable assurance of compliance with emission limitations or standards 

for the anticipated range of operations at the Tangential Coal-fired Boiler for PM (ARM 

17.8.1504).

B.8. Beginning January 1, 2010, MDU shall limit mercury emissions from Unit 1 to an emission rate 

equal to or less than 1.5 pounds mercury per trillion British thermal units (lb/TBtu), calculated as 

a rolling 12-month average (ARM 17.8.771).

B.9. MDU shall install an oxidizing agent injection (OAI) system and an activated carbon injection 

(ACI) system. MDU shall implement the operation and maintenance of the OAI and ACI 

systems on or before January 1, 2010 (ARM 17.8.771).

B.10. MDU shall comply with all applicable standards and limitations, and the applicable operating, 

reporting, recordkeeping, and notification requirements contained in 40 CFR Part 75 (ARM 

17.8.771).

Compliance Demonstration

B.11. MDU shall perform a Method 9 opacity test on the boiler annually or as required by the 

Department while the boiler is being fired exclusively on coal to monitor compliance with the 

opacity limitation in Section III.B.1 (ARM 17.8.749 and ARM 17.8.106).

B.12. MDU shall operate and maintain the predictive opacity monitoring system to monitor compliance 

with the opacity limitation in Section III.B.1. The monitoring system operation shall be 

performed in accordance with the Predictive Opacity Appendix E of this permit (40 CFR Part 51, 

Appendix P, §3.9 and ARM 17.8.749).

B.13. MDU shall perform a Method 5 or Method 5B particulate matter test, or another method 

approved by the Department, on the boiler annually to monitor compliance with the particulate 

matter fuel burning limit in Section III.B.2. The testing shall be performed in accordance with 

the Montana Source Test Protocol and Procedures Manual while the boiler is being fired 

exclusively on coal (ARM 17.8.749 and ARM 17.8.106).
OP0691-05 8 Decision: 11/03/10

Effective Date: 12/04/10

B.14. MDU shall operate the scrubber when the boiler is operating to monitor compliance with the 

emission limit in III.B.3 (ARM 17.8.322(6)(c)).

B.15. MDU shall monitor compliance with emission limits in III.B.3 pursuant to the requirements in 40 

CFR Part 75, and the SO2 CEMS Appendix F in this permit (ARM 17.8.1212).

B.16. MDU shall burn only pipeline quality natural gas in the emissions unit when burning gaseous fuel 

to monitor compliance with the emission limit of 50 grains of sulfur/100 cf of gaseous fuel (ARM 

17.8.1213).

B.17. MDU shall monitor compliance with emission limits in III.B.5 pursuant to the requirements in 40 

CFR Part 75, 40 CFR Part 76 and the NOX CEMS Appendix G in this permit (ARM 17.8.1212).

B.18. Compliance monitoring for the applicable requirements contained in 40 CFR 72-78 shall be 

accomplished as described in 40 CFR 72-78 (40 CFR 72-78 and ARM 17.8.1213). 

B.19. MDU shall monitor compliance by following the Compliance Assurance Monitoring (CAM) Plan 

(Appendix I). The CAM Plan, written by MDU in accordance with ARM 17.8.1504 is 

summarized in Appendix I and is available in full upon request by the Department or the facility 

(ARM 17.8.1503 and ARM 17.8.1213).

B.20. In order to monitor compliance with the mercury emission limit in III.B.8, a mercury emissions 

monitoring system (MEMS) shall be installed, certified, and operating on the Unit 1 stack outlet 

on or before January 1, 2010. Said monitor shall comply with the applicable provisions of 40 

CFR Part 75. The MEMS shall also conform to requirements included in Appendix J (ARM 

17.8.1213). 

B.21. Monitoring compliance with the requirements for the installation and operation of OAI and ACI 

systems shall be accomplished through recordkeeping (ARM 17.8.1213).

B.22. Compliance monitoring for the operating, reporting, recordkeeping, and notification requirements 

contained in 40 CFR Part 75 shall be accomplished as described in 40 CFR 75 (ARM 17.8.340 

and 40 CFR 75).

Recordkeeping

B.23. MDU shall maintain, on site, an operations and maintenance log which includes the type of fuel 

fired in the boiler on a daily basis (ARM 17.8.1212).

B.24. All source testing recordkeeping shall be performed in accordance with the Source Test Protocol 

and Procedures Manual, and shall be maintained on site. Method 9 source test reports for opacity 

need not be submitted unless requested by the Department (ARM 17.8.106).

B.25. MDU shall maintain, on site, a log of scrubber downtime and maintenance with respect to boiler 

operations (ARM 17.8.1212).

B.26. MDU shall perform recordkeeping in accordance with the Predictive Opacity Monitoring System 

Appendix E of this permit (ARM 17.8.1212).

B.27. MDU shall verify that only pipeline quality natural gas is being burned in the boiler by 

maintaining a log of the Federal Energy Regulatory Commission (FERC) certifications (ARM 

17.8.1212).
OP0691-05 9 Decision: 11/03/10

Effective Date: 12/04/10

B.28. MDU shall perform recordkeeping as required in Appendix F and Appendix G of this permit as 

well as in accordance with 40 CFR Parts 75 and 76, as applicable (ARM 17.8.1212 and 40 CFR 

Parts 75 and 76).

B.29. MDU shall perform recordkeeping in accordance with 40 CFR 72-78, as applicable and as 

required by Appendices G and H of this permit (40 CFR 72-78 and ARM 17.8.1212).

B.30. Records shall be prepared and data kept in accordance with 40 CFR Part 64 and the CAM 

Appendix I of this permit (ARM 17.8.1212 and 40 CFR 64).

B.31. Records shall be prepared and data kept in accordance with 40 CFR Part 75 and the MEMS 

Appendix J of this permit (ARM 17.8.1212 and 40 CFR 75).

B.32. For any time after January 1, 2010, MDU shall record in a log the date, time, and duration of any 

incident where the OAI and ACI systems are not maintained or operational (ARM 17.8.1212).

B.33. MDU shall perform recordkeeping in accordance with 40 CFR Part 75 (ARM 17.8.1212 and 40 

CFR Part75).

Reporting

B.34. Any compliance source tests shall be submitted in accordance with the Montana Source Test 

Protocol and Procedures Manual (ARM 17.8.106).

B.35. The annual compliance certification report required by Section V.B must contain a certification 

statement for the above applicable requirements (ARM 17.8.1212). 

B.36. The semiannual reporting shall provide (ARM 17.8.1212):

a. A summary of results of any source test that was performed during the reporting period;

b. A summary of the log of fuel type used to fire the boiler;

c. A summary of any downtime and maintenance work performed on the wet scrubber; 

d. Certification of submittal of the quarterly reports required in Appendices E, F, G, and J ;

e. A summary of compliance with 40 CFR Part 64 and Appendix I of this permit;

f. A summary of the log when the OAI and ACI systems were not maintained or 

operational: and

g. A summary of compliance with the requirements of 40 CFR 72-78, as applicable.
OP0691-05 10 Decision: 11/03/10

Effective Date: 12/04/10

C. EU06: Fuel (gasoline) Storage Tank

Condition(s) Pollutant/Parameter Permit Limit Compliance Demonstration

 Method Frequency

Reporting 

Requirement

C.1, C.2, C.3, 

C.4, C.5

40 CFR 63, Subpart 

CCCCCC

40 CFR 63, 

Subpart 

CCCCCC

40 CFR 63,

Subpart 

CCCCCC

Ongoing Semiannual

Conditions

C.1. MDU shall comply with all applicable standards and limitations, and the applicable operating, 

reporting, recordkeeping, and notification requirements contained in 40 CFR 63, Subpart 

CCCCCC (ARM 17.8.340 and 40 CFR 63, Subpart CCCCCC).

Compliance Demonstration

C.2. Compliance monitoring for the operating, reporting, recordkeeping, and notification requirements 

contained in 40 CFR 63, Subpart CCCCCC shall be accomplished as described in 40 CFR 63,

Subpart CCCCCC (ARM 17.8.340 and 40 CFR 63, Subpart CCCCCC).

Recordkeeping

C.3. MDU shall perform recordkeeping in accordance with 40 CFR 63, Subpart CCCCCC (ARM 

17.8.1212 and 40 CFR 63, Subpart CCCCCC). 

Reporting

C.4. The annual compliance certification required by Section V.B must contain a certification 

statement for the above applicable requirements (ARM 17.8.1212). 

C.5. The semiannual reporting shall provide a summary of compliance with 40 CFR 63, Subpart 

CCCCCC.

D. EU07: Coal Storage Piles

Condition(s) Pollutant/Parameter Permit Limit Compliance Demonstration

 Method Frequency

Reporting 

Requirement

D.1, D.2, D.3, 

D.4, D.5, D.6, 

D.7, D.8

Opacity 40% and 

Reasonable 

Precautions

Method 9 Semiannual Semiannual

Visual 

Surveys

Once per 

Calendar 

Week

Semiannual

Conditions

D.1. MDU may not cause or authorize emissions from the Coal Storage Piles to be discharged into the 

outdoor atmosphere that exhibit an opacity of 40% or greater averaged over 6 consecutive 

minutes (ARM 17.8.304(1)).

D.2. MDU shall not cause or authorize the production, handling, transportation, or storage of any 

material unless reasonable precautions to control emissions of particulate matter are taken. Such 

emissions of airborne particulate from any stationary source shall not exhibit an opacity of 20% 

or greater averaged over 6 consecutive minutes (ARM 17.8.308(1)).
OP0691-05 11 Decision: 11/03/10

Effective Date: 12/04/10

Compliance Demonstration

D.3 MDU shall conduct either a semiannual Method 9 source test or a weekly visual survey of visible 

emissions on Coal Storage Piles. Under the visual survey option, once per calendar week, during 

daylight hours, MDU shall visually survey Coal Storage Piles for any visible emissions. If visible 

emissions are observed during the visual survey, MDU must take corrective action to contain or 

minimize the source of emissions. Following the corrective action, MDU shall again visually 

survey the Coal Storage Piles for any visible emissions. If visible emissions remain, MDU shall 

conduct a Method 9 source test. The Method 9 source test must begin within one hour of any 

observation of visible emissions following the corrective action. The person conducting the 

visual survey shall record the results of the survey (including any corrective action taken and the 

results of any Method 9 source test performed) in a log, Conducting a visual survey does not 

relieve MDU of the liability for a violation determined using Method 9 (ARM 17.8.101(27)). 

If the visual surveys are not performed once per calendar week as specified above during the 

reporting period, then MDU shall perform the Method 9 source tests on Coal Storage Piles for 

that reporting period. 

Method 9 source tests must be performed in accordance with the Montana Source Test Protocol 

and Procedures Manual, except that prior notification of the test is not required. Each observation 

period must be a minimum of 6 minutes unless any one reading is 20% or greater, then the 

observation period must be a minimum of 20 minutes or until a violation of the standard has been 

documented, whichever is a shorter period of time (ARM 17.8.1213).

Recordkeeping

D.4. All source test recordkeeping shall be performed in accordance with the test method used and the 

Montana Source Test Protocol and Procedures Manual (ARM 17.8.106). 

D.5 If visual surveys are performed, MDU shall maintain a log to verify that the visual surveys were 

performed as specified in Section III.D.3. Each log entry must include the date, time, results of 

survey (and results of subsequent Method 9, if applicable), and observer’s initials If any 

corrective action is required, the time, date, observer’s initials, and any preventive or corrective 

action taken must be recorded in the log (ARM 17.8.1212).

Reporting

D.6. All source test reports must be submitted to the Department in accordance with the Montana 

Source Test Protocol and Procedures Manual (ARM 17.8.106).

D.7. The annual compliance certification report required by Section V.B must contain a certification 

statement for the above applicable requirements (ARM 17.8.1212). 

D.8. The semiannual reporting shall provide (ARM 17.8.1212): 

a. A summary of the visual survey log as required by Section III.D.3 or Method 9 source test 

results, and 

b. A summary of the log of corrective actions maintained as required by Section III.D.5.
OP0691-05 12 Decision: 11/03/10

Effective Date: 12/04/10

E. EU08: Fugitive Coal, Ash, and Lime Handling

Condition(s) Pollutant/Parameter Permit Limit Compliance Demonstration

 Method Frequency

Reporting 

Requirement

E.1, E.2, E.3, 

E.4, E.5, E.6, 

E.7, E.8

Opacity 40% and 

Reasonable 

Precautions

Method 9 Semiannual Semiannual

Visual 

Surveys

Once per 

Calendar 

Week

Semiannual

Conditions

E.1. MDU may not cause or authorize emissions from the fugitive coal, ash, and lime handling to be 

discharged into the outdoor atmosphere that exhibit an opacity of 40% or greater averaged over 6 

consecutive minutes (ARM 17.8.304(1)).

E.2. MDU shall not cause or authorize the production, handling, transportation, or storage of any 

material unless reasonable precautions to control emissions of particulate matter are taken. Such 

emissions of airborne particulate from any stationary source shall not exhibit an opacity of 20% 

or greater averaged over 6 consecutive minutes (ARM 17.8.308(1)).

Compliance Demonstration

E.3 MDU shall conduct either a semiannual Method 9 source test or a weekly visual survey of visible 

emissions on the coal, ash, and lime handling. Under the visual survey option, once per calendar 

week, during daylight hours, MDU shall visually survey the coal, ash, and lime handling for any 

visible emissions. If visible emissions are observed during the visual survey, MDU must take 

corrective action to contain or minimize the source of emissions. Following the corrective action, 

MDU shall again visually survey the coal, ash, and lime handling for any visible emissions. If 

visible emissions remain, MDU shall conduct a Method 9 source test. The Method 9 source test 

must begin within one hour of any observation of visible emissions following the corrective 

action. The person conducting the visual survey shall record the results of the survey (including 

any corrective action taken and the results of any Method 9 source test performed) in a log, 

Conducting a visual survey does not relieve MDU of the liability for a violation determined using 

Method 9 (ARM 17.8.101(27)). 

If the visual surveys are not performed once per calendar week as specified above during the 

reporting period, then MDU shall perform the Method 9 source tests on the coal, ash, and lime 

handling for that reporting period. 

Method 9 source tests must be performed in accordance with the Montana Source Test Protocol 

and Procedures Manual, except that prior notification of the test is not required. Each observation 

period must be a minimum of 6 minutes unless any one reading is 20% or greater, then the 

observation period must be a minimum of 20 minutes or until a violation of the standard has been 

documented, whichever is a shorter period of time (ARM 17.8.1213).

Recordkeeping

E.4. All source test recordkeeping shall be performed in accordance with the test method used and the 

Montana Source Test Protocol and Procedures Manual (ARM 17.8.106). 
OP0691-05 13 Decision: 11/03/10

Effective Date: 12/04/10

E.5. If visual surveys are performed, MDU shall maintain a log to verify that the visual surveys were 

performed as specified in Section III.E.3. Each log entry must include the date, time, results of 

survey (and results of subsequent Method 9, if applicable), and observer’s initials If any 

corrective action is required, the time, date, observer’s initials, and any preventive or corrective 

action taken must be recorded in the log (ARM 17.8.1212).

Reporting

E.6. All source test reports must be submitted to the Department in accordance with the Montana 

Source Test Protocol and Procedures Manual (ARM 17.8.106).

E.7. The annual compliance certification report required by Section V.B must contain a certification 

statement for the above applicable requirements (ARM 17.8.1212). 

E.8. The semiannual reporting shall provide (ARM 17.8.1212): 

a. A summary of the visual survey log as required by Section III.E.3 or Method 9 source 

test results; and

b. A summary of the log of corrective actions maintained as specified by Section III.E.5.
OP0691-05 14 Decision: 11/03/10

Effective Date: 12/04/10

SECTION IV. NON-APPLICABLE REQUIREMENTS

Air Quality Administrative Rules of Montana (ARM) and Federal Regulations identified as not applicable 

to the facility or to a specific emissions unit at the time of the permit issuance are listed below (ARM 

17.8.1214). The following list does not preclude the need to comply with any new requirements that may 

become applicable during the permit term.

A. Facility-Wide

The following table contains non-applicable requirements which are administrated by the Air Resources 

Management Bureau of the Department of Environmental Quality.

Rule Citation Reason

State Federal

ARM 17.8.321, ARM 

17.8.323, ARM 17.8.610

These rules are not applicable because the facility is not 

listed in the source category cited in the rules.

ARM 17.8.320 These rules are not applicable because the facility does not 

have the specific emissions unit cited in the rules.

40 CFR 60, Subparts C, Ca, Cb

40 CFR 60, Subparts D, Da, Db, Dc

40 CFR 60, Subparts E-J

40 CFR 60, Subparts K, Ka, Kb 

40 CFR 60, Subparts L-Z

40 CFR 60, Subparts AA-EE

40 CFR 60, Subparts GG-HH

40 CFR 60, Subparts KK-NN

40 CFR 60, Subparts PP-XX

40 CFR 60, Subparts AAA-BBB

40 CFR 60, Subpart DDD

40 CFR 60, Subparts FFF-LLL

40 CFR 60, Subparts NNN-VVV

40 CFR 60, Subpart WWW

40 CFR 60, Subparts AAAA-FFFF

40 CFR 60, Subparts IIII-KKKK

40 CFR 61, Subparts B-F

40 CFR 61, Subparts H-L

40 CFR 61, Subparts N-R

40 CFR 61, Subpart T

40 CFR 61, Subparts V-W

40 CFR 61, Subpart Y

40 CFR 61, Subpart BB

40 CFR 61, Subpart FF

These requirements are not applicable because the facility 

is not an affected source as defined in these regulations.

40 CFR 63, Subparts F-I

40 CFR 63, Subpart J

40 CFR 63, Subparts L-Q

40 CFR 63, Subparts Q-U

40 CFR 63, Subparts W-Y

40 CFR 63, Subparts AA-EE

40 CFR 63, Subparts GG-MM

40 CFR 63, Subparts OO-YY

40 CFR 63, Subparts CCC-EEE

40 CFR 63, Subparts GGG-JJJ

40 CFR 63, Subparts LLL-RRR

These requirements are not applicable because the facility 

is not an affected source as defined in these regulations.
OP0691-05 15 Decision: 11/03/10

Effective Date: 12/04/10

Rule Citation Reason

State Federal

40 CFR 63, Subparts TTT-VVV

40 CFR 63, Subpart XXX

40 CFR 63, Subpart AAAA

40 CFR 63, Subparts CCCC-KKKK

40 CFR 63, Subparts MMMMNNNNN

40 CFR 63, Subparts PPPPP-TTTTT

40 CFR 63, Subpart WWWWW

40 CFR 63, Subparts YYYYYZZZZZ

40 CFR 63, Subpart BBBBBB

40 CFR 63, Subparts DDDDDDHHHHHH

40 CFR 63, Subparts LLLLLLTTTTTT

40 CFR 63, Subparts WWWWWWXXXXXX

40 CFR 82, Subparts A-E

40 CFR 82, Subparts G-H

B. Emission Units

The Operating Permit #OP0691-04 renewal application identified applicable and non-applicable 

requirements. After review of the application, the Department listed all non-applicable requirements in 

Section IV.A. These requirements relate to each specific unit, as well as facility wide.
OP0691-05 16 Decision: 11/03/10

Effective Date: 12/04/10

SECTION V. GENERAL PERMIT CONDITIONS

A. Compliance Requirements

ARM 17.8, Subchapter 12, Operating Permit Program §1210(2)(a)-(c)&(e), §1206(6)(c)&(b)

1. The permittee must comply with all conditions of the permit. Any noncompliance with the 

terms or conditions of the permit constitutes a violation of the Montana Clean Air Act, and may 

result in enforcement action, permit modification, revocation and reissuance, or termination, or 

denial of a permit renewal application under ARM Title 17, Chapter 8, Subchapter 12.

2. The filing of a request by the permittee for a permit modification, revocation and reissuance, or 

termination, or of a notification of planned changes or anticipated noncompliance does not stay 

any permit condition.

3. It shall not be a defense for a permittee in an enforcement action that it would have been 

necessary to halt or reduce the permitted activity in order to maintain compliance with the 

conditions of the permit. If appropriate, this factor may be considered as a mitigating factor in 

assessing a penalty for noncompliance with an applicable requirement if the source 

demonstrates that both the health, safety or environmental impacts of halting or reducing 

operations would be more serious than the impacts of continuing operations, and that such 

health, safety or environmental impacts were unforeseeable and could not have otherwise been 

avoided.

4. The permittee shall furnish to the Department, within a reasonable time set by the Department 

(not to be less than 15 days), any information that the Department may request in writing to 

determine whether cause exists for modifying, revoking and reissuing, or terminating the 

permit, or to determine compliance with the permit. Upon request, the permittee shall also 

furnish to the Department copies of those records that are required to be kept pursuant to the 

terms of the permit. This subsection does not impair or otherwise limit the right of the 

permittee to assert the confidentiality of the information requested by the Department, as 

provided in 75-2-105, MCA.

5. Any schedule of compliance for applicable requirements with which the source is not in 

compliance with at the time of permit issuance shall be supplemental to, and shall not sanction 

noncompliance with, the applicable requirements on which it was based.

6. For applicable requirements that will become effective during the permit term, the source shall 

meet such requirements on a timely basis unless a more detailed plan or schedule is required by 

the applicable requirement or the Department.

B. Certification Requirements

ARM 17.8, Subchapter 12, Operating Permit Program §1207 and §1213(7)(a)&(c)-(d)

1. Any application form, report, or compliance certification submitted pursuant to ARM Title 17, 

Chapter 8, Subchapter 12, shall contain certification by a responsible official of truth, accuracy 

and completeness. This certification and any other certification required under ARM Title 17, 

Chapter 8, Subchapter 12, shall state that, based on information and belief formed after 

reasonable inquiry, the statements and information in the document are true, accurate and 

complete.
OP0691-05 17 Decision: 11/03/10

Effective Date: 12/04/10

2. Compliance certifications shall be submitted by February 15 of each year, or more frequently if 

otherwise specified in an applicable requirement or elsewhere in the permit. Each certification 

must include the required information for the previous calendar year (i.e., January 1 –

December 31).

3. Compliance certifications shall include the following:

a. The identification of each term or condition of the permit that is the basis of the 

certification;

b. The identification of the method(s) or other means used by the owner or operator for 

determining the status of compliance with each term and condition during the certification 

period, consistent with ARM 17.8.1212;

c. The status of compliance with each term and condition for the period covered by the 

certification, including whether compliance during the period was continuous or 

intermittent (based on the method or means identified in ARM 17.8.1213(7)(c)(ii), as 

described above); and

d. Such other facts as the Department may require to determine the compliance status of the 

source.

4. All compliance certifications must be submitted to the Environmental Protection Agency, as 

well as to the Department, at the addresses listed in the Notification Addresses Appendix of this 

permit.

C. Permit Shield

ARM 17.8, Subchapter 12, Operating Permit Program §1214(1)-(4)

1. The applicable requirements and non-federally enforceable requirements are included and 

specifically identified in this permit and the permit includes a precise summary of the 

requirements not applicable to the source. Compliance with the conditions of the permit shall 

be deemed compliance with any applicable requirements and any non-federally enforceable 

requirements as of the date of permit issuance.

2. The permit shield described in 1 above shall remain in effect during the appeal of any permit 

action (renewal, revision, reopening, or revocation and reissuance) to the Board of 

Environmental Review (Board), until such time as the Board renders its final decision.

3. Nothing in this permit alters or affects the following:

a. The provisions of Sec. 7603 of the FCAA, including the authority of the administrator 

under that section;

b. The liability of an owner or operator of a source for any violation of applicable 

requirements prior to or at the time of permit issuance;

c. The applicable requirements of the Acid Rain Program, consistent with Sec. 7651g(a) of 

the FCAA;

d. The ability of the administrator to obtain information from a source pursuant to Sec. 7414 

of the FCAA;
OP0691-05 18 Decision: 11/03/10

Effective Date: 12/04/10

e. The ability of the Department to obtain information from a source pursuant to the Montana 

Clean Air Act, Title 75, Chapter 2, MCA;

f. The emergency powers of the Department under the Montana Clean Air Act, Title 75, 

Chapter 2, MCA; and

g. The ability of the Department to establish or revise requirements for the use of Reasonably 

Available Control Technology (RACT) as defined in ARM Title 17, Chapter 8. However, 

if the inclusion of a RACT into the permit pursuant to ARM Title 17, Chapter 8, 

Subchapter 12, is appealed to the Board, the permit shield, as it applies to the source’s 

existing permit, shall remain in effect until such time as the Board has rendered its final 

decision.

4. Nothing in this permit alters or affects the ability of the Department to take enforcement action 

for a violation of an applicable requirement or permit term demonstrated pursuant to ARM 

17.8.106, Source Testing Protocol.

5. Pursuant to ARM 17.8.132, for the purpose of submitting a compliance certification, nothing in 

these rules shall preclude the use, including the exclusive use, of any credible evidence or 

information relevant to whether a source would have been in compliance. However, when 

compliance or noncompliance is demonstrated by a test or procedure provided by permit or 

other applicable requirements, the source shall then be presumed to be in compliance or 

noncompliance unless that presumption is overcome by other relevant credible evidence.

6. The permit shield will not extend to minor permit modifications or changes not requiring a 

permit revision (see Sections I & J).

7. The permit shield will extend to significant permit modifications and transfer or assignment of

ownership (see Sections K & O).

D. Monitoring, Recordkeeping, and Reporting Requirements

ARM 17.8, Subchapter 12, Operating Permit Program §1212(2)&(3)

1. Unless otherwise provided in this permit, the permittee shall maintain compliance monitoring 

records that include the following information:

a. The date, place as defined in the permit, and time of sampling or measurement;

b. The date(s) analyses were performed;

c. The company or entity that performed the analyses;

d. The analytical techniques or methods used;

e. The results of such analyses; and

f. The operating conditions at the time of sampling or measurement.

2. The permittee shall retain records of all required monitoring data and support information for a 

period of at least 5 years from the date of the monitoring sample, measurement, report, or 

application. Support information includes all calibration and maintenance records and all 

original strip-chart recordings for continuous monitoring instrumentation, and copies of all 

reports required by the permit. All monitoring data, support information, and required reports 
OP0691-05 19 Decision: 11/03/10

Effective Date: 12/04/10

and summaries may be maintained in computerized form at the plant site if the information is 

made available to Department personnel upon request, which may be for either hard copies or 

computerized format. Strip-charts must be maintained in their original form at the plant site 

and shall be made available to Department personnel upon request.

3. The permittee shall submit to the Department, at the addresses located in the Notification 

Addresses Appendix of this permit, reports of any required monitoring by February 15 and 

August 15 of each year, or more frequently if otherwise specified in an applicable requirement 

or elsewhere in the permit. The monitoring report submitted on February 15 of each year must

include the required monitoring information for the period of July 1 through December 31 of 

the previous year. The monitoring report submitted on August 15 of each year must include the 

required monitoring information for the period of January 1 through June 30 of the current year. 

All instances of deviations from the permit requirements must be clearly identified in such 

reports. All required reports must be certified by a responsible official, consistent with ARM 

17.8.1207.

E. Prompt Deviation Reporting

ARM 17.8, Subchapter 12, Operating Permit Program §1212(3)(c)

The permittee shall promptly report deviations from permit requirements, including those attributable 

to upset conditions as defined in the permit, the probable cause of such deviations, and any corrective 

actions or preventive measures taken. To be considered prompt, deviations shall be reported to the 

Department within the following timeframes (unless otherwise specified in an applicable 

requirement):

1. For deviations which may result in emissions potentially in violation of permit limitations:

a. An initial phone notification (or faxed or electronic notification) describing the incident 

within 24 hours (or the next business day) of discovery; and,

b. A follow-up written, faxed, or electronic report within 30 days of discovery of the deviation 

that describes the probable cause of the reported deviation and any corrective actions or 

preventative measures taken.

2. For deviations attributable to malfunctions, deviations shall be reported to the Department in 

accordance with the malfunction reporting requirements under ARM 17.8.110; and

3. For all other deviations, deviations shall be reported to the Department via a written, faxed, or 

electronic report within 90 days of discovery (as determined through routine internal review by 

the permittee).

Prompt deviation reports do not need to be resubmitted with regular semiannual (or other routine) 

reports, but may be referenced by the date of submittal.

F. Emergency Provisions

ARM 17.8, Subchapter 12, Operating Permit Program §1201(13) and §1214(5), (6)&(8)

1. An “emergency” means any situation arising from sudden and reasonably unforeseeable events 

beyond the control of the source, including acts of God, which situation requires immediate 

corrective action to restore normal operation and causes the source to exceed a technologybased emission limitation under this permit due to the unavoidable increases in emissions 

attributable to the emergency. An emergency shall not include noncompliance to the extent 

caused by improperly designed equipment, lack of reasonable preventive maintenance, careless 

or improper operation, or operator error.
OP0691-05 20 Decision: 11/03/10

Effective Date: 12/04/10

2. An emergency constitutes an affirmative defense to an action brought for noncompliance with a 

technology-based emission limitation if the permittee demonstrates through properly signed, 

contemporaneous logs, or other relevant evidence, that:

a. An emergency occurred and the permittee can identify the cause(s) of the emergency;

b. The permitted facility was at the time being properly operated;

c. During the period of the emergency the permittee took all reasonable steps to minimize 

levels of emissions that exceeded the emission standards or other requirements in the 

permit; and 

d. The permittee submitted notice of the emergency to the Department within 2 working days 

of the time when emission limitations were exceeded due to the emergency. This notice 

fulfills the requirements of ARM 17.8.1212(3)(c). This notice must contain a description 

of the emergency, any steps taken to mitigate emissions, and corrective actions taken.

3. These emergency provisions are in addition to any emergency, malfunction or upset provision 

contained in any applicable requirement.

G. Inspection and Entry

ARM 17.8, Subchapter 12, Operating Permit Program §1213(3)&(4)

1. Upon presentation of credentials and other requirements as may be required by law, the 

permittee shall allow the Department, the administrator, or an authorized representative 

(including an authorized contractor acting as a representative of the Department or the 

administrator) to perform the following:

a. Enter the premises where a source required to obtain a permit is located or emissionsrelated activity is conducted, or where records must be kept under the conditions of the 

permit;

b. Have access to and copy, at reasonable times, any records that must be kept under the 

conditions of the permit;

c. Inspect at reasonable times any facilities, emission units, equipment (including monitoring 

and air pollution control equipment), practices, or operations regulated or required under 

the permit; and

d. As authorized by the Montana Clean Air Act and rules promulgated thereunder, sample or 

monitor, at reasonable times, any substances or parameters at any location for the purpose 

of assuring compliance with the permit or applicable requirements.

2. The permittee shall inform the inspector of all workplace safety rules or requirements at the 

time of inspection. This section shall not limit in any manner the Department’s statutory right 

of entry and inspection as provided for in 75-2-403, MCA.

H. Fee Payment

ARM 17.8, Subchapter 12, Operating Permit Program §1210(2)(f) and ARM 17.8, Subchapter 5, Air 

Quality Permit Application, Operation, and Open Burning Fees §505(3)-(5) (STATE ONLY)

1. The permittee must pay application and operating fees, pursuant to ARM Title 17, Chapter 8, 

Subchapter 5.
OP0691-05 21 Decision: 11/03/10

Effective Date: 12/04/10

2. Annually, the Department shall provide the permittee with written notice of the amount of the 

fee and the basis for the fee assessment. The air quality operation fee is due 30 days after 

receipt of the notice, unless the fee assessment is appealed pursuant to ARM 17.8.511. If any 

portion of the fee is not appealed, that portion of the fee that is not appealed is due 30 days after 

receipt of the notice. Any remaining fee, which may be due after the completion of an appeal, 

is due immediately upon issuance of the Board’s decision or upon completion of any judicial 

review of the Board’s decision.

3. If the permittee fails to pay the required fee (or any required portion of an appealed fee) within 

90 days of the due date of the fee, the Department may impose an additional assessment of 15% 

of the fee (or any required portion of an appealed fee) or $100, whichever is greater, plus 

interest on the fee (or any required portion of an appealed fee), computed at the interest rate 

established under 15-31-510(3), MCA.

I. Minor Permit Modifications

ARM 17.8, Subchapter 12, Operating Permit Program §1226(3)&(11)

1. An application for a minor permit modification need only address in detail those portions of the 

permit application that require revision, updating, supplementation, or deletion, and may 

reference any required information that has been previously submitted.

2. The permit shield under ARM 17.8.1214 will not extend to any minor modifications processed 

pursuant to ARM 17.8.1226.

J. Changes Not Requiring Permit Revision

ARM 17.8, Subchapter 12, Operating Permit Program §1224(1)-(3), (5)&(6)

1. The permittee is authorized to make changes within the facility as described below, provided 

the following conditions are met:

a. The proposed changes do not require the permittee to obtain a Montana Air Quality Permit

under ARM Title 17, Chapter 8, Subchapter 7;

b. The proposed changes are not modifications under Title I of the FCAA, or as defined in 

ARM Title 17, Chapter 8, Subchapters 8, 9, or 10;

c. The emissions resulting from the proposed changes do not exceed the emissions allowable 

under this permit, whether expressed as a rate of emissions or in total emissions;

d. The proposed changes do not alter permit terms that are necessary to enforce applicable 

emission limitations on emission units covered by the permit; and

e. The facility provides the administrator and the Department with written notification at least 

7 days prior to making the proposed changes.

2. The permittee and the Department shall attach each notice provided pursuant to 1.e above to 

their respective copies of this permit.

3. Pursuant to the conditions above, the permittee is authorized to make Section 502(b)(10) 

changes, as defined in ARM 17.8.1201(30), without a permit revision. For each such change, 

the written notification required under 1.e above shall include a description of the change 

within the source, the date on which the change will occur, any change in emissions, and any 

permit term or condition that is no longer applicable as a result of the change.
OP0691-05 22 Decision: 11/03/10

Effective Date: 12/04/10

4. The permittee may make a change not specifically addressed or prohibited by the permit terms 

and conditions without requiring a permit revision, provided the following conditions are met:

a. Each proposed change does not weaken the enforceability of any existing permit 

conditions;

b. The Department has not objected to such change;

c. Each proposed change meets all applicable requirements and does not violate any existing 

permit term or condition; and

d. The permittee provides contemporaneous written notice to the Department and the 

administrator of each change that is above the level for insignificant emission units as 

defined in ARM 17.8.1201(22) and 17.8.1206(3), and the written notice describes each 

such change, including the date of the change, any change in emissions, pollutants emitted, 

and any applicable requirement that would apply as a result of the change.

5. The permit shield authorized by ARM 17.8.1214 shall not apply to changes made pursuant to 

ARM 17.8.1224(3) and (5), but is applicable to terms and conditions that allow for increases 

and decreases in emissions pursuant to ARM 17.8.1224(4).

K. Significant Permit Modifications

ARM 17.8, Subchapter 12, Operating Permit Program §1227(1), (3)&(4)

1. The modification procedures set forth in 2 below must be used for any application requesting a 

significant modification of this permit. Significant modifications include the following:

a. Any permit modification that does not qualify as either a minor modification or as an 

administrative permit amendment;

b. Every significant change in existing permit monitoring terms or conditions;

c. Every relaxation of permit reporting or recordkeeping terms or conditions that limit the 

Department’s ability to determine compliance with any applicable rule, consistent with the 

requirements of the rule; or

d. Any other change determined by the Department to be significant.

2. Significant modifications shall meet all requirements of ARM Title 17, Chapter 8, including 

those for applications, public participation, and review by affected states and the administrator, 

as they apply to permit issuance and renewal, except that an application for a significant permit 

modification need only address in detail those portions of the permit application that require 

revision, updating, supplementation or deletion.

3. The permit shield provided for in ARM 17.8.1214 shall extend to significant modifications.

L. Reopening for Cause

ARM 17.8, Subchapter 12, Operating Permit Program §1228(1)&(2)

This permit may be reopened and revised under the following circumstances:

1. Additional applicable requirements under the FCAA become applicable to the facility when the 

permit has a remaining term of 3 or more years. Reopening and revision of the permit shall be 

completed not later than 18 months after promulgation of the applicable requirement. No 

reopening is required under ARM 17.8.1228(1)(a) if the effective date of the applicable 
OP0691-05 23 Decision: 11/03/10

Effective Date: 12/04/10

requirement is later than the date on which the permit is due to expire, unless the original 

permit or any of its terms or conditions have been extended pursuant to ARM 17.8.1220(12) or 

17.8.1221(2);

2. Additional requirements (including excess emission requirements) become applicable to an 

affected source under the Acid Rain Program. Upon approval by the administrator, excess 

emission offset plans shall be deemed incorporated into the permit;

3. The Department or the administrator determines that the permit contains a material mistake or 

that inaccurate statements were made in establishing the emission standards or other terms or 

conditions of the permit; or

4. The administrator or the Department determines that the permit must be revised or revoked and 

reissued to ensure compliance with the applicable requirements.

M. Permit Expiration and Renewal

ARM 17.8, Subchapter 12, Operating Permit Program §1210(2)(g), §1220(11)&(12), and §1205(2)(d)

1. This permit is issued for a fixed term of 5 years.

2. Renewal of this permit is subject to the same procedural requirements that apply to permit 

issuance, including those for application, content, public participation, and affected state and 

administrator review.

3. Expiration of this permit terminates the permittee’s right to operate unless a timely and 

administratively complete renewal application has been submitted consistent with ARM 

17.8.1221 and 17.8.1205(2)(d). If a timely and administratively complete application has been 

submitted, all terms and conditions of the permit, including the application shield, remain in 

effect after the permit expires until the permit renewal has been issued or denied.

4. For renewal, the permittee shall submit a complete air quality operating permit application to 

the Department not later than 6 months prior to the expiration of this permit, unless otherwise 

specified. If necessary to ensure that the terms of the existing permit will not lapse before 

renewal, the Department may specify, in writing to the permittee, a longer time period for 

submission of the renewal application. Such written notification must be provided at least 1 

year before the renewal application due date established in the existing permit.

N. Severability Clause

ARM 17.8, Subchapter 12, Operating Permit Program §1210(2)(i)&(l)

1. The administrative appeal or subsequent judicial review of the issuance by the Department of 

an initial permit under this subchapter shall not impair in any manner the underlying 

applicability of all applicable requirements, and such requirements continue to apply as if a 

final permit decision had not been reached by the Department.

2. If any provision of a permit is found to be invalid, all valid parts that are severable from the 

invalid part remain in effect. If a provision of a permit is invalid in one or more of its 

applications, the provision remains in effect in all valid applications that are severable from the 

invalid applications.
OP0691-05 24 Decision: 11/03/10

Effective Date: 12/04/10

O. Transfer or Assignment of Ownership

ARM 17.8, Subchapter 12, Operating Permit Program §1225(2)&(4)

1. If an administrative permit amendment involves a change in ownership or operational control, 

the applicant must include in its request to the Department a written agreement containing a 

specific date for the transfer of permit responsibility, coverage and liability between the current 

and new permittee.

2. The permit shield provided for in ARM17.8.1214 shall not extend to administrative permit 

amendments.

P. Emissions Trading, Marketable Permits, Economic Incentives

ARM 17.8, Subchapter 12, Operating Permit Program §1226(2)

Notwithstanding ARM 17.8.1226(1) and (7), minor air quality operating permit modification 

procedures may be used for permit modifications involving the use of economic incentives, 

marketable permits, emissions trading, and other similar approaches, to the extent that such minor 

permit modification procedures are explicitly provided for in the Montana State Implementation Plan 

or in applicable requirements promulgated by the administrator.

Q. No Property Rights Conveyed

ARM 17.8, Subchapter 12, Operating Permit Program §1210(2)(d)

This permit does not convey any property rights of any sort, or any exclusive privilege.

R. Testing Requirements

ARM 17.8, Subchapter 1, General Provisions §105

The permittee shall comply with ARM 17.8.105.

S. Source Testing Protocol

ARM 17.8, Subchapter 1, General Provisions §106

The permittee shall comply with ARM 17.8.106.

T. Malfunctions

ARM 17.8, Subchapter 1, General Provisions §110

The permittee shall comply with ARM 17.8.110.

U. Circumvention

ARM 17.8, Subchapter 1, General Provisions §111

The permittee shall comply with ARM 17.8.111.

V. Motor Vehicles

ARM 17.8, Subchapter 3, Emission Standards §325

The permittee shall comply with ARM 17.8.325.
OP0691-05 25 Decision: 11/03/10

Effective Date: 12/04/10

W. Annual Emissions Inventory

ARM 17.8, Subchapter 5, Air Quality Permit Application, Operation and Open Burning Fees §505 

(STATE ONLY)

The permittee shall supply the Department with annual production and other information for all 

emission units necessary to calculate actual or estimated actual amount of air pollutants emitted 

during each calendar year. Information shall be gathered on a calendar-year basis and submitted to 

the Department by the date required in the emission inventory request, unless otherwise specified in 

this permit. Information shall be in the units required by the Department.

X. Open Burning

ARM 17.8, Subchapter 6, Open Burning §604, 605 and 606

The permittee shall comply with ARM 17.8.604, 605 and 606.

Y. Montana Air Quality Permits

ARM 17.8, Subchapter 7, Permit, Construction and Operation of Air Contaminant Sources §745 and 

764 (ARM 17.8.745(1) and 764(1)(b) are STATE ENFORCEABLE ONLY until approval by the 

EPA as part of the SIP)

1. Except as specified, no person shall construct, install, modify or use any air contaminant source 

or stack associated with any source without first obtaining a permit from the Department or 

Board. A permit is not required for those sources or stacks as specified by ARM 

17.8.744(1)(a)-(k).

2. The permittee shall comply with ARM 17.8.743, 744, 745, 748, and 764.

3. ARM 17.8.745(1) specifies de minimis changes as construction or changed conditions of 

operation at a facility holding a Montana Air Quality Permit (MAQP) issued under Chapter 8 

that does not increase the facility’s potential to emit by more than 15 tons per year of any 

pollutant, except (STATE ENFORCEABLE ONLY until approved by the EPA as part of the 

SIP):

a. Any construction or changed condition that would violate any condition in the facility’s 

existing MAQP or any applicable rule contained in Chapter 8 is prohibited, except as 

provided in ARM 17.8.745(2);

b. Any construction or changed conditions of operation that would qualify as a major 

modification under Subchapters 8, 9 or 10 of Chapter 8;

c. Any construction or changed condition of operation that would affect the plume rise or 

dispersion characteristic of emissions that would cause or contribute to a violation of an 

ambient air quality standard or ambient air increment as defined in ARM 17.8.804;

d. Any construction or improvement project with a potential to emit more than 15 tons per 

year may not be artificially split into smaller projects to avoid Montana Air Quality 

Permitting; or

e. Emission reductions obtained through offsetting within a facility are not included when 

determining the potential emission increase from construction or changed conditions of 

operation, unless such reductions are made federally enforceable.
OP0691-05 26 Decision: 11/03/10

Effective Date: 12/04/10

4. Any facility making a de minimis change pursuant to ARM 17.8.745(1) shall notify the 

Department if the change would include a change in control equipment, stack height, stack 

diameter, stack gas temperature, source location or fuel specifications, or would result in an 

increase in source capacity above its permitted operation or the addition of a new emission unit. 

The notice must be submitted, in writing, 10 days prior to start up or use of the proposed de 

minimis change, or as soon as reasonably practicable in the event of an unanticipated 

circumstance causing the de minimis change, and must include the information requested in 

ARM 17.8.745(1) (STATE ENFORCEABLE ONLY until approval by the EPA as part of the 

SIP).

Z. National Emission Standard for Asbestos

40 CFR, Part 61, Subpart M

The permittee shall not conduct any asbestos abatement activities except in accordance with 40 CFR 

61, Subpart M (National Emission Standard for Hazardous Air Pollutants for Asbestos).

AA. Asbestos

ARM 17.74, Subchapter 3, General Provisions and Subchapter 4, Fees

The permittee shall comply with ARM 17.74.301, et seq., and ARM 17.74.401, et seq. (State only)

BB.Stratospheric Ozone Protection – Servicing of Motor Vehicle Air Conditioners

40 CFR, Part 82, Subpart B

If the permittee performs a service on motor vehicles and this service involves ozone-depleting 

substance/refrigerant in the motor vehicle air conditioner (MVAC), the permittee is subject to all the 

applicable requirements as specified in 40 CFR 82, Subpart B.

CC. Stratospheric Ozone Protection – Recycling and Emission Reductions

40 CFR, Part 82, Subpart F

The permittee shall comply with the standards for recycling and emission reductions in 40 CFR 82, 

Subpart F, except as provided for MVACs in Subpart B:

1. Persons opening appliances for maintenance, service, repair, or disposal must comply with the 

required practices pursuant to §82.156;

2. Equipment used during the maintenance, service, repair or disposal of appliances must comply 

with the standards for recycling and recovery equipment pursuant to §82.158;

3. Persons performing maintenance, service, repair or disposal of appliances must be certified by 

an approved technical certification program pursuant to §82.161;

4. Persons disposing of small appliances, MVACs and MVAC-like (as defined at §82.152) 

appliances must comply with recordkeeping requirements pursuant to §82.166;

5. Persons owning commercial or industrial process refrigeration equipment must comply with the 

leak repair requirements pursuant to §82.156; and

6. Owners/operators of appliances normally containing 50 or more pounds of refrigerant must 

keep records of refrigerant purchased and added to such appliances pursuant to §82.166.
OP0691-05 27 Decision: 11/03/10

Effective Date: 12/04/10

DD. Emergency Episode Plan

The permittee shall comply with the requirements contained in Chapter 9.7 of the State of Montana 

Air Quality Control Implementation Plan.

Each major source emitting 100 tons per year located in a Priority I Air Quality Control Region, shall 

submit to the Department a legally enforceable Emergency Episode Action Plan (EEAP) that details 

how the source will curtail emissions during an air pollutant emergency episode. The industrial 

EEAP shall be in accordance with the Department’s EEAP and shall be submitted according to a 

timetable developed by the Department, following Priority I reclassification.

EE.Definitions

Terms not otherwise defined in this permit or in the Definitions and Abbreviations Appendix of this 

permit, shall have the meaning assigned to them in the referenced regulations.
OP0691-05 28 Decision: 11/03/10

Effective Date: 12/04/10

APPENDICES
OP0691-05 A-1 Decision: 11/03/10

Effective Date: 12/04/10

Appendix A INSIGNIFICANT EMISSION UNITS

Disclaimer: The information in this appendix is not State or Federally enforceable, but is presented to 

assist MDU, the permitting authority, inspectors, and the public.

Pursuant to ARM 17.8.1201(22)(a), an insignificant emissions unit means any activity or emissions unit 

located within a source that: (i) has a potential to emit less than 5 tons per year of any regulated pollutant; 

(ii) has a potential to emit less than 500 pounds per year of lead; (iii) has a potential to emit less than 500 

pounds per year of hazardous air pollutants listed pursuant to Section 7412 (b) of the FCAA; and (iv) is 

not regulated by an applicable requirement, other than a generally applicable requirement that applies to 

all emission units subject to Subchapter 12.

List of Insignificant Activities:

The following table of insignificant sources and/or activities was provided by MDU. Because there are 

no requirements to update such a list, the emission units and/or activities may change from those specified 

in the table.

Emissions Unit ID Description

IEU02 Heating Boiler

IEU03 Diesel Fire Pump Engine

IEU04 Emergency Generator

IEU05 Miscellaneous Space Heaters

IEU09 Coal Tripper House

IEU10 Lime Storage Silo

IEU11 Plant Roads

IEU12 Vehicle Air Conditioning

IEU13 Activated Carbon Injection Silo

IEU14 Coal Conveyor Dust Collection Devices

 
OP0691-05 B-1 Decision: 11/03/10

Effective Date: 12/04/10

Appendix B DEFINITIONS and ABBREVIATIONS

"Act" means the Clean Air Act, as amended, 42 U.S. 7401, et seq.

"Administrative permit amendment" means an air quality operating permit revision that:

(a) corrects typographical errors;

(b) identifies a change in the name, address or phone number of any person identified in the air 

quality operating permit, or identifies a similar minor administrative change at the source;

(c) requires more frequent monitoring or reporting by MDU;

(d) requires changes in monitoring or reporting requirements that the Department deems to be no 

less stringent than current monitoring or reporting requirements;

(e) allows for a change in ownership or operational control of a source if the Department has 

determined that no other change in the air quality operating permit is necessary, consistent 

with ARM 17.8.1225; or

(f) incorporates any other type of change which the Department has determined to be similar to 

those revisions set forth in (a)-(e), above.

"Applicable requirement" means all of the following as they apply to emission units in a source 

requiring an air quality operating permit (including requirements that have been promulgated or approved 

by the Department or the administrator through rule making at the time of issuance of the air quality 

operating permit, but have future-effective compliance dates, provided that such requirements apply to 

sources covered under the operating permit):

(a) any standard, rule, or other requirement, including any requirement contained in a consent 

decree or judicial or administrative order entered into or issued by the Department, that is 

contained in the Montana state implementation plan approved or promulgated by the 

administrator through rule making under Title I of the FCAA;

(b) any federally enforceable term, condition or other requirement of any Montana Air Quality 

Permit issued by the Department under Subchapters 7, 8, 9 and 10 of this chapter, or pursuant 

to regulations approved or promulgated through rule making under Title I of the FCAA, 

including parts C and D;

(c) any standard or other requirement under Section 7411 of the FCAA, including Section

7411(d);

(d) any standard or other requirement under Section 7412 of the FCAA, including any 

requirement concerning accident prevention under Section 7412(r)(7), but excluding the 

contents of any risk management plan required under Section 7412(r);

(e) any standard or other requirement of the acid rain program under Title IV of the FCAA or 

regulations promulgated thereunder;

(f) any requirements established pursuant to Section 7661c(b) or Section 7414(a)(3) of the 

FCAA;
OP0691-05 B-2 Decision: 11/03/10

Effective Date: 12/04/10

(g) any standard or other requirement governing solid waste incineration, under Section 7429 of 

the FCAA;

(h) any standard or other requirement for consumer and commercial products, under Section

7511b(e) of the FCAA;

(i) any standard or other requirement for tank vessels, under Section 7511b(f) of the FCAA;

(j) any standard or other requirement of the regulations promulgated to protect stratospheric 

ozone under Title VI of the FCAA, unless the administrator determines that such 

requirements need not be contained in an air quality operating permit;

(k) any national ambient air quality standard or increment or visibility requirement under part C 

of Title I of the FCAA, but only as it would apply to temporary sources permitted pursuant to 

Section 7661c(e) of the FCAA; or

(l) any federally enforceable term or condition of any air quality open burning permit issued by 

the Department under Subchapter 6.

"Department" means the Montana Department of Environmental Quality.

"Emissions unit" means any part or activity of a stationary source that emits or has the potential to emit 

any regulated air pollutant or any pollutant listed under Section 7412(b) of the FCAA. This term is not 

meant to alter or affect the definition of the term "unit" for purposes of Title IV of the FCAA.

"FCAA" means the Federal Clean Air Act, as amended.

"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 the Montana state implementation plan, and any permit requirement established pursuant to 40 

CFR 52.21 or under regulations approved pursuant to 40 CFR 51, Subpart I, including operating permits 

issued under an EPA approved program that is incorporated into the Montana state implementation plan 

and expressly requires adherence to any permit issued under such program.

"Fugitive emissions" means those emissions which could not reasonably pass through a stack, chimney, 

vent, or other functionally equivalent opening.

"General air quality operating permit" or "general permit" means an air quality operating permit that 

meets the requirements of ARM 17.8.1222, covers multiple sources in a source category, and is issued in 

lieu of individual permits being issued to each source.

"Hazardous air pollutant" means any air pollutant listed as a hazardous air pollutant pursuant to 

Section 112(b) of the FCAA. 

"Non-federally enforceable requirement" means the following as they apply to emission units in a 

source requiring an air quality operating permit:

(a) any standard, rule, or other requirement, including any requirement contained in a consent 

decree, or judicial or administrative order entered into or issued by the Department, that is not 

contained in the Montana state implementation plan approved or promulgated by the 

administrator through rule making under Title I of the FCAA;
OP0691-05 B-3 Decision: 11/03/10

Effective Date: 12/04/10

(b) any term, condition or other requirement contained in any Montana Air Quality Permit issued 

by the Department under Subchapters 7, 8, 9 and 10 of this chapter that is not federally 

enforceable;

(c) does not include any Montana ambient air quality standard contained in Subchapter 2 of this 

chapter.

"Permittee" means the owner or operator of any source subject to the permitting requirements of this 

subchapter, as provided in ARM 17.8.1204, that holds a valid air quality operating permit or has 

submitted a timely and complete permit application for issuance, renewal, amendment, or modification 

pursuant to this subchapter.

"Regulated air pollutant" means the following:

(a) nitrogen oxides or any volatile organic compounds;

(b) any pollutant for which a national ambient air quality standard has been promulgated;

(c) any pollutant that is subject to any standard promulgated under Section 7411 of the FCAA;

(d) any Class I or II substance subject to a standard promulgated under or established by Title VI 

of the FCAA; or

(e) any pollutant subject to a standard or other requirement established or promulgated under 

Section 7412 of the FCAA, including but not limited to the following:

(i) any pollutant subject to requirements under Section 7412(j) of the FCAA. If the 

administrator fails to promulgate a standard by the date established in Section 7412(e) of 

the FCAA, any pollutant for which a subject source would be major shall be considered 

to be regulated on the date 18 months after the applicable date established in Section 

7412(e) of the FCAA; 

(ii) any pollutant for which the requirements of Section 7412(g)(2) of the FCAA have been 

met but only with respect to the individual source subject to Section 7412(g)(2) 

requirement.

"Responsible official" means one of the following:

(a) For a corporation: a president, secretary, treasurer, or vice-president of the corporation in 

charge of a principal business function, or any other person who performs similar policy or 

decision-making functions for the corporation, or a duly authorized representative of such 

person if the representative is responsible for the overall operation of one or more 

manufacturing, production, or operating facilities applying for or subject to a permit and 

either:

(i) the facilities employ more than 250 persons or have gross annual sales or expenditures 

exceeding $25 million (in second quarter 1980 dollars); or 

(ii) the delegation of authority to such representative is approved in advance by the 

Department.
OP0691-05 B-4 Decision: 11/03/10

Effective Date: 12/04/10

(b) For a partnership or sole proprietorship: a general partner or the proprietor, respectively.

(c) For a municipality, state, federal, or other public agency: either a principal executive officer 

or ranking elected official. For the purposes of this part, a principal executive officer of a 

federal agency includes the chief executive officer having responsibility for the overall 

operations of a principal geographic unit of the agency (e.g., a regional administrator of the 

environmental protection agency).

(d) For affected sources: the designated representative in so far as actions, standards, 

requirements, or prohibitions under Title IV of the FCAA or the regulations promulgated 

thereunder are concerned, and the designated representative for any other purposes under this 

subchapter.
OP0691-05 B-5 Decision: 11/03/10

Effective Date: 12/04/10

Abbreviations:

ARM Administrative Rules of Montana

ASTM American Society of Testing Materials

BACT Best Available Control Technology

BDT bone dry tons

BTU British Thermal Unit

CFR Code of Federal Regulations

CO carbon monoxide

DEQ Department of Environmental Quality

dscf dry standard cubic foot

dscfm dry standard cubic foot per minute

EEAP Emergency Episode Action Plan

EPA U.S. Environmental Protection Agency

EPA Method Test methods contained in 40 CFR 60, Appendix A

EU emissions unit

FCAA Federal Clean Air Act

gr grains

HAP hazardous air pollutant

IEU insignificant emissions unit

Mbdft thousand board feet

Method 5 40 CFR 60, Appendix A, Method 5

Method 9 40 CFR 60, Appendix A, Method 9

MMbdft million board feet

MMBTU million British Thermal Units

NOx oxides of nitrogen

NO2 nitrogen dioxide

O2 oxygen

Pb lead

PM particulate matter

PM10 particulate matter less than 10 microns in size

psi pounds per square inch

scf standard cubic feet

SIC Source Industrial Classification

SO2 sulfur dioxide

SOx oxides of sulfur

tpy tons per year

U.S.C. United States Code

VE visible emissions

VOC volatile organic compound
OP0691-05 C-1 Decision: 11/03/10

Effective Date: 12/04/10

Appendix C NOTIFICATION ADDRESSES

Compliance Notifications:

Montana Department of Environmental Quality

Permitting and Compliance Division

Air Resources Management Bureau

P.O. Box 200901

Helena, MT 59620-0901

United States EPA

Air Program Coordinator

Region VIII, Montana Office

10 W. 15th Street, Suite 3200

Helena, MT 59626

Permit Modifications:

Montana Department of Environmental Quality

Permitting and Compliance Division

Air Resources Management Bureau

P.O. Box 200901

Helena, MT 59620-0901

Office of Partnerships and Regulatory Assistance

Air and Radiation Program

US EPA Region VIII 8P-AR

1595 Wynkoop Street

Denver, CO 80202-1129
OP0691-05 D-1 Decision: 11/03/10

Effective Date: 12/04/10

Appendix D AIR QUALITY INSPECTOR INFORMATION

Disclaimer: The information in this appendix is not State or Federally enforceable but is presented to 

assist MDU, permitting authority, inspectors, and the public.

1. Direction to Plant:

The facility is located 1.5 miles south of Sidney, Montana and is accessed by traveling South on 

Highway 16 from Sidney and turning east onto Highway 23. Highway 23 borders the facility 

boundary. 

2. Safety Equipment Required:

All visitors are required to check in when arriving on site. Hard hats and safety glasses are required 

at all times except in office areas or the CEMS shelter. All visitors are required to be accompanied by 

plant personnel. In situations such as during RATA testing, it is permissible for visitors to go 

unattended between the office area and the CEMS shelter as needed. Hard hats and safety glasses are 

available if needed.

3. Facility Plot Plan:

The facility plot plan was submitted with the initial operating permit application on June 10, 1996, 

and is available for review at the Department offices in Helena.
OP0691-05 E-1 Decision: 11/03/10

Effective Date: 12/04/10

Appendix E PREDICTIVE OPACITY

Nothing in this appendix is intended to alter the requirements in the Acid Rain Appendix.

1. Pursuant to 40 CFR 51, Appendix P, § 3.9, MDU shall maintain and operate a continuous 

predictive opacity monitoring system as approved by the Department. The predictive monitoring 

system shall be used to demonstrate compliance with the applicable 6-minute opacity limit.

The predictive opacity monitoring system shall include, at a minimum, instrumentation on the 

following parameters:

a. 4 Scrubber Throat Nozzle Flows

b. Scrubber Slurry Flow to Disk

c. Disk Position

d. Scrubber Differential Pressure

e. Recycling Slurry pH

f. Recycling Slurry Density (Specific Gravity)

g. Mist Eliminator Sump Level

h. Steam Flow

i. Dust Collector Differential Pressure

j. Flue Gas Temperature (air heater outlet)

k. Flue Gas Oxygen (at air heater outlet)

l. Dust Collector Compartments in Service

The parameters monitored must be used to predict the scrubber disk position and the opacity 

readings.

2. MDU shall maintain the equation for calculating opacity on a six minute average. Any changes 

to the predictive opacity equation must be submitted to the Department for approval. MDU shall 

also submit data as necessary to support the change requested.

3. MDU shall maintain the scrubber disk position calculations. Any changes to the disk position 

calculations must be submitted to the Department. MDU shall also submit data necessary to 

support the change requested.

4. MDU shall maintain records for a minimum of 5 years of the log sheets, computerized data, 

analysis, and calculations used to prepare the required reports.

5. MDU shall submit reports to the Department containing all 6-minute averages equal to or greater 

than the applicable opacity limit. The summary reports shall be submitted quarterly to the 

Department.

The quarterly reports must be postmarked by the 30th day after the end of each quarter.
OP0691-05 F-1 Decision: 11/03/10

Effective Date: 12/04/10

Appendix F SO2 CEMS

Nothing in this appendix is intended to alter the requirements in the Acid Rain Appendix.

1. Pursuant to 40 CFR Part 75, MDU shall calibrate, maintain, and operate continuous monitoring 

systems. Heat input shall be determined as required in the 40 CFR 75, Appendix F and the NOx

CEMS Appendix.

Except for system breakdowns, repairs, calibration checks, and zero and span adjustments 

required pursuant to 40 CFR Part 75, all continuous monitoring systems shall be in continuous 

operation.

2. The monitor range is set at 0 ppm to 500 ppm. The monitor must have an over-range alarm. 

MDU shall report any exceedances of the range to the Department. An exceedance of the range 

is a violation of the 2 lb of SO2/mmBtu emission limit.

3. MDU shall maintain records for a minimum of 5 years of the log sheets, computerized data, 

analysis, and calculations used to prepare the required reports.

4. MDU shall submit quarterly to the Department containing the following information:

a. MDU shall maintain records of the occurrence and duration of any startup, shutdown, or 

malfunction in the operation of an affected facility; any malfunction of the air pollution 

control equipment; or any periods during which the continuous monitoring system is 

inoperative.

b. MDU shall submit an excess emissions and monitoring systems performance report and/or a 

summary report form (see paragraph (c) below) to the Department. Written reports of excess 

emissions greater than 2 lbs of SO2/mmBtu shall include the following information:

i. The magnitude of excess emissions, any conversion factor(s) used, and the date and time 

of commencement and completion of each time period of excess emissions. The process 

operating time during the reporting period.

ii. Any period of time when the monitor range is exceeded. This shall include the date and 

time of commencement and completion of each time period the monitor is exceeding the 

range. The process operating time during the reporting period. These periods shall be 

considered periods of excess emissions.

iii. Specific identification of each period of excess emissions that occurs during startups, 

shutdowns, and malfunctions of the affected facility. The nature and cause of any 

malfunction (if known), the corrective action taken or preventative measures adopted.

iv. The date and time identifying each period during which the continuous monitoring 

system was inoperative except for zero and span checks and the nature of the system 

repairs or adjustments.

v. When no excess emissions have occurred or the continuous monitoring system(s) have 

not been inoperative, repaired, or adusted, such information shall be stated in the report.
OP0691-05 F-2 Decision: 11/03/10

Effective Date: 12/04/10

c. The summary report form shall contain the information and be in the format shown in Figure 

1. The summary report form shall be submitted:

i. If the total duration of excess emissions for the reporting period is less than 1 percent of 

the total operating time for the reporting period and CEMS downtime for the reporting 

period is less than 5 percent of the total operating time for the reporting period, only the 

summary report form shall be submitted and the excess emission report described in 

section (b) above need not be submitted unless requested.

ii. If the total duration of excess emissions for the reporting period is 1 percent or greater of 

the total operating time for the reporting period or the total CEMS downtime for the 

reporting period is 5 percent or great of the total operating time for the reporting period, 

the summary report form and the excess emission report described in section (b) above 

shall both be submitted.

Figure 1 – Summary Report

Gaseous Excess Emission and Monitoring System Performance

Pollutant:

Reporting period dates: From to _______

Emission Limitation::

Monitor Manufacturer and Model No.:

Date of Latest CEMS Certification or Audit:

Process Unit(s) Description:

Total source operating time in reporting period:

Emission Data Summary

1. Duration of excess emission in reporting period due to:

a. Startup/shutdown

b. Control equipment problems

c. Process problems

d. Other known causes

e. Unknown causes

2. Total duration of excess emissions.

3. Total duration of excess emission x (100) = % excess emissions

Total Boiler Operating Time

CEMS Performance Summary

1. CEMS downtime in reporting period due to:

a. Monitor equipment malfunctions

b. Non-Monitor equipment malfunctions

c. Quality assurance calibrations

d. Other known causes

e. Unknown causes

2. Total CEMS Downtime when the boiler is operating (nearest quarter hour).

3. Total CEMS downtime when the boiler is operating x 100 = % downtime

Total boiler operating time.

4. Total boiler operating time (nearest quarter hour).
OP0691-05 F-3 Decision: 11/03/10

Effective Date: 12/04/10

5. MDU shall submit quarterly reports to the Department containing the following information for 

each month of the quarter:

a. Tons of emissions calculated as the sum of Eh= K x Ch x Qh where Eh = emission rate (lb/hr), 

K = 1.66 x.10-7(lb/scf)/ppm (SO2), Ch = Measured Pollutant Concentration (ppmwet), and Qh

= Measured Stack Gas Flow Rate (SCFHwet); and

b. A summary report including the information identified in 40 CFR § 75.64 (a)(3) in writing 

which includes: Tons (rounded to the nearest tenth) of SO2 emitted during the quarter and 

cumulative SO2 emissions for calendar year.

The quarterly reports must be postmarked by the 30th day after the end of the calendar quarter.

6. MDU shall submit copies of all RATAs performed to the Department in accordance with ARM 

17.8.106, Source Test Protocol and Procedures Manual.

7. MDU shall submit copies of each monitoring plan revision which results in the need to recertify 

the CEMS.
OP0691-05 G-1 Decision: 11/03/10

Effective Date: 12/04/10

Appendix G NOx CEMS

Nothing in this appendix is intended to alter the requirements in the Acid Rain Appendix.

1. Except for system breakdowns, repairs, calibration checks, and zero and span adjustments 

required pursuant to 40 CFR Part 75, all continuous monitoring systems shall be in continuous 

operation.

2. MDU shall conduct a “Standard Practice for Ultimate Analysis of Coal and Coke”, ASTM 

D5291-92, at a minimum of once per year for each type of coal used.

3. MDU shall determine the gross calorific value (GVC) of the fuels using ASTM D2015-91, 

“Standard Test Method for Gross Calorific Value of Coal and Coke by the Adiabatic Bomb 

Calorimeter” or other method as identified in 40 CFR Part 75, Appendix F, §3.3.6.2, at a 

minimum of once per year for each type of coal used.

4. MDU shall conduct a weekly fuel analysis using ASTM D4239-85 or other method approved by 

the Department.

5. MDU shall maintain records for a minimum of 5 years of the log sheets, computerized data, 

analysis, and calculations used to prepare the required reports.

6. MDU shall submit quarterly to the Department containing the following information:

a. MDU shall maintain records of the occurrence and duration of any startup, shutdown, or 

malfunction in the operation of an affected facility; any malfunction of the air pollution 

control equipment; or any periods during which the continuous monitoring system is 

inoperative.

b. MDU shall submit a monitoring systems performance report to the Department in the 

format shown in Figure 1.
OP0691-05 G-2 Decision: 11/03/10

Effective Date: 12/04/10

Figure 1 – Summary Report

Gaseous Excess Emission and Monitoring System Performance

Pollutant:

Reporting period dates: From to _______

Emission Limitation::

Monitor Manufacturer and Model No.:

Date of Latest CEMS Certification or Audit:

Process Unit(s) Description:

Total source operating time in reporting period:

CEMS Performance Summary

1. CEMS downtime in reporting period due to:

a. Monitor equipment malfunctions

b. Non-Monitor equipment malfunctions

c. Quality assurance calibrations

d. Other known causes

e. Unknown causes

2. Total CEMS Downtime when the boiler is operating (nearest quarter hour).

3. Total CEMS downtime when the boiler is operating x 100 = % downtime

Total boiler operating time.

4. Total boiler operating time (nearest quarter hour).

7. MDU shall submit quarterly reports to the Department containing the following information for 

each month of the quarter:

a. Monthly average coal analysis;

b. Coal consumption;

c. Other fuels combusted and the amount;

d. Tons of emissions calculated as the sum of Eh = K x Ch x Qh where Eh = emission rate 

(lb/hr), K = 1.19 x 10-7(lb/scf)/ppm (NOx), Ch = Measured Pollutant Concentration 

(ppmwet), and Qh where Eh = Measured Stack Gas Flow Rate (SCFHwet); and

e. A summary report including the information identified in 40 CFR §75.64 (a)(4) through 

(6) in writing which includes:

i. Average NOx emission rate (lb/mmBtu, rounded to the nearest hundredth) during 

the quarter and cumulative NOx emission rate for calendar year.

ii. Tons of CO2 emitted during quarter and cumulative CO2 for calendar year.

iii. Total heat input (mmBtu) for quarter and cumulative heat input for calendar year.

The quarterly reports must be postmarked by the 30th day after the end of the calendar quarter.

8. MDU shall submit copies of all RATAs performed to the Department in accordance with ARM 

17.8.106, Source Test Protocol and Procedures.

9. MDU shall submit copies of each monitoring plan revision which results in the need to recertify 

the CEMS.
OP0691-05 H-1 Decision: 11/03/10

Effective Date: 12/04/10 

Appendix H ACID RAIN
OP0691-05 I-1 Decision: 11/03/10

Effective Date: 12/04/10 

Appendix I Compliance Assurance Monitoring (CAM) Plan

Table 

– 1 MONITORING APPROACH

Indicator #8

Disk 

Deviation

Disk position 

deviation 

from 

predicted Calculated 

from 

indicators one through seven

Comparison 

reviewed after 

cleaning of 

disk

Measured 

continuously

Instantaneous 

data compiled 

into 6-minute 

average

Daily average 

calculated 

from 6-minute 

averages

Indicator #7

Dust Collector 

Compartments 

in Service

2 to 4 

Compartments

Limit switch 

on control 

dampers

Corrective 

action taken if 

false 

indication is 

observed

Measured

Continuously

Instantaneous 

data compiled 

into 6-minute 

average

Instantaneous 

data used for 

calculations

Indicator #6

Flue Gas O2

2 to 7 %

O2 Monitor 

located after 

economizer 

before the air 

heater

Calibrated 

Monthly

Measured

Continuously

Instantaneous 

data compiled 

into 6-minute 

average

Instantaneous 

data used for 

calculations

Indicator #5

Flue Gas 

Temperature

200 to 420 

o

F

Duct 

Temperature 

probe in gas 

duct at Dust 

Collector

Inspect during 

one outage per 

year and clean 

well as 

necessary

Measured

Continuously

Instantaneous 

data compiled 

into 6-minute 

average

Instantaneous 

data used for 

calculations

Indicator #4

Dust Collector 

Flow

50000 to 300000 

scfm

Calculated from 

Dust Collector 

differential 

pressure, 

temperature 

corrected

Cleaned every 6- months, calibrated 

yearly

Measured

Continuously

Instantaneous data 

compiled into 6- minute average

Instantaneous data 

used for 

calculations

Indicator #3

Differential 

Pressure

10 to 14 IWC

Differential 

pressure 

monitor, 

sensors 

located above 

and below 

disk

Calibrated 

every 6- months , 

pressure taps 

cleaned 

weekly

Measured

Continuously

Instantaneous 

data compiled 

into 6-minute 

average

Instantaneous 

data used 

Indicator #2

Flooded Disk 

Position

0 to 18 in.

Transmitter 

located at disk 

shaft

Inspected and 

Calibrated at 

6-month 

outages

Measured

Continuously

Instantaneous 

data compiled 

into 6-minute 

average

Instantaneous 

data used 

Indicator #1

Scrubber 

Slurry Flow

1500 to 4000 

gpm

Flow meters 

located after 

Pump 

Discharge at 

disk inlet and 

disk

Periodic 

Inspections

Measured

Continuously

Instantaneous 

data 

compiled into 

6-minute 

average

Instantaneous 

data used 

Indicator

Range

Data 

Collection 

Method

QA/QC 

Practices

Monitoring 

Frequency

Data 

Collection 

Frequency

Averaging 

period
OP0691-05 I-2 Decision: 11/03/10

Effective Date: 12/04/10 

Although the complete hard copy of Appendix I is not included in the permit, the contents of Appendix I, 

MDU’s CAM plan remain as applicable requirements as stated in the Title V Operating Permit. To receive a 

hard copy of this appendix, please contact one of the following:

The Department of Environmental Quality

Permitting and Compliance Division

Air Resources Management Bureau

1520 E. Sixth Ave.

P.O. Box 200901

Helena, Montana 59620-0901

Bureau Phone (406) 444-3490

OR

Montana Dakota Utilities Co.

Lewis & Clark Station

400 North Fourth Street

Bismarck, North Dakota 58501

Phone (701) 222-7844
OP0691-05 J-1 Decision: 11/03/10

Effective Date: 12/04/10 

Appendix J MEMS

MEMS

a. MDU shall install, calibrate, certify, maintain, and operate a MEMS to monitor and 

record the rate of mercury emissions discharged into the atmosphere from all mercury 

emitting generating units (units) as defined in the Administrative Rules of Montana 

17.8.740.

(1) The MEMS shall be comprised of equipment as required in 40 CFR 75.81(a) and 

defined in 40 CFR 72.2.

(2) The MEMS shall conform to all applicable requirements of 40 CFR Part 75. 

(3) The MEMS data will be used to demonstrate compliance with the emission 

limitations contained in Section II.A.4. 

b. MDU shall prepare, maintain and submit a written MEMS Monitoring Plan to the 

Department. 

(1) The monitoring plan shall contain sufficient information on the MEMS and the 

use of data derived from these systems to demonstrate that all the gaseous 

mercury stack emissions from each unit are monitored and reported.

(2) Whenever MDU makes a replacement, modification, or change in a MEMS or 

alternative monitoring system under 40 CFR 75 subpart E, including a change in 

the automated data acquisition and handling system (DAHS) or in the flue gas 

handling system, that affects information reported in the monitoring plan (e.g. a 

change to a serial number for a component of a monitoring system), then the 

owner or operator shall update the monitoring plan. 

(3) If any monitoring plan information requires an update pursuant to Section b.(2), 

submission of the written monitoring plan update shall be completed prior to or 

concurrent with the submittal of the quarterly report required in c. below for the 

quarter in which the update is required.

(4) The initial submission of the Monitoring Plan to the Department shall include a 

copy of a written Quality Assurance/Quality Control (QA/QC) Plan as detailed in 

40 CFR 75 Appendix B, Section 1. Subsequently, the QA/QC Plan need only be 

submitted to the Department when it is substantially revised. Substantial 

revisions can include items such as changes in QA/QC processes resulting from 

rule changes, modifications in the frequency or timing of QA/QC procedures, or 

the addition/deletion of equipment or procedures.

(5) The Monitoring Plan shall include, at a minimum, the following information: 

(a) Facility summary including:

(i) A description of each mercury emitting generating unit at the 

facility.
OP0691-05 J-2 Decision: 11/03/10

Effective Date: 12/04/10 

(ii) Maximum and average loads (in megawatts (MW)) with fuels 

combusted and fuel flow rates at the maximum and average 

loads for each unit.

(iii) A description of each unit’s air pollution control equipment and 

a description of the physical characteristics of each unit’s stack.

(b) Mercury emission control summary including a description of control 

strategies, equipment, and design process rates.

(c) MEMS description, including:

(i) Identification and description of each monitoring component in 

the MEMS including manufacturer and model identifications; 

monitoring method descriptions; and normal operating scale and 

units descriptions. Descriptions of stack flow, diluent gas, and 

moisture monitors (if used) in the system must be described in 

addition to the mercury monitor or monitors.

(ii) A description of the normal operating process for each monitor 

including a description of all QA/QC checks 

(iii) A description of the methods that will be employed to verify and 

maintain the accuracy and precision of the MEMS calibration 

equipment.

(iv) Identification and description of the DAHS, including major 

hardware and software components, conversion formulas, 

constants, factors, averaging processes, and missing data 

substitution procedures.

(v) A description of all initial certification and ongoing 

recertification tests and frequencies; as well as all accuracy 

auditing tests and frequencies.

(d) The Maximum Potential Concentration (MPC), Maximum Expected 

Concentration (MEC), span value, and range value as applicable and as 

defined in 40 CFR 75 Appendix A, 2.1.7.

(e) Examples of all data reports required in c. below.

c. MDU shall submit written, Quarterly Mercury Monitoring Reports. The reports shall be 

postmarked to the Department by the 30th day after the end of each quarter and shall 

include, at a minimum, the following:

(1) Mercury emissions. The reports shall include:

(a) The 12-month rolling average pounds per trillion British thermal units 

(lb/TBtu) emission rate for each month of the reporting quarter. The 

rolling 12-month basis is an average of the last 12 individual calendar 

monthly averages, with each monthly average calculated at the end of 

each calendar month;
OP0691-05 J-3 Decision: 11/03/10

Effective Date: 12/04/10 

(b) The monthly average lb/TBtu mercury emission rate for each month of 

the quarter; 

(c) The total heat input to the boiler (in TBtu) for each 12-month rolling 

period of the quarter; and

(2) Mercury excess emissions. The report shall describe the magnitude of excess 

mercury emissions experienced during the quarter, including:

(a) The date and time of commencement and completion of each period of 

excess emissions. Periods of excess emissions shall be defined as those 

emissions calculated on a rolling 12-month basis which are greater than 

the limitation established in II.A.4. 

(b) The nature and cause of each period of excess emissions and the 

corrective action taken or preventative measures adopted in response.

(c) If no periods of excess mercury emissions were experienced during the

quarter, the report shall state that information.

(3) MEMS performance. The report shall describe:

(a) The number of operating hours that the MEMS was unavailable or not 

operating within quality assurance limits (monitor downtime) during the 

reporting quarter, broken down by the following categories:

Monitor equipment malfunctions;

Non-Monitor equipment malfunctions;

Quality assurance calibration;

Other known causes; and

Unknown causes.

(b) The percentage of unit operating time that the MEMS was unavailable or 

not operating within quality assurance limits (monitor downtime) during 

the reporting quarter. The percentage of monitor downtime in each 

calendar quarter shall be calculated according to the following formula:

% x100

OpHours

MEMSDownHours MEMSDowntime where

MEMSDowntime% = Percentage of unit operating hours 

classified as MEMS monitor downtime 

during the reporting quarter

MEMSDownHours = Total number of hours of MEMS 

monitor downtime during the reporting 

quarter

OpHours = Total number of hours the unit operated 

during the reporting quarter.
OP0691-05 J-4 Decision: 11/03/10

Effective Date: 12/04/10 

(c) For any reporting quarter in which monitor downtime exceeds 10%, a 

description of each time period during which the MEMS was inoperative 

or operating in a manner defined in 40 CFR Part 75 as “out of control.” 

Each description must include the date, start and end times, total 

downtime (in hours), the reason for the system downtime, and any 

necessary corrective actions that were taken. In addition, the report shall 

describe the values used for any periods when missing data substitution 

was necessary as detailed in 40 CFR 75.30, et seq. 

(4) The quarterly report shall include the results of any QA/QC audits, checks, or 

tests conducted to satisfy the requirements of 40 CFR Part 75 Appendices A, B 

or K.

(5) Compliance certification. Each quarterly report shall contain a certification 

statement signed by the facility’s responsible official based on reasonable inquiry 

of those persons with primary responsibility for ensuring that all of the unit's 

emissions are correctly and fully monitored. The certification shall indicate:

(a) Whether the monitoring data submitted were recorded in accordance 

with the applicable requirements of 40 CFR Part 75 including the 

QA/QC procedures and specifications of that part and its appendices, and 

any such requirements, procedures and specifications of an applicable 

excepted or approved alternative monitoring method as represented in 

the approved Monitoring Plan.

(b) That for all hours where data are substituted in accordance with 40 CFR 

75.38, the add-on mercury emission controls were operating within the 

range of parameters listed in the quality-assurance plan for the unit, and 

that the substitute values do not systematically underestimate mercury 

emissions.

(6) The format of each component of the quarterly report may be negotiated with the 

Department’s representative to accommodate the capabilities and formats of the 

facility’s DAHS.

(7) Each quarterly report must be received by the Department within 30 days 

following the end of each calendar reporting period (January-March, April-June, 

July-September, and October-December). 

(8) The electronic data reporting detailed in 40 CFR Part 75 shall not be required 

unless Montana is able to receive and process data in an electronic format.

d. MDU shall maintain a file of all measurements and performance testing results from the 

MEMS; all MEMS performance evaluations; all MEMS or monitoring device calibration 

checks and audits; and records of all adjustments and maintenance performed on these 

systems or devices recorded in a permanent form suitable for inspection. The file shall be 

retained on site for at least five years following the date of such measurements and 

reports. MDU shall make these records available for inspection by the Department and 

shall supply these records to the Department upon request.