Air Operating Permits

Operating permits are required for any air pollution source that has the potential to emit pollutants in excess of the major source thresholds. An operating permit identifies all applicable requirements. Operating permits include information on which pollutants are being released, how much is released, and what steps, if any, that the facility is required to take to reduce the pollution. 

Operating permits are legally-enforceable documents written by the department. Operating permits are especially useful for businesses covered by more than one part of the Clean Air Act and additional state requirements, since information about all of a source’s air pollution is consolidated in one place. 

There are two types of operating permits issued by the department - Intermediate operating permits and Part 70 operating permits. Not all facilities will need an operating permit, but all facilities need to know their status and obligations. Operating permits are valid for a five year period.

Operating permits are required for any installation whose potential emissions of air contaminants is at or above the major source threshold. Operating permits are intended to identify all relevant requirements that apply to the various emission units at a plant, site or facility. Operating permits can establish detailed provisions for any testing, emissions monitoring, recordkeeping or reporting that is needed to demonstrate compliance with the regulations. Operating permits are not intended to be the source of new emissions limitations or requirements. Instead, operating permits are intended to identify and state all of the existing requirements that apply to the plant, site or facility; this helps the plant manager ensure compliance with these existing requirements, since they will now be explicitly identified both for the regulated source, and for the regulatory agencies themselves. Said another way, operating permits are intended to be vehicles for defining existing compliance obligations; they are not intended to impose new limits on emissions.

An operating permit expires after five years. The application to renew the operating permit must be submitted at least six months before the permit expires, though the application can be submitted as much as 18 months prior to the expiration date; once an application has been submitted and found to be complete, the “application shield” ensures that the existing operating permit will not expire in the event that the renewal permit is not issued prior to the expiration date of the existing operating permit. 

Note: This information is not meant to be a tool to determine applicable federal and state regulations for a specific situation. The method of choice should always be a thorough review of the state and federal rules and regulations. 

An Intermediate installation is a Part 70 installation that accepts voluntary, federally-enforceable limitations on production and/or emissions, type of materials combusted or processed, operating rates, or hours of operation in order to reduce the potential to emit and maintain the installation's actual emissions below major source levels. These limits may have already been taken in a construction permit or may be requested as part of the Intermediate operating permit application.

Intermediate operating permits are valid for a five year term. A permit shield provides protection for the installation if it has complied with all of the conditions in the operating permit.

Initial Applications

A complete application for an initial Intermediate operating permit must be submitted within 90 days after the installation begins operation. 

Renewal Applications

In order to renew an Intermediate operating permit, a renewal application must be submitted. In order to qualify for an application shield, a complete application to renew the permit must be submitted at least six months prior to the expiration date of the current intermediate operating permit, but no earlier than 18 months prior to the expiration date of the current intermediate operating permit.

Application Process

The application forms are available under the Forms and Applications section of our website.

All applications and applicable filing fee must be submitted by mail to the Missouri Department of Natural Resources, Air Pollution Control Program, PO Box 176, Jefferson City, MO 65102 or in person at 1659 E. Elm St., Jefferson City, Missouri. We are not currently able to accept applications submitted by email or fax. Fee amounts and payment options are detailed on the Fees tab. 

Draft initial and renewal Intermediate operating permits are required to go through a 30-day public comment period before issuance.

Missouri Revised Statutes: 643.050, RSMo

Applicable Regulations: 10 CSR 10-6.065 and 40 CFR Part 70

Note: This information is not meant to be a tool to determine applicable federal and state regulations for a specific situation. The method of choice should always be a thorough review of the state and federal rules and regulations. 

A Part 70 operating permit is required for installations that emit, or have the potential to emit, air pollutants in excess of the major source levels. An installation must also obtain a Part 70 operating permit, regardless of potential to emit, in certain other cases, described here.

Part 70 operating permits are valid for five years. A permit shield provides protection for the installation if they have complied with all of the conditions in their operating permit.

Initial Applications

A complete application for an initial Part 70 operating permit must be submitted within 12 months after the installation begins operation. 

Renewal Applications

In order to renew a Part 70 operating permit, a renewal application must be submitted. In order to qualify for an application shield, a complete application to renew the permit must be submitted at least six months before the expiration date of the current Part 70 operating permit, but no earlier than 18 months before the expiration date of the current Part 70 operating permit.

Application Process

The application forms are available under the Forms and Applications section of our website.

All applications and applicable filing fee must be submitted by mail to the Missouri Department of Natural Resources, Air Pollution Control Program, PO Box 176, Jefferson City, MO 65102 or in person at 1659 E. Elm St., Jefferson City, Missouri. We are not currently able to accept applications submitted by email or fax. Fee amounts and payment options are detailed on the Fees tab. 

Draft initial and renewal Part 70 operating permits as well as draft significant modifications to Part 70 operating permits are required to go through a 30-day public comment period and a 45-day EPA review period before issuance.

Missouri Revised Statutes: 643.050, RSMo

Applicable Regulations: 10 CSR 10-6.065 and 40 C.F.R. Part 70

Note: This information is not meant to be a tool to determine applicable federal and state regulations for a specific situation. The method of choice should always be a thorough review of the state and federal rules and regulations. 

Applications for permits and renewal permits require a filing fee. No filing fee is required for applications to amend or modify existing operating permits. 

Operating permit filing fees are determined using a tiered system based on the complexity of the permit. The total filing fee is the base fee plus the sum of all applicable complexity fee items the facility is subject to at the time the permit application is submitted. This tiered system for calculating the operating permit filing fee applies to initial and renewal applications for permits. Beginning Jan. 1, 2026, the base filing processing fees for Intermediate Operating Permits are changing. These updated fees are provided in Table 1 below. Fees applicable until Dec. 31, 2025, are available on the Air Operating Permit Fees white sheet.

Total filing fee = (Base Fee from Table 1) + (Additional Complexity Fee determined from Table 2) 

The total filing fee is the amount due upon filing an operating permit application, not to exceed $6,500, regardless of the calculated amount. Payment of the filing fee may be made by check enclosed with the application or electronically. A convenience fee will be charged to all customers who wish to pay by electronic method. 
 

Permittee Initiated Changes

There are five types of modifications that an installation can request be made to its Part 70 operating permit:

• Significant Modification
• Minor Modification
• Administrative Amendment
• Off-Permit Change
• §502(b)(10) Change

There are three types of modifications that an installation can request be made to its Intermediate operating permit:

• Intermediate Permit Modification
• Administrative Amendment
• Off-Permit Change

Regulatory Agency Initiated Changes

The department's Air Pollution Control Program or the U.S. Environmental Protection Agency (EPA) may reopen the operating permit to make certain changes. For example, an operating permit may be reopened for cause if a regulation becomes applicable to the installation and more than three years remains on the life of the permit. Another example would be if the permitting authority or EPA discovers that an applicable permit requirement has been omitted from the permit – the permit would be reopened for cause to insert the relevant applicable permit requirements.

Modification Process

No filing fee is required for applications to amend or modify existing operating permits. Draft significant modifications to Part 70 operating permits are required to go through a 30-day public notice period and a 45-day EPA review period prior to issuance. All other modifications are generally issued without public notice.

Missouri Revised Statutes: 643.050, RSMo

Applicable Regulations: 10 CSR 10-6.065 and 40 CFR Part 70

Note: This page does not provide guidance for modifications to Title 4 (Acid Rain) permits. Modifications to Acid Rain permits must be made following the permit revisions procedures in 40 C.F.R. Part 72, Subpart H. If you are revising an Acid Rain permit, please contact the department's Air Pollution Control Program, Operating Permits Unit for guidance.

How long will it take for my permit to be issued?

• Initial/ renewal Intermediate/ Part 70 operating permits: The Air Pollution Control Program is required to issue the permit within 18 months of receiving a complete application.
• Significant modifications to a Part 70 operating permit: The Air Pollution Control Program is required to issue the modified permit within 6 months of receiving a complete application.
• Minor modifications to a Part 70 operating permit: The Air Pollution Control Program is required to issue the modified permit within 90 days of receiving the application.
• Modified Intermediate operating permits: The Air Pollution Control Program is required to issue the modified permit within 9 months of receiving a complete application.
• Administrative amendments to Intermediate/ Part 70 operating permits: The Air Pollution Control Program is required to issue the modified permit within 60 days of receipt of the application.
• §502(b)(10) and off-permit changes: The Air Pollution Control Program does not issue a new/ modified operating permit. A copy of the notification should be retained with the current operating permit.

What is the status of my application?

Electronic copies of air permit applications received by the department that are currently under review can be found on the department's Pending Air Permits webpage. The list includes applications for construction permits, also called new source review permits, and operating permits.

What permits are on public notice?

Public notices that have been issued for currently open public comment periods and scheduled public meetings, public hearings and other public events for air-related issues and regulated facilities can be found on the department's Air Public Notices webpage. Each public notice listed contains links to available electronic documents pertaining to that public notice and for information about how to submit comments.

Permit Assistance, Information and Resources

• Forms and Applications
• Citizens Guide to Air Permits
• Air Pollution Compliance Regulatory Assistance
• Code of State Regulations 10 CSR 10

Additional Resources

• Air Emissions Inventory Improvement Program (EIIP) - EPA
• Air Permit Policy and Guidance Databases - EPA
• AP-42: Compilation of Air Emissions Factors from Stationary Sources - EPA
• Applicability Determination Index (ADI) - EPA
• EMC Compliance Assurance Monitoring - EPA
• State Implementation Plans (SIPs)
• WebFIRE - EPA's online database that contains emissions factors for criteria and HAP for industrial and non-industrial processes and reports submitted to EPA.