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Air Quality

Reporting Guidance

Instructions, References and Help for Completing an Oklahoma Air Emissions Inventory. If you need further help or have a question that cannot be answered by the information available here, then please contact the Emissions Inventory Section.

SLEIS (State and Local Emission Inventory System) training webinar recordings and presentations are available on our Training Page.

The following are guidance documents for the SLEIS online reporting tool. Additional information will be available inside SLEIS.

SLEIS System Guidance

Industry-Specific Guidance

  • AP-42 – AP-42 refers to the EPA’s Compilation of Air Pollutant Emission Factors, a series of representative values that attempt to relate the quantity of a pollutant released to the atmosphere from a particular activity.
  • CHIEF – EPA’s Clearinghouse for Inventories & Emissions Factors (CHIEF) is an excellent resource for all aspects of emissions inventories.
  • WebFIRE – WebFire is EPA’s online emissions factor repository, retrieval, and development tool. The WebFIRE database contains EPA’s recommended emissions factors for criteria and hazardous air pollutants (HAP) for industrial and non-industrial processes.
  • Source Classification Codes (SCCs) – Searchable database to find which SCC represents an emissions process or activity. EPA uses SCCs in databases such as WebFIRE and the National Emissions Inventory (NEI).
  • NAICS – This page includes a searchable list for North American Industrial Classification System (NAICS) codes for business establishments. This official U.S. Government Web site provides the latest information on plans for NAICS revisions, as well as access to various NAICS reference files and tools.
  • SIC – Use this page to determine a Standard Industrial Classification code for a facility

All facilities that are sources of air pollution, regardless of whether the source is currently permitted or an emission inventory has been submitted, are required to pay annual operating fees. Exceptions include permit exempt and de minimis facilities. Additional information on fees can be found in OAC 252:100-5-2.2.

Fee Calculations

Fees are based on annual emissions of regulated air pollutants (RAPs).

  • PM-10 is billed; PM-2.5 is not billed.
  • Total VOC is split into HAP and non-HAP VOC for billing.
  • CO is not billed.
  • Fees are calculated two years in arrears.
  • When calculating annual operating fees for facilities that are registered under Permit by Rule (PBR), the last reported inventory emission amounts are used.

Invoice

  • Invoices are sent annually to companies with 5+ tons of billable emissions on the first business day in July.
  • Facilities that cease operations are still responsible for payment of operating fees based on emissions reported when in operation.
  • New owners of facilities assume payment liability for the operating fees which can be based on emissions reported in the years of operation prior to transfer of ownership.
  • Inventory amendments with a 5+ ton increase in billable emissions may result in an adjusted invoice. Processing is done annually, separate from the annual July invoice.
  • When sources are invoiced, whether from an initial inventory or amended inventory, the fees will be assessed at the most current year rate at submission.

Fee Determination

Title V (Part 70) source fees were set at $32.30 per ton of regulated air pollutant in 2008. The fee is adjusted each year based on the change in the annual Consumer Price Index (CPI) at the end of August relative to the 2007 CPI.

New: Minor source fees were set at $36.50 per ton of regulated air pollutant as of July 1, 2024. The fee is adjusted each year based on the change in the annual Consumer Price Index (CPI) at the end of August relative to the 2024 CPI.

  • The 2025 minor source fee was $36.50 per ton; the 2026 minor source fee will be $37.56.
  • The 2025 Title V fee was $48.90 per ton; the 2026 Title V fee will be $50.33.

Additional information on fee calculations can be found in OAC 252:100-5-2.2.

Last Modified on Oct 29, 2025
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