Reporting Guidance

Canola Field

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 workshop page.


FAQs SLEIS User GuidanceExternal Resources Regulated Air Pollutants

Frequently Asked Questions (FAQs)

Who must submit an Emissions Inventory?
Subchapter 5 (OAC 252:100-5) requires owners or operators of any facility that is a source of regulated air pollutants to submit an emission inventory through DEQ’s electronic reporting system or in another manner acceptable by the Division. The owners or operators of permit exempt facilities or de minimis facilities, as these terms are defined in OAC 252:100-7-1.1, are not required to submit an annual emission inventory unless annual emissions from the facility exceed any of the emission thresholds listed in Table 1 in Appendix A to Subpart A of 40 CFR Part 51.
How often should an Emissions Inventory be submitted?
An annual inventory is required every year, with the exception of facilities registered under a permit by rule (PBR). The Oklahoma Administrative Code rule regarding emission inventory reporting for PBRs is included below.

OAC 252:100-5-2.1(a)

(2) Permit by rule. The owner or operator of a facility registered under a permit by rule in Subchapter 7, Part 9, shall submit, at a minimum, an annual emission inventory for the 2014 reporting year or the calendar year in which the facility is registered, if the facility is registered after December 31, 2014, and thereafter according to the following schedule:

(A) For a registered facility with actual emissions greater than 5 tons per year of any regulated air pollutant, an annual emission inventory for that facility shall be submitted for every National Emissions Inventory (NEI) Three-Year Cycle Inventory year, as defined in 40 CFR Section 51.30(b).

(B) For a registered facility with actual emissions of 5 tons per year or less of any regulated air pollutant, an annual emission inventory for that facility shall be submitted every second National Emissions Inventory (NEI) Three-Year Cycle Inventory year, as defined in 40 CFR Section 51.30(b), beginning with the 2020 NEI reporting year.

Example: When a facility obtains registration under a PBR in 2021, the facility must submit an initial emission inventory (2021). If the facility has actual emissions greater than 5 tons per year of any regulated air pollutant in 2023 (which is an NEI Three-Year Cycle Inventory year), a 2023 emission inventory must be submitted, otherwise their next report due is a 2026 emission inventory (which would be the second NEI Three-Year Cycle Inventory year).

Note: the goal of the rule is to capture the initial inventory for the facility, so if in the example the facility didn’t begin operating until 2022 then the facility would report “Not Yet Built” for the facility operating status in 2021, and then report their initial inventory for 2022.

How do I submit an Emissions Inventory?
The Oklahoma Air Pollution Control Rules in OAC 252:100-5-2.1(a) state, “The owner or operator of any facility that is a source of regulated air pollutants shall submit a complete annual emission inventory through DEQ’s electronic reporting system or in another manner acceptable by the Division.” SLEIS (State and Local Emission Inventory System) is the current acceptable electronic reporting system.
What must be submitted? Is there a minimum threshold for reporting emissions?
Report the amount of actual emissions of all regulated air pollutants.

A lower cut-off or minimum amount of emissions of an individual pollutant that should be reported is not defined by rule. If emissions are 0.1 tons or greater of any regulated air pollutant at a process, then the emissions must be reported. The key exceptions that must be reported at 0.001 tons or greater per process are:

  1. Lead, mercury, and chromium
  2. Any Hazardous Air Pollutant (HAP) at a facility that is also reported to the Toxics Release Inventory (TRI)
  3. Any HAP from glycol dehydration still vents
  4. Any HAP from large storage tanks (>500 BBL)
  5. Other situations where deemed necessary

Grouping Emission Units

Small sources that individually do not have reportable emissions, but collectively have emissions over the reporting threshold, should be reported. They can be grouped into one source. For example, all of the small sources at one process unit or building could be submitted together. Emergency generators can often be grouped in an inventory.

  • The emission unit name should include the number of units being grouped.
  • The release point should be reported as a fugitive with the total area of all the units and the average height.
  • Process rates, including maximum hourly and typical daily, should be reported as an average.
  • Operating periods, including the actual hours per year, should be reported as an average.
  • Design capacity should be reported as an average.
  • Actual emissions should be the sum of emissions calculated based on the actual process rate or actual hours per year of the individual units, not the averaged values.
  • An emission unit note should be added to further clarify the number of units being grouped and the individual design capacities (if a combustion process).
When are inventories due?
April 1 after the year of operations, unless an extension is approved or the facility has a Permit By Rule (PBR) alternate reporting schedule.
Can a company obtain a list of facilities that must report?
The Emission Inventory Section makes every effort to track facilities’ Emissions Inventory reporting requirements; however, it is the owner/operator’s responsibility to know which facilities must report. Contact us for assistance in identifying a comprehensive list.
How can a permit be terminated?

A permit may be terminated when a facility permanently ceases operations or when either DEQ or the facility representatives determine that the facility qualifies for “permit exempt” or “de minimis” status as defined in OAC 252:100-7. A facility representative may self-determine the facility’s eligibility to claim either status and request DEQ terminate the permit. A termination request should be made in writing and address the following:

  • Provide reason for termination (closure, permit exempt, de minimis)
  • Reference the permit number
  • Provide facility and company name
  • Provide date when facility ceased operations or became eligible for “permit exempt” or “de minimis” status
  • Where the facility has ceased operations, please indicate if emitting equipment has been removed or remains in place.

Call 405-702-4100 and ask to speak with permitting staff for additional guidance.

What is SLEIS?
SLEIS (State and Local Emissions Inventory System) is a web-based reporting system purchased from Windsor Solutions and is the agency’s recommended tool for submitting annual Emissions Inventories.
What browser can I use with SLEIS?
SLEIS includes cross-browser compatibility and most common browsers will work (Chrome, Edge, Firefox).
How does a company get access to SLEIS?
The company Responsible Official (RO) must complete a Designation of Responsible Official / SLEIS Registration Form #100-882 and submit to the emissions inventory section at the DEQ. The RO will then receive an email with instructions on creating a SLEIS password. Once the password has been created, the user will be able to login to SLEIS and access their company. The company RO will be assigned the Administrator and Submitter roles. They will also be assigned either the Editor or Viewer role.
Can more than one person in our company use SLEIS or be designated as an RO?
Yes. Any individual who is authorized by the company RO (Administrator) can enter information under their own SLEIS account. All users must create a user’s account for SLEIS access. The company RO can specify authorizations for all company users i.e., User, Submitter, Editor, or Reviewer.
Does the Responsible Official (RO) have to physically sign the final submission when using SLEIS?
No. The RO does not need to physically sign the final submission when using SLEIS. Under Oklahoma Statute (12A O.S. sec. 15-101 et seq.), compliance with the conditions on the SLEIS Attestation (Agreement) page results in a legally binding electronic signature.
How can a company designate or change a Responsible Official (RO)?
Complete Designation of Responsible Official / SLEIS Registration Form #100-882 and mail or email the completed form to the address listed on the form.
How can a company designate or change a Main Facility Contact (MFC)?
Submit the MFC contact information (name, title, email, mailing address and telephone number) via email to for contacts not requiring a SLEIS account. Company or facility representatives requiring a SLEIS account should complete DEQ Form #100-733 SLEIS User Registration, and mail or email the completed form(s) to the address indicated on the form. An email link to create your initial account password will be sent.
How long must we retain records?
All supporting data, including actual production, throughput, and measurement records along with engineering calculations and other data utilized in accordance with OAC 252:100-5-2.1(d) must be maintained for at least 5 years by the current owner or operator at the facility in conjunction with facility records of the emission inventory. This information must either be submitted to the Division or made available for inspection upon request.
What if an error is discovered in our inventory?
If DEQ finds an error, a company may be required to submit corrections for inventories submitted over the past 5 years. If the company finds an error, the company need only correct the error if it occurred within the last three years. Contact our office for instructions on submitting an amendment. Amendments can be entered and submitted directly in SLEIS by the company. Log in to the SLEIS company account, select the facility and year requiring an amendment and select the “Request Amendment” selection from the right side of the screen. You will receive an email when the report is available for amending.
Reporting Requirements when converting to a Permit By Rule (PBR)
If the removal of permitted equipment causes a facility operating under an Individual or General Permit to become eligible for a Permit by Rule, the facility must still submit an emissions inventory for the year in which the equipment was removed. If the facility was eligible for a Permit By Rule the entire year (and it is not a required triennial reporting year), the facility does not need to submit an emissions inventory. The emissions inventory from the prior year will be used to satisfy the PBR reporting schedule.

Although the Emissions Inventory Section makes every effort to track facilities’ reporting requirements, contact us if you believe there is a discrepancy.

Subchapter 5 of OAC 252:100 directly governs the submission of Emissions Inventories. For any question or in any situation, the Air Quality Rules always apply.

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

Click on the blue links.

  • 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

Regulated Air Pollutants (RAPs) – This web page details all pollutants currently regulated in Oklahoma by State or Federal rule or regulation. Emissions of any of these pollutants must be reported as part of an emissions inventory, not just of pollutants that are specifically limited in a facility’s permit.