Facilities located in the central third of Iowa and all portable plants must submit their 2025 Minor Source Emissions Inventory (MSEI) by May 15, 2026. Below is a list of Central Iowa counties included in the 2025 Minor Source Emissions Inventory:
In north-central Iowa, DNR Field Office 2 region: Butler, Cerro Gordo, Floyd, Franklin, Grundy, Hamilton, Hancock, Hardin, Humboldt, Kossuth, Mitchell, Webster, Winnebago, Worth, and Wright.
In south-central Iowa, DNR Field Office 5 region: Appanoose, Boone, Clarke, Dallas, Decatur, Jasper, Lucas, Madison, Mahaska, Marion, Marshall, Monroe, Polk, Poweshiek, Story, Tama, Warren, and Wayne.
If you have already submitted your inventory, thank you!
Filing Information
Starting January 1, 2023, the MSEI is required to be submitted using the State and Local Emissions Inventory System (SLEIS). The only exception is for group 2 grain elevators, concrete batch plants, crushing plants, and hot mix asphalt plants that use specialized forms or standardized online spreadsheets for emissions reporting. These forms and spreadsheets may continue to be used. The DNR offers several resources to assist facilities with emission inventories:
- SLEIS - Online emissions reporting tool: https://programs.iowadnr.gov/sleis
- Instructions, exemptions, FAQs, and tips to complete the inventory: Minor Source Emissions Inventory | Department of Natural Resources
- Emissions estimate tools (including spreadsheets for many processes): Emission Tools & Calculators | Department of Natural Resources
- Facilities with less than 100 employees may also contact the Iowa Air Emissions Assistance Program (IAEAP) at the University of Northern Iowa for free training and assistance. For more information, please visit https://iwrc.uni.edu/msei
DNR Staff Assistance
For questions related to the emissions inventory, please contact:
- Seth Anderson - (515) 782-3532 or Seth.Anderson@dnr.iowa.gov
- Krysti Mostert - (515) 587-8996 or Krysti.Mostert@dnr.iowa.gov
- Nick Page - (515) 725-9544 or Nick.Page@dnr.iowa.gov