CEDAR FALLS, Iowa - Time for Iowa businesses that operate in Central Iowa and all portable plants to submit the Minor Source Emissions Inventory (MSEI) by May 15, 2026. 

Who needs to file?

• Iowa businesses notified by the Iowa DNR and operating as minor sources in the following counties: Appanoose, Boone, Butler, Cerro Gordo, Clarke, Dallas, Decatur, Floyd, Franklin, Grundy, Hamilton, Hancock, Hardin, Humboldt, Jasper, Kossuth, Lucas, Madison, Mahaska, Marion, Marshall, Mitchell, Monroe, Polk, Poweshiek, Story, Tama, Warren, Wayne, Webster, Winnebago, Worth and Wright.
• All portable plants notified by the DNR and operating in Iowa

Free training & tools for small businesses

The Iowa Air Emissions Assistance Program (IAEAP) at the Iowa Waste Reduction Center (IWRC) offers free one-on-one training for small businesses (under 100 employees) to help complete the MSEI accurately and on time. 

Support includes: 

• Personalized one-on-one training and assistance from an IAEAP specialist
• Review of emission calculations
• Guidance on data entry and submittal of inventories using the State and Local Emissions Inventory System (SLEIS)
• Access to updated emissions calculators and tutorials

"Jennifer W. was absolutely wonderful to work with! A true asset to IAEAP! I can tell that she cares deeply about her job and helping people with Minor Emission Inventory. She made the process easier than I could have ever imagined.” – 2025 Client

“Jordan was tremendous.  Extremely responsive and timely, and when it came time to fill out the submission she was prepared, patient, and efficient.  A great use of my time!” – 2025 Client

How to get help

Visit iwrc.uni.edu/msei to:

• Request free one-on-one training or assistance
• Access industry and process specific calculators
• View tutorials and other MSEI resources

Key dates & submission information

• Deadline: May 15, 2026  
• Submission methods: Electronically through SLEIS or specialized spreadsheets and forms approved by the DNR. 

What is the MSEI data used for?

The Minor Source Emissions Inventory is a required report that helps the DNR:

• Track Iowa’s progress towards meeting national air quality standards
• Perform regional and local air dispersion modeling
• Develop control and maintenance strategies required by the Clean Air Act
• Identify emissions trends statewide

Contact

For questions

Jennifer Wittenburg, IAEAP Program Manager, IWRC
319-273-6580
jennifer.wittenburg@uni.edu 

For media inquiries

Molly Wells, Communications & PR Manager, IWRC
319-273-4307
molly.wells@uni.edu

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About IWRC. The Iowa Waste Reduction Center at the University of Northern Iowa has provided environmental services, technical assistance, and training to Iowa businesses for over 30 years. Learn more at iwrc.uni.edu.