On October 6, 2025, the Minnesota Pollution Control Agency (MPCA) adopted new rules regarding air toxics emissions reporting for air permitted facilities within the seven-county metro area (Anoka, Carver, Dakota, Hennepin, Ramsey, Scott, and Washington). All air permitted facilities, with the exception of those under an Option B registration permit, in the seven-country metro will be required to report air toxics emissions in the reporting year (RY) 2026 Air Emissions Inventory, due April 1, 2027.
What are air toxics?
According to the final rule, air toxics are defined as “pollutants, except for criteria pollutants, that are known or suspects to cause cancer or other serious health effects or adverse environmental and ecological effects.” According to Minnesota Rule (Minn. R.) 7019.3110 Subpart 2, the specific air toxics include the list of federal hazardous air pollutants (HAPs), per- and polyfluoroalkyl substances (PFAS) that are identified on the toxics release inventory (TRI) list provided by the U.S. Environmental Protection Agency (EPA), and additional PFAS and chemicals provided in §7019.3110 Subp. 2.
What do I need to report?
For the majority of facilities, reporting air toxics will involve the same process as reporting criteria pollutants. A facility can either use continuous emission monitor data, performance test data, material balance, emission factors, or enforceable limitations to calculate reported emissions. For air permittees with an Option C Registration permit, in addition to the information that was already required to be provided (such as fuel purchases, fuel usage, and quantity and density of VOC-containing materials purchased or used) air permittees must also now report the weight factor of air toxics in the VOC-containing materials and the density of the material.
In an email sent out to permit holders on December 16, 2025, the MPCA explained that for air permittees with a Registration Permit Option D, Option D Hot Mix, or Nonmetallic General Permit, the MPCA will directly calculate air toxics for fuel-burning activities based on reported fuel use. If a facility with a Registration Permit Option D chooses to determine air toxics emissions separately, the facility must keep records of emissions and calculations. Similar to Option C permit holders, any calculations relying on material balance will require a review of composition data for any materials.
How to Prepare for Reporting in 2027
During 2026, it is important to start preparing for the air emission inventory submittal in 2027. This may include obtaining up-to-date safety data sheets (SDS) to have an accurate understanding of the chemical components that may need to be reported and tracking throughputs of all materials at the facility. De minimis standards provided in Minn. R. 7019.3110 Subp. 3 should be reviewed prior to reporting a chemical. Minn. R. 7019.3110 Subp. 3 does provide a few exceptions for facilities that use mass balance to calculate emissions. If, based on an SDS, an air toxic chemical is in a concentration in a mixture that is below one percent of the mixture, or is 0.1 percent of the mixture in the case of an air toxics chemical that is a carcinogen or potential carcinogen, a facility is not required to consider the quantity of the toxics chemical present in that mixture when calculating and reporting emissions. Minn. R. 7019.3110 Subp. 3 provides sources to determine whether an air toxic chemical is a carcinogen. It should be noted that certain air toxics must be reported, regardless of whether they are below the de minimis standard; these mandatory chemicals are listed under §7019.3110 Subp. 3.B.
A facility may want to update its emission tracking spreadsheet with template calculations provided by the MPCA. Using the same calculation methodologies as the agency will ensure a smoother process of validating an emission inventory. This can be especially helpful for facilities with Option C or D Registration Permits, since the MPCA plans to automatically calculate emissions using fuel usage data. Facilities can ensure that the calculations that are being done with the MPCA’s reporting portal are correct by comparing the values in the emission inventory with the values using the template calculations.
The parameters a facility is already tracking to calculate criteria pollutants emissions are likely the same parameters that will be used to calculate air toxics emissions. However, beyond operating parameters, facilities will need to determine appropriate air emission factors, which could come from performance testing, manufacturer data, or other acceptable references.
The new rules also allow for a reduction in air toxics emissions due to recycling or disposing of material off-site. In this situation, facilities must keep records of the amount of disposed material, the amount of material shipped off-site for recycling, and calculations to determine how much of a reduction can be taken. These records can include SDS, invoices, shipping papers, and hazardous waste manifests.
If your facility is in the seven-country metro area, you need to start tracking your air toxics emissions in 2026. If you would like to discuss how to prepare for next year’s air emissions inventory, please email John Ke in Trinity’s Minneapolis office or call 651.275.9900.
If you would like to discuss these new modeling thresholds for Idaho and how they may impact your facility, please contact Trinity’s Boise office or call 208.472.8837.
For more information or for assistance, please contact Trinity Consultants at 800.229.6655.
