MPCA Air Toxics Rulemaking Moves Forward After Two-Day Administrative Hearing
The Minnesota Pollution Control Agency (MPCA) held a two-part administrative hearing on its proposed air toxics rules on Monday and Tuesday, October 5 and 6, 2026. The public now has an additional chance to provide written comment before Administrative Law Judge James Mortenson issues his report on the propriety of the proposed rules.
Background
The Minnesota Legislature, in 2023, passed two pieces of legislation regarding air toxics emissions. The first, codified at Minn. Stat. § 116.062, addresses how owners and operators of facilities with an air quality permit in the seven counties surrounding Minneapolis and St. Paul must report their facilities’ annual air toxics emissions. On October 6, 2025, the MPCA commissioner published the final version of rules governing the toxics emissions reporting process.
The second piece of 2023 legislation, Minnesota Session Law - 2023, Chapter 60, article 8, section 5 (H.F. No. 2310), directs the MPCA commissioner to adopt rules regulating air toxic emissions themselves. The Legislature mandated that the rules, at a minimum, specify the air toxics to be regulated, acceptable tests for measuring the air toxics emissions, and the types of facilities subject to the requirements, i.e., those with air quality permits (with certain exceptions) in the seven-county metro area.
The MPCA commissioner published a draft of this second set of air toxics rules in the Minnesota State Register on May 18, 2026. The proposed rules incorporate air toxic emission considerations into existing rules governing air permits in Minn. R. Ch. 7007. More importantly, they create a new regulatory chapter — 7012 — devoted exclusively to the regulation of air toxic emissions. The proposed rules would impose substantial new analytical and compliance obligations on many permitted facilities and mark a significant expansion of Minnesota’s air toxics regulatory framework. More specifically, the proposed rules will require affected facilities to compare calculated air toxics emissions against screening thresholds for each air toxic. Those above one or more screening thresholds must either implement a Compliance Determination Protocol (CDP) to stay below the screening threshold(s) or complete an Air Emissions Risk Analysis (AERA), if they believe modeling will show their emissions to be below the applicable threshold(s). Failure to model compliance through an AERA will require a facility owner or operator to submit a CDP or complete and submit an Air Toxics Reduction Plan (ATRP) and make relevant notifications to potentially impacted residents. The MPCA views this informally as a three-stage process, as shown in the slide below:
Slide author: Minnesota Pollution Control Agency
Sixteen parties submitted comments during the initial public comment period, which ended on July 17, 2026. The MPCA published responses to those comments as part of the exhibits it offered at the administrative hearing. The responses included a series of changes to the draft rules published in May, none of which the MPCA deemed to be “substantially different” enough to warrant re-noticing for public comment. While many were changes to definitions, others involved more substantive changes, such as clarifying compliance deadlines and revision requirements for CDPs and clarifying certain aspects of the ATRP report.
Administrative Hearing
During the two hearings, only one person offered oral comments on the proposed rules. This individual suggested that environmental justice areas within the draft rules should be based on census tracts, not census blocks, and that facilities that emit certain toxics, such as lead, be forced to be closed after a period of time, even if below screening thresholds, due to the cumulative effects of those pollutants.
Next Steps
Judge Mortenson, at the start of the October 5th hearing, used his statutory authority to reopen public comment following the conclusion of the two-day hearing. Post-hearing comments must be received by 4:30 p.m. on Tuesday, November 3, 2026. A five-business-day period will then commence to allow the public to provide rebuttal comments to those submitted before November 3rd. Those rebuttal comments must be submitted by 4:30 p.m. on Tuesday, November 10, 2026. Judge Mortenson intends to issue his report on the validity of the rules within 30 days of the submission of the last comments, unless an extension to that deadline is ordered. Those who wish to submit post-hearing or rebuttal comments are encouraged to do so electronically at the OAH’s website (Docket # 5-9003-39347) but may also mail comments to Court of Administrative Hearings, Attn: William Moore, P.O. Box 64620, St. Paul, MN 55164-0310 or fax them to 651-539-0310 by the above deadlines. Mailed or faxed comments must reference “PCA Air Toxics Rules” and the docket number to ensure proper filing.
Stay tuned to this blog for future developments on these rules and their implementation, and please reach out to me if I may be of any assistance with any of your environmental law needs.