See the latest EHS federal and state regulatory updates due to COVID-19


The latest Montana Clean Air Act Advisory Committee (CAAAC) meeting was held on February 7, 2019. The main CAAAC meeting topics included a portable source registration program and a regional haze update.

Portable Registration Program

The Montana Department of Environmental Quality (MDEQ) Air Quality Bureau has proposed a Portable Registration Program for portable plants (e.g. asphalt plants and concrete batch plants) in lieu of issuing Montana Air Quality Permits (MAQPs) for these source types. MDEQ is expecting to request rule adoption by the Board of Environmental Review (BER) on April 12, 2019. If the BER adopts the rule, which is expected, the registration process should be available by late-Spring 2019. Existing MAQP portable facilities will be required to transition to the Registration Program by the end of 2019. The fees for 2019 will remain the same, but Fall 2020 fees are expected to be based on 2019 production values, so it will be important for facilities to collect accurate 2019 production data.

Regional Haze Program Update

MDEQ is working toward developing a State Implementation Plan (SIP) for the second implementation period of the regional haze program, which is due to Environmental Protection Agency (EPA) by July 31, 2021.

The 2017 revised regional haze rule focuses on 20% “most-impaired days” instead of 20% “haziest days” as evaluated in the original regional haze rule. Switching to evaluating the “most-impaired days” reduces the influence of extreme episodic events, which for Montana Class I areas tends to be from wildfire smoke. Visibility impacts from SO2 and NOx are more apparent with the revised methodology and will be Montana's focus for emission reductions.

MDEQ is in the process of analyzing visibility data and beginning to screen permitted stationary sources for further analysis. The screening process will use the sum of a source's NOx and SO2 emissions (Q) and ratio by their distance to the nearest Class I area (d) to identify a “Q/d” ratio for each stationary source. MDEQ will then rank each source by its “Q/d” ratio, and determine which sources “screen out” of further analysis and which sources should conduct a four-factor analysis and evaluate emission reduction strategies.

In the near future, MDEQ is expecting to kick-off conversations with sources regarding the four-factor analysis and analyzing projected 2028 emissions and modeling results. A four-factor analysis will include, cost of compliance, time necessary for compliance, energy and non-air quality environmental impacts of compliance, and remaining useful life of any potentially affected major or minor stationary source.

For more assistance or more information on the portable registration program or Montana's regional haze updates contact Ashley Jones at (720) 638-7647 ext. 103. The CAAAC meeting slides can be found on MDEQ's website.