Missouri's Air Conservation Commission holds a public hearing today on a revised Regional Haze Plan after federal regulators rejected the state's 2022 proposal. The U.S. Environmental Protection Agency disapproved Missouri's initial plan in July 2024, citing insufficient pollution controls to meet federal visibility standards under the Clean Air Act.
Regional haze obscures visibility at national parks and wilderness areas across the country, primarily from sulfur dioxide and nitrogen oxide emissions produced by power plants, refineries, and industrial facilities. The EPA requires states to demonstrate "reasonable progress" in reducing these pollutants every five years under the Regional Haze Rule, first enacted in 1999 and strengthened in 2005. Missouri's failure to meet this standard triggered the federal rejection and forced the state's Department of Natural Resources to draft a replacement plan.
The public comment period extends through September 3rd. Environmental groups and air quality advocates have criticized Missouri's original proposal for failing to impose adequate emissions reductions from the state's coal-fired power plants and industrial sources. The revised draft plan must demonstrate how Missouri will reduce regional haze pollutants to achieve visibility improvements at protected areas, primarily the Ozark National Scenic Riverways and portions of the Mark Twain National Forest.
Power plants represent the largest controllable source of sulfur dioxide and nitrogen oxides in Missouri. States must evaluate whether existing emissions control equipment at these facilities can be upgraded or replaced to meet federal visibility targets. The EPA's rejection signals that Missouri's initial approach either underestimated emission levels, overestimated the effectiveness of existing controls, or failed to require adequate new pollution control technology installation.
Regional haze affects more than 156 million Americans and damages tourism and public health. Sulfur dioxide and nitrogen oxides form secondary organic aerosols and particulate matter that reduce visibility while also contributing to respiratory illness, heart disease, and premature death. Studies show that residents living near haze-affected regions experience higher rates of asthma exacerbation and emergency room visits.
Missouri's revised plan must identify specific emission reduction strategies, timelines for implementation, and monitoring protocols. The state may require Best Available Retrofit Technology (BART) installation at power plants built between 1977 and 1987, impose stricter emissions limits on industrial facilities, or mandate fuel switching to lower-sulfur alternatives. States have used all three approaches in their regional haze compliance efforts.
The hearing occurs as Congress and the Trump administration have signaled skepticism toward Clean Air Act enforcement. Missouri's compliance history remains mixed. The state has faced EPA enforcement actions on particulate matter and ozone standards in recent years, suggesting capacity challenges within DNR's air quality division.
Public participation in today's hearing and the September 3rd comment deadline represents the primary opportunity for residents and environmental organizations to influence Missouri's pollution control strategy. Comments submitted to DNR become part of the federal administrative record when Missouri resubmits the revised plan to EPA for approval, typically expected within 18 months of the federal rejection date.