EPA Approves Muscatine, Iowa, Air Quality Redesignation
LENEXA, KAN. (NOV. 18, 2025) – Today, U.S. Environmental Protection Agency (EPA) has approved the State of Iowa’s request to redesignate the Muscatine Area from nonattainment to attainment for the 2010 1-Hour Sulfur Dioxide (SO2) National Ambient Air Quality Standard (NAAQS).
The Iowa Department of Natural Resources (IDNR) worked collaboratively with industry to develop strategies to reduce SO2 emissions at industrial facilities and bring the Muscatine Area into attainment with the 2010 SO2 standard. These efforts resulted in a 98% reduction in total annual SO2 emissions from 2013 to 2023. Today’s approval, following the work by the State and local businesses, reflects the EPA’s commitment to cooperative federalism, pillar three of the Powering the Great American Comeback initiative.
“This milestone achievement represents years of hard work and dedication on behalf of the Iowa Department of Natural Resources, as well as local businesses committed to improving air quality in Muscatine,” said EPA Region 7 Administrator Jim Macy. “We commend Iowa’s commitment to working alongside industry partners to reduce SO2 emissions and deliver clean air for the community of Muscatine.”
“This announcement is a tremendous win for Muscatine and a testament to what can be achieved when government, industry, and the community work together toward a common goal,” said Muscatine Mayor Brad Bark. “Our community has made great strides in improving air quality, protecting public health, and ensuring Muscatine remains a great place to live, work, and raise a family. We are proud of the collaboration that made this achievement possible.”
“Since EPA's revision to the SO2 standards in 2010, our collaborative efforts with both the community and industry have led to a remarkable reduction in SO2 concentrations—from 217 ppb to just 17 ppb,” said IDNR Director Kayla Lyon. “This achievement highlights the immense commitment and hard work put forth in planning, engineering, and installing new equipment to ensure Muscatine meets and remains below the 1-hour standard of 75 ppb.”
To redesignate a nonattainment area to attainment, the Clean Air Act (CAA) requires EPA to determine the State has met all applicable requirements for the NAAQS. EPA’s final rule details how the Muscatine Area meets the CAA requirements for redesignation, including a maintenance plan ensuring continued compliance through 2035.
For more information on the Muscatine Area final 2010 1-Hour SO2 redesignation, visit docket number EPA-R07-OAR-2025-0818 at https://www.regulations.gov/.
Learn more about how EPA works with states to reach attainment for SO2 emissions.
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