An official website of the United States government.

This is not the current EPA website. To navigate to the current EPA website, please go to This website is historical material reflecting the EPA website as it existed on January 19, 2021. This website is no longer updated and links to external websites and some internal pages may not work. More information »

Sulfur Dioxide Designations

Sulfur Dioxide (SO2) Designations Round 3: South Dakota State Recommendation and EPA Response

Read the South Dakota recommendation for Round 3 area designations and EPA's response.