EPA Air · stack tests by county and year
Air-emissions stack tests in Williamson County, Illinois, 2025
- 16Stack tests
A stack test measures what a source actually emits, at the stack, against the limit in its permit. Each row below is one stack test recorded against a source in Williamson County, Illinois during 2025. A facility can appear several times: this is the year’s record of what happened, not a list of places. The sources themselves are on the Williamson County facility page.
Williamson County, Illinois, 2025
Air-emissions stack tests in Williamson County, other years
Air-emissions stack tests recorded in Williamson County, Illinois, 2025
| Date | Facility | Kind | Agency |
|---|---|---|---|
| 2025-11-19 | SOUTHERN ILLINOIS POWER COOP | Pass | State |
| 2025-07-16 | WILLIAMSON ENERGY LLC | Pass | State |
| 2025-07-16 | WILLIAMSON ENERGY LLC | Pending | State |
| 2025-07-16 | WILLIAMSON ENERGY LLC | Pass | State |
| 2025-07-16 | WILLIAMSON ENERGY LLC | Pass | State |
| 2025-07-16 | WILLIAMSON ENERGY LLC | Pass | State |
| 2025-07-16 | WILLIAMSON ENERGY LLC | Pass | State |
| 2025-07-16 | WILLIAMSON ENERGY LLC | Pass | State |
| 2025-07-16 | WILLIAMSON ENERGY LLC | Pass | State |
| 2025-07-16 | WILLIAMSON ENERGY LLC | Pass | State |
| 2025-07-16 | WILLIAMSON ENERGY LLC | Pass | State |
| 2025-07-16 | WILLIAMSON ENERGY LLC | Pass | State |
| 2025-07-16 | WILLIAMSON ENERGY LLC | Pass | State |
| 2025-07-16 | WILLIAMSON ENERGY LLC | Pass | State |
| 2025-07-16 | WILLIAMSON ENERGY LLC | Pass | State |
| 2025-03-25 | SOUTHERN ILLINOIS POWER COOP | Pass | State |
Dates as filed by the agency that recorded the stack test. Figures from EPA’s ICIS-AIR download.
What this page shows
This page covers Clean Air Act facilities in the EPA air register with stack tests in Williamson county, IL, for 2025. It lists 16 stack tests recorded in 2025.