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.