EPA Air · stack tests by county and year
Air-emissions stack tests in Rosebud County, Montana, 2025
- 20Stack 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 Rosebud County, Montana 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 Rosebud County facility page.
Air-emissions stack tests in Rosebud County, other years
Air-emissions stack tests recorded in Rosebud County, Montana, 2025
| Date | Facility | Kind | Agency |
|---|---|---|---|
| 2025-12-24 | COLSTRIP STEAM ELECTRIC STATION | Pass | State |
| 2025-12-24 | COLSTRIP STEAM ELECTRIC STATION | Pass | State |
| 2025-10-24 | COLSTRIP STEAM ELECTRIC STATION | Pass | State |
| 2025-10-16 | COLSTRIP STEAM ELECTRIC STATION | Pass | State |
| 2025-10-16 | COLSTRIP STEAM ELECTRIC STATION | Pass | State |
| 2025-08-07 | COLSTRIP STEAM ELECTRIC STATION | Pass | State |
| 2025-08-07 | COLSTRIP STEAM ELECTRIC STATION | Pass | State |
| 2025-07-21 | WILLISTON BASIN - HATHAWAY STATION | Pass | State |
| 2025-05-20 | COLSTRIP STEAM ELECTRIC STATION | Pass | State |
| 2025-05-20 | COLSTRIP STEAM ELECTRIC STATION | Pass | State |
| 2025-05-14 | WILLISTON BASIN - HATHAWAY STATION | Pass | State |
| 2025-05-02 | COLSTRIP STEAM ELECTRIC STATION | Pass | State |
| 2025-04-29 | COLSTRIP STEAM ELECTRIC STATION | Pass | State |
| 2025-04-29 | COLSTRIP STEAM ELECTRIC STATION | Pass | State |
| 2025-04-29 | COLSTRIP STEAM ELECTRIC STATION | Pass | State |
| 2025-04-29 | COLSTRIP STEAM ELECTRIC STATION | Pass | State |
| 2025-04-10 | COLSTRIP STEAM ELECTRIC STATION | Pass | State |
| 2025-04-10 | COLSTRIP STEAM ELECTRIC STATION | Pass | State |
| 2025-04-07 | COLSTRIP STEAM ELECTRIC STATION | Pass | State |
| 2025-04-07 | COLSTRIP STEAM ELECTRIC STATION | Pass | State |
Dates as filed by the agency that recorded the stack test. Figures from EPA’s ICIS-AIR download.