EPA Air · stack tests by county and year
Air-emissions stack tests in Rosebud County, Montana, 2026
- 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 Rosebud County, Montana during 2026. 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.
Rosebud County, Montana, 2026
Air-emissions stack tests in Rosebud County, other years
Air-emissions stack tests recorded in Rosebud County, Montana, 2026
| Date | Facility | Kind | Agency |
|---|---|---|---|
| 2026-06-05 | WILLISTON BASIN - HATHAWAY STATION | Pass | State |
| 2026-06-05 | WILLISTON BASIN - HATHAWAY STATION | Pass | State |
| 2026-05-21 | COLSTRIP STEAM ELECTRIC STATION | Pass | State |
| 2026-05-21 | COLSTRIP STEAM ELECTRIC STATION | Pass | State |
| 2026-04-09 | COLSTRIP STEAM ELECTRIC STATION | Pass | State |
| 2026-04-09 | COLSTRIP STEAM ELECTRIC STATION | Pass | State |
| 2026-04-09 | COLSTRIP STEAM ELECTRIC STATION | Pass | State |
| 2026-04-09 | COLSTRIP STEAM ELECTRIC STATION | Pass | State |
| 2026-04-08 | COLSTRIP STEAM ELECTRIC STATION | Pass | State |
| 2026-04-08 | COLSTRIP STEAM ELECTRIC STATION | Pass | State |
| 2026-01-29 | COLSTRIP STEAM ELECTRIC STATION | Pass | State |
| 2026-01-13 | COLSTRIP ENERGY LTD PARTNERSHIP | Pass | State |
| 2026-01-13 | COLSTRIP ENERGY LTD PARTNERSHIP | Pass | State |
| 2026-01-13 | COLSTRIP ENERGY LTD PARTNERSHIP | Pass | State |
| 2026-01-07 | WILLISTON BASIN - HATHAWAY STATION | Pass | State |
| 2026-01-07 | WILLISTON BASIN - HATHAWAY STATION | Pass | State |
Dates as filed by the agency that recorded the stack test. Figures from EPA’s ICIS-AIR download.