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.
What this page shows
This page covers Clean Air Act facilities in the EPA air register with stack tests in Rosebud county, MT, in 2026. It lists 16 stack tests recorded in 2026.