EPA Air · stack tests by county and year
Air-emissions stack tests in Big Horn County, Montana, 2021
- 8Stack 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 Big Horn County, Montana during 2021. 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 Big Horn County facility page.
Air-emissions stack tests in Big Horn County, other years
Air-emissions stack tests recorded in Big Horn County, Montana, 2021
| Date | Facility | Kind | Agency |
|---|---|---|---|
| 2021-10-08 | ROCKY MOUNTAIN POWER | Pass | State |
| 2021-10-08 | ROCKY MOUNTAIN POWER | Pass | State |
| 2021-10-08 | ROCKY MOUNTAIN POWER | Pass | State |
| 2021-07-22 | ROCKY MOUNTAIN POWER | Pass | State |
| 2021-07-01 | ROCKY MOUNTAIN POWER | Pass | State |
| 2021-04-19 | ROCKY MOUNTAIN POWER | Pass | State |
| 2021-01-21 | ROCKY MOUNTAIN POWER | Pass | State |
| 2021-01-12 | ROCKY MOUNTAIN POWER | Pass | State |
Dates as filed by the agency that recorded the stack test. Figures from EPA’s ICIS-AIR download.