EPA Air · stack tests by year
Air-emissions stack tests in 2026
- 11,110Stack tests
A stack test measures what a source actually emits, at the stack, against the limit in its permit.
States, 2026
- Ohio 1,474
- Indiana 1,010
- California 979
- Florida 795
- Wyoming 755
- New Mexico 724
- Georgia 509
- Pennsylvania 501
- Arkansas 374
- Alabama 357
- Missouri 326
- Texas 316
- Mississippi 263
- Michigan 207
- North Carolina 188
- Colorado 185
- Iowa 167
- Illinois 165
- South Carolina 135
- Wisconsin 135
- West Virginia 114
- Virginia 98
- Idaho 96
- Montana 91
- Tennessee 84
- Minnesota 84
- Delaware 73
- Kentucky 71
- Arizona 71
- Connecticut 68
- Kansas 63
- Nevada 57
- Massachusetts 54
- North Dakota 52
- Nebraska 51
- Utah 51
- Washington 46
- Alaska 45
- New York 43
- South Dakota 34
- District of Columbia 30
- New Hampshire 29
- Maryland 28
- Oregon 27
- Louisiana 26
- Hawaii 21
- Oklahoma 15
- Rhode Island 13
- Puerto Rico 5
- Maine 5
Other years
Air-emissions stack tests recorded in 2026
| Date | Facility | Where | Kind | Agency |
|---|---|---|---|---|
| 2026-03-12 | MARKWEST HARRISON WEST COMPRESSOR STATION | FREEPORT, Harrison, OH | Pass | State |
| 2026-03-12 | MARKWEST HARRISON WEST COMPRESSOR STATION | FREEPORT, Harrison, OH | Pass | State |
| 2026-03-12 | MARKWEST HARRISON WEST COMPRESSOR STATION | FREEPORT, Harrison, OH | Pass | State |
| 2026-03-12 | MARKWEST HARRISON WEST COMPRESSOR STATION | FREEPORT, Harrison, OH | Pass | State |
| 2026-03-12 | MARKWEST HARRISON WEST COMPRESSOR STATION | FREEPORT, Harrison, OH | Pass | State |
| 2026-03-12 | MARKWEST HARRISON WEST COMPRESSOR STATION | FREEPORT, Harrison, OH | Pass | State |
| 2026-03-12 | MARKWEST LAKE COMPRESSOR STATION | FREEPORT, Harrison, OH | Pass | State |
| 2026-03-12 | MARKWEST LAKE COMPRESSOR STATION | FREEPORT, Harrison, OH | Pass | State |
| 2026-03-12 | MARKWEST LAKE COMPRESSOR STATION | FREEPORT, Harrison, OH | Pass | State |
| 2026-03-12 | MARKWEST LAKE COMPRESSOR STATION | FREEPORT, Harrison, OH | Pass | State |
| 2026-03-12 | MARKWEST LAKE COMPRESSOR STATION | FREEPORT, Harrison, OH | Pass | State |
| 2026-03-12 | MARKWEST LAKE COMPRESSOR STATION | FREEPORT, Harrison, OH | Pass | State |
| 2026-03-12 | MARKWEST LAKE COMPRESSOR STATION | FREEPORT, Harrison, OH | Pass | State |
| 2026-03-12 | MARKWEST LAKE COMPRESSOR STATION | FREEPORT, Harrison, OH | Pass | State |
| 2026-03-12 | MARKWEST LAKE COMPRESSOR STATION | FREEPORT, Harrison, OH | Pass | State |
| 2026-03-12 | MARKWEST LAKE COMPRESSOR STATION | FREEPORT, Harrison, OH | Pass | State |
| 2026-03-12 | MARKWEST LAKE COMPRESSOR STATION | FREEPORT, Harrison, OH | Pass | State |
| 2026-03-12 | MARKWEST LAKE COMPRESSOR STATION | FREEPORT, Harrison, OH | Pass | State |
| 2026-03-12 | MARKWEST LAKE COMPRESSOR STATION | FREEPORT, Harrison, OH | Pass | State |
| 2026-03-12 | MARKWEST LAKE COMPRESSOR STATION | FREEPORT, Harrison, OH | Pass | State |
| 2026-03-12 | MARKWEST LAKE COMPRESSOR STATION | FREEPORT, Harrison, OH | Pass | State |
| 2026-03-12 | UTICA GAS SERVICES, LLC - SCIO COMPRESSOR STATION | SCIO, Harrison, OH | Pass | State |
| 2026-03-12 | UTICA GAS SERVICES, LLC - SCIO COMPRESSOR STATION | SCIO, Harrison, OH | Pass | State |
| 2026-03-12 | UTICA GAS SERVICES, LLC - SCIO COMPRESSOR STATION | SCIO, Harrison, OH | Pass | State |
| 2026-03-12 | UTICA GAS SERVICES, LLC - SCIO COMPRESSOR STATION | SCIO, Harrison, OH | Pass | State |
| 2026-03-12 | UTICA GAS SERVICES, LLC - SCIO COMPRESSOR STATION | SCIO, Harrison, OH | Pass | State |
| 2026-03-12 | UTICA GAS SERVICES, LLC - SCIO COMPRESSOR STATION | SCIO, Harrison, OH | Pass | State |
| 2026-03-12 | UTICA GAS SERVICES, LLC - SCIO COMPRESSOR STATION | SCIO, Harrison, OH | Pass | State |
| 2026-03-12 | UTICA GAS SERVICES, LLC - SCIO COMPRESSOR STATION | SCIO, Harrison, OH | Pass | State |
| 2026-03-12 | UTICA GAS SERVICES, LLC - SCIO COMPRESSOR STATION | SCIO, Harrison, OH | Pass | State |
| 2026-03-12 | UTICA GAS SERVICES, LLC - SCIO COMPRESSOR STATION | SCIO, Harrison, OH | Pass | State |
| 2026-03-12 | UTICA GAS SERVICES, LLC - SCIO COMPRESSOR STATION | SCIO, Harrison, OH | Pass | State |
| 2026-03-12 | UTICA GAS SERVICES, LLC - SCIO COMPRESSOR STATION | SCIO, Harrison, OH | Pass | State |
| 2026-03-12 | UTICA GAS SERVICES, LLC - SCIO COMPRESSOR STATION | SCIO, Harrison, OH | Pass | State |
| 2026-03-12 | UTICA GAS SERVICES, LLC - SCIO COMPRESSOR STATION | SCIO, Harrison, OH | Pass | State |
| 2026-03-12 | UTICA GAS SERVICES, LLC - SCIO COMPRESSOR STATION | SCIO, Harrison, OH | Pass | State |
| 2026-03-12 | UTICA GAS SERVICES, LLC - SCIO COMPRESSOR STATION | SCIO, Harrison, OH | Pass | State |
| 2026-03-12 | UTICA GAS SERVICES, LLC - SCIO COMPRESSOR STATION | SCIO, Harrison, OH | Pass | State |
| 2026-03-12 | UTICA GAS SERVICES, LLC - SCIO COMPRESSOR STATION | SCIO, Harrison, OH | Pass | State |
| 2026-03-12 | UTICA GAS SERVICES, LLC - SCIO COMPRESSOR STATION | SCIO, Harrison, OH | Pass | State |
| 2026-03-12 | UTICA GAS SERVICES, LLC - SCIO COMPRESSOR STATION | SCIO, Harrison, OH | Pass | State |
| 2026-03-12 | UTICA GAS SERVICES, LLC - SCIO COMPRESSOR STATION | SCIO, Harrison, OH | Pass | State |
| 2026-03-12 | UTICA GAS SERVICES, LLC - SCIO COMPRESSOR STATION | SCIO, Harrison, OH | Pass | State |
| 2026-03-12 | UTICA GAS SERVICES, LLC - SCIO COMPRESSOR STATION | SCIO, Harrison, OH | Pass | State |
| 2026-03-12 | UTICA GAS SERVICES, LLC - SCIO COMPRESSOR STATION | SCIO, Harrison, OH | Pass | State |
| 2026-03-12 | UTICA GAS SERVICES, LLC - SCIO COMPRESSOR STATION | SCIO, Harrison, OH | Pass | State |
| 2026-03-12 | UTICA GAS SERVICES, LLC - SCIO COMPRESSOR STATION | SCIO, Harrison, OH | Pass | State |
| 2026-03-12 | UTICA GAS SERVICES, LLC - SCIO COMPRESSOR STATION | SCIO, Harrison, OH | Pass | State |
| 2026-03-12 | UTICA GAS SERVICES, LLC - SCIO COMPRESSOR STATION | SCIO, Harrison, OH | Pass | State |
| 2026-03-12 | UTICA GAS SERVICES, LLC - SCIO COMPRESSOR STATION | SCIO, Harrison, OH | Pass | State |
| 2026-03-12 | UTICA GAS SERVICES, LLC - SCIO COMPRESSOR STATION | SCIO, Harrison, OH | Pass | State |
| 2026-03-12 | UTICA GAS SERVICES, LLC - SCIO COMPRESSOR STATION | SCIO, Harrison, OH | Pass | State |
| 2026-03-12 | UTICA GAS SERVICES, LLC - SCIO COMPRESSOR STATION | SCIO, Harrison, OH | Pass | State |
| 2026-03-12 | UTICA GAS SERVICES, LLC - SCIO COMPRESSOR STATION | SCIO, Harrison, OH | Pass | State |
| 2026-03-12 | UTICA GAS SERVICES, LLC - SCIO COMPRESSOR STATION | SCIO, Harrison, OH | Pass | State |
| 2026-03-12 | UTICA GAS SERVICES, LLC - SCIO COMPRESSOR STATION | SCIO, Harrison, OH | Pass | State |
| 2026-03-12 | UTICA GAS SERVICES, LLC - SCIO COMPRESSOR STATION | SCIO, Harrison, OH | Pass | State |
| 2026-03-12 | SUPERIOR MIDSTREAM LLC / REEDING COMPRESSOR STATION | CASHION, Kingfisher, OK | Pass | State |
| 2026-03-12 | COLUMBIA GAS TRANS CORP/GREENCASTLE | GREENCASTLE, Franklin, PA | Pass | State |
| 2026-03-12 | MARKWEST LIBERTY BLUESTONE LLC/BLUESTONE GAS PROC PLT | EVANS CITY, Butler, PA | Pass | State |
| 2026-03-12 | WILLIAMS FIELD SVC CO LLC/SHIELDS COMP STA | SPRINGVILLE, Susquehanna, PA | Pass | State |
| 2026-03-12 | VULCAN METALS CORP | TACOMA, Pierce, WA | Pass | Local |
| 2026-03-12 | MARKWEST LIBERTY MIDSTREAM & RESOURCES, L.L.C., MAJORSVILLE | DALLAS, Marshall, WV | Pass | State |
| 2026-03-12 | PINEDALE COMPLEX (HARVEST MIDSTREAM COMPANY) | SUBLETTE COUNTY, Sublette, WY | Pass | State |
| 2026-03-12 | PINEDALE COMPLEX (HARVEST MIDSTREAM COMPANY) | SUBLETTE COUNTY, Sublette, WY | Pass | State |
| 2026-03-12 | PINEDALE COMPLEX (HARVEST MIDSTREAM COMPANY) | SUBLETTE COUNTY, Sublette, WY | Pass | State |
| 2026-03-12 | PINEDALE COMPLEX (HARVEST MIDSTREAM COMPANY) | SUBLETTE COUNTY, Sublette, WY | Pass | State |
| 2026-03-12 | PINEDALE COMPLEX (HARVEST MIDSTREAM COMPANY) | SUBLETTE COUNTY, Sublette, WY | Pass | State |
| 2026-03-12 | PINEDALE COMPLEX (HARVEST MIDSTREAM COMPANY) | SUBLETTE COUNTY, Sublette, WY | Pass | State |
| 2026-03-12 | PINEDALE COMPLEX (HARVEST MIDSTREAM COMPANY) | SUBLETTE COUNTY, Sublette, WY | Pass | State |
| 2026-03-12 | PINEDALE COMPLEX (HARVEST MIDSTREAM COMPANY) | SUBLETTE COUNTY, Sublette, WY | Pass | State |
| 2026-03-11 | CHUGACH ELECTRIC ASSOCIATION / GEORGE SULLIVAN PLANT TWO | ANCHORAGE, Anchorage Municipality, AK | Pass | State |
| 2026-03-11 | CHUGACH ELECTRIC ASSOCIATION / GEORGE SULLIVAN PLANT TWO | ANCHORAGE, Anchorage Municipality, AK | Pass | State |
| 2026-03-11 | CULLMAN CASTING CORPORATION | CULLMAN, Cullman, AL | Pass | State |
| 2026-03-11 | CULLMAN CASTING CORPORATION | CULLMAN, Cullman, AL | Pass | State |
| 2026-03-11 | W&T OFFSHORE, INC. | THEODORE, Mobile, AL | Pass | State |
| 2026-03-11 | W&T OFFSHORE, INC. | THEODORE, Mobile, AL | Pass | State |
| 2026-03-11 | W&T OFFSHORE, INC. | THEODORE, Mobile, AL | Pass | State |
| 2026-03-11 | RESOLUTE FP US INC. | COOSA PINES, Talladega, AL | Pass | State |
| 2026-03-11 | DESOTO GATHERING COMPANY, LLC.-STONEFLY CPF 1 | SIDON, Cleburne, AR | Pass | State |
| 2026-03-11 | DESOTO GATHERING COMPANY, LLC.-STONEFLY CPF 1 | SIDON, Cleburne, AR | Pass | State |
| 2026-03-11 | DESOTO GATHERING COMPANY, LLC.-STONEFLY CPF 1 | SIDON, Cleburne, AR | Pass | State |
| 2026-03-11 | FREEPORT-MCMORAN - SAFFORD OPERATIONS | SAFFORD, Graham, AZ | Pass | State |
| 2026-03-11 | EL PASO NATURAL GAS CO - MOJAVE TOPOCK COMPRESSOR STATION | TOPOCK, Mohave, AZ | Pass | State |
| 2026-03-11 | SANTA FE PACIFIC PIPELINES LP | SACRAMENTO, Sacramento, CA | Pending | Local |
| 2026-03-11 | SENTINEL PEAK RESOURCES CA LLC — high-priority violation on file | BAKERSFIELD, Kern, CA | Pass | Local |
| 2026-03-11 | GALLO GLASS CO — high-priority violation on file | MODESTO, Stanislaus, CA | Pass | Local |
| 2026-03-11 | GALLO GLASS CO — high-priority violation on file | MODESTO, Stanislaus, CA | Pass | Local |
| 2026-03-11 | GALLO GLASS CO — high-priority violation on file | MODESTO, Stanislaus, CA | Pass | Local |
| 2026-03-11 | GALLO GLASS CO — high-priority violation on file | MODESTO, Stanislaus, CA | Pass | Local |
| 2026-03-11 | ROCKY MOUNTAIN MIDSTREAM - AUBURN CS | KERSEY AREA, Weld, CO | Pass | State |
| 2026-03-11 | ROCKY MOUNTAIN MIDSTREAM - AUBURN CS | KERSEY AREA, Weld, CO | Pass | State |
| 2026-03-11 | ROCKY MOUNTAIN MIDSTREAM - AUBURN CS | KERSEY AREA, Weld, CO | Pass | State |
| 2026-03-11 | PRATT & WHITNEY, DIVISION OF RTX CORPORATION | MIDDLETOWN, Middlesex, CT | Pass | State |
| 2026-03-11 | AMERICAN UNIVERSITY | WASHINGTON, District of Columbia, DC | Pass | State |
| 2026-03-11 | AMERICAN UNIVERSITY | WASHINGTON, District of Columbia, DC | Pass | State |
| 2026-03-11 | TITAN FLORIDA LLC | MEDLEY, Miami-Dade, FL | Pass | State |
| 2026-03-11 | GERDAU AMERISTEEL US INC. | CARTERSVILLE, Bartow, GA | Pass | State |
| 2026-03-11 | CERTAINTEED LLC — high-priority violation on file | ATHENS, Clarke, GA | Pass | State |
| 2026-03-11 | LOCKHEED MARTIN AERONAUTICS CO. | MARIETTA, Cobb, GA | Pass | State |
Dates as filed by the agency that recorded the stack test. Figures from EPA’s ICIS-AIR download.