EPA Air · stack tests by state and year
Air-emissions stack tests in Pennsylvania, 2026
- 501Stack tests
A stack test measures what a source actually emits, at the stack, against the limit in its permit. Every stack test below was recorded against a source in Pennsylvania during 2026; one facility can appear more than once, because this is a record of what happened rather than a list of places.
Counties in Pennsylvania, 2026
- Susquehanna County 117
- Lycoming County 36
- Bradford County 30
- Washington County 29
- Greene County 24
- Philadelphia County 22
- Tioga County 22
- Armstrong County 17
- Wyoming County 13
- Allegheny County 13
- Butler County 12
- Potter County 11
- Mercer County 11
- Westmoreland County 11
- Fayette County 9
- Lawrence County 9
- Montgomery County 7
- Elk County 6
- Lancaster County 6
- York County 6
- Luzerne County 6
- Indiana County 5
- Delaware County 5
- Venango County 5
- Franklin County 5
- Northampton County 5
- Beaver County 4
- Crawford County 4
- Schuylkill County 4
- Dauphin County 4
- Centre County 3
- Jefferson County 3
- Bucks County 3
- Somerset County 3
- Adams County 3
- Bedford County 3
- Berks County 3
Pennsylvania, other years
Air-emissions stack tests recorded in Pennsylvania, 2026
| Date | Facility | Where | Kind | Agency |
|---|---|---|---|---|
| 2026-04-27 | EXPAND OPERATING LLC/WOOSMAN PAD | NEW MILFORD, Susquehanna, PA | Pass | State |
| 2026-04-23 | MAGNESITA REFRACTORIES/YORK — high-priority violation on file | YORK, York, PA | Pass | State |
| 2026-04-23 | EASTERN GAS TRANS & STORAGE INC/STATE LINE STA | GENESEE, Potter, PA | Pass | State |
| 2026-04-23 | ASC ENGINEERED SOLUTIONS LLC/COLUMBIA FKA ANVIL | COLUMBIA, Lancaster, PA | Pass | State |
| 2026-04-23 | NFG MIDSTREAM COVINGTON LLC/SHAW COMP STA | MAINESBURG, Tioga, PA | Pending | State |
| 2026-04-23 | HILCORP ENERGY CO/PULASKI WHITING CTL FAC — high-priority violation on file | EDINBURG, Lawrence, PA | Pass | State |
| 2026-04-23 | RUSSO, B. PAD 1 — high-priority violation on file | SPRINGVILLE, Susquehanna, PA | Pass | State |
| 2026-04-22 | EASTERN GAS TRANS & STORAGE INC/HARRISON STA | HARRISON VALLEY, Potter, PA | Pass | State |
| 2026-04-22 | EQM GATHERING OPCO LLC/TWILIGHT COMP STA | DAISYTOWN, Washington, PA | Pass | State |
| 2026-04-22 | HILCORP ENERGY CO/NCD CENTRAL FAC | NEW CASTLE, Lawrence, PA | Pass | State |
| 2026-04-22 | HILCORP ENERGY CO/MAHONING BUCKER PROD FAC — high-priority violation on file | EDINBURG, Lawrence, PA | Pass | State |
| 2026-04-22 | P&G 2 WELL SITE | TUNKHANNOCK, Wyoming, PA | Pass | State |
| 2026-04-22 | WARRINER, S PAD 1 — high-priority violation on file | MONTROSE, Susquehanna, PA | Pass | State |
| 2026-04-22 | GREENWOOD, R. PAD 2 | MONTROSE, Susquehanna, PA | Pass | State |
| 2026-04-21 | PEOPLES NATURAL GAS CO LLC/GIRTY STA | SHELOCTA, Armstrong, PA | Pass | State |
| 2026-04-21 | WILLIAMS FIELD SVC CO LLC/SNAKE CREEK COMP STA | CLARKS SUMMIT, Susquehanna, PA | Pass | State |
| 2026-04-21 | HILCORP ENERGY CO/JEFFERSON MONTGOMERY STA | JEFFERSON TOWNSHIP, Mercer, PA | Pass | State |
| 2026-04-21 | MOGRIDGE, C. PAD 1 — high-priority violation on file | SPRINGVILLE, Susquehanna, PA | Pending | State |
| 2026-04-20 | LAUREL MTN MIDSTREAM OPR LLC/BROWN COMP STA | GREENSBORO, Greene, PA | Pass | State |
| 2026-04-20 | HILCORP ENERGY CO/MAHONING SIEGEL FACILITY — high-priority violation on file | EDINBURG, Lawrence, PA | Pass | State |
| 2026-04-20 | EMPIRE PIPELINE INC/JACKSON COMP STA | LAWRENCEVILLE, Tioga, PA | Pass | State |
| 2026-04-20 | HILCORP ENERGY CO/NORTH BEAVER KEPHART PROD FAC | ENON VALLEY, Lawrence, PA | Pass | State |
| 2026-04-20 | PENNAY, G PAD 1 | KINGSLEY, Susquehanna, PA | Pass | State |
| 2026-04-20 | TSOUROUS, A. PAD 1 | MONTROSE, Susquehanna, PA | Pass | State |
| 2026-04-17 | NFG MIDSTREAM COVINGTON LLC/KRAUSE COMP STA | MAINESBURG, Tioga, PA | Pass | State |
| 2026-04-17 | HILCORP ENERGY CO/LACKAWANNOCK LARMON CTL FAC | MERCER, Mercer, PA | Pending | State |
| 2026-04-16 | LANCASTER CNTY SWMA/SUSQ RESOURCE MGMT COMPLEX — high-priority violation on file | HARRISBURG, Dauphin, PA | Pass | State |
| 2026-04-16 | REGENCY MARCELLUS GATHERING LLC/BRADFORD WEST COMP STA | GRANVILLE SUMMIT, Bradford, PA | Pass | State |
| 2026-04-16 | NFG MIDSTREAM COVINGTON LLC/DCNR TRACT 595 | ARNOT, Tioga, PA | Pass | State |
| 2026-04-16 | EQM GATHERING OPCO LLC/TERRA COMP STA | PLUM CREEK, Armstrong, PA | Pass | State |
| 2026-04-16 | MARKWEST LIBERTY MIDST & RES/IMPERIAL CIBUS RANCH COMP STA | ROBINSON, Washington, PA | Pass | State |
| 2026-04-16 | WOLF RUN ENERGY LLC/ELECTRIC GENERATION STATION | WYALUSING, Bradford, PA | Pass | State |
| 2026-04-16 | RAG APPLE LLC PAD 1 — high-priority violation on file | MONTROSE, Susquehanna, PA | Pass | State |
| 2026-04-16 | JHHC PAD 1 — high-priority violation on file | MONTROSE, Susquehanna, PA | Pass | State |
| 2026-04-15 | KEYSTONE CONEMAUGH PROJ LLC/CONEMAUGH STATION | NEW FLORENCE, Indiana, PA | Pass | State |
| 2026-04-15 | REGENCY MARCELLUS GAS GATHERING LLC/LONE WALNUT COMP STA | JERSEY SHORE, Lycoming, PA | Pass | State |
| 2026-04-15 | ETC NORTHEAST PIPELINE LLC/RED BEND COMP STA | TROUT RUN, Lycoming, PA | Pass | State |
| 2026-04-15 | WILLIAMS FIELD SVC CO LLC/FRASER COMP STA | MONTROSE, Susquehanna, PA | Pass | State |
| 2026-04-15 | WILLIAMS FIELD SVC CO LLC/MILLER COMP STA | NEW MILFORD, Susquehanna, PA | Pass | State |
| 2026-04-15 | MARKWEST LIBERTY MIDST & RES/IMPERIAL CIBUS RANCH COMP STA | ROBINSON, Washington, PA | Pass | State |
| 2026-04-15 | EXPAND OPERATING LLC/CURTIN WYO PAD | LACEYVILLE, Wyoming, PA | Pass | State |
| 2026-04-15 | EXPAND OPERATING LLC/TIFFANY WYO PAD | LACEYVILLE, Wyoming, PA | Pending | State |
| 2026-04-15 | RUSSO, B. PAD 1 — high-priority violation on file | SPRINGVILLE, Susquehanna, PA | Pending | State |
| 2026-04-14 | NFG MIDSTREAM COVINGTON LLC/STOCK 144 COMP STA | WELLSBORO, Tioga, PA | Pending | State |
| 2026-04-14 | WILLIAMS FIELD SVC CO LLC/NORTHEAST COMP STA | HALLSTEAD, Susquehanna, PA | Pass | State |
| 2026-04-14 | STARZEC, E. PAD 1 | MONTROSE, Susquehanna, PA | Pass | State |
| 2026-04-14 | GEIGER, K. PAD 1 | MONTROSE, Susquehanna, PA | Pass | State |
| 2026-04-13 | DOMTAR PAPER CO/JOHNSONBURG MILL — high-priority violation on file | JOHNSONBURG, Elk, PA | Pass | State |
| 2026-04-13 | CABOT OIL & GAS CORP/BISHOP, B PAD 1 | SPRINGVILLE, Susquehanna, PA | Pass | State |
| 2026-04-13 | LAUFFER, J. PAD 1 — high-priority violation on file | SPRINGVILLE, Susquehanna, PA | Pass | State |
| 2026-04-12 | SCRUBGRASS GENERATING PLT/VENANGO — high-priority violation on file | KENNERDELL, Venango, PA | Pass | State |
| 2026-04-10 | CNX MIDSTREAM OPR CO LLC/BUCKLAND COMP STA | WIND RIDGE, Greene, PA | Pass | State |
| 2026-04-09 | LANCASTER CNTY RRF/ LANCASTER — high-priority violation on file | BAINBRIDGE, Lancaster, PA | Pass | State |
| 2026-04-09 | GREATER HAZLETON JT SEW AUTH/WEST HAZLETON STP — high-priority violation on file | WEST HAZLETON, Luzerne, PA | Pass | State |
| 2026-04-09 | TENNESSEE GAS PIPELINE CO LLC/MERCER STA 219 | MERCER, Mercer, PA | Pass | State |
| 2026-04-09 | MARKWEST LIBERTY MIDSTREAM & RESOURCES/SHAW COMP STA | WASHINGTON, Washington, PA | Pass | State |
| 2026-04-09 | TEXAS EASTERN TRANS LP/CHAMBERSBURG | CHAMBERSBURG, Franklin, PA | Pass | State |
| 2026-04-09 | SQUIER, R. PAD 1 — high-priority violation on file | KINGSLEY, Susquehanna, PA | Pass | State |
| 2026-04-09 | NEXTERA RENEWABLE FUELS LLC/WESTERN BERKS LDFL | BIRDSBORO, Berks, PA | Pass | State |
| 2026-04-08 | TENNESSEE GAS PIPELINE/MARIENVILLE STA 307 | MARIENVILLE, Forest, PA | Pass | State |
| 2026-04-08 | INGENCO WHOLESALE POWER LLC/MTN VIEW LDFL | GREENCASTLE, Franklin, PA | Pass | State |
| 2026-04-08 | STECKMAN RIDGE LP/CLEARVILLE | CLEARVILLE, Bedford, PA | Pass | State |
| 2026-04-08 | WARREN EP INC/REIMILLER PAD | MESHOPPEN, Wyoming, PA | Pass | State |
| 2026-04-07 | TENNESSEE GAS PIPELINE CO LLC/COMP STA 321 | CLIFFORD, Susquehanna, PA | Pass | State |
| 2026-04-07 | SVC MFG INC/MOUNTAIN TOP | MOUNTAIN TOP, Luzerne, PA | Pass | State |
| 2026-04-07 | LEADING TECH/LEECHBURG | LEECHBURG, Armstrong, PA | Pass | State |
| 2026-04-07 | WPX ENERGY APPALACHIA LLC/POWERS SITE | MONTROSE, Susquehanna, PA | Pass | State |
| 2026-04-07 | NFG MIDSTREAM COVINGTON LLC/CLARK COMP STA | MAINESBURG, Tioga, PA | Pass | State |
| 2026-04-06 | SQUIER, R. PAD 1 — high-priority violation on file | KINGSLEY, Susquehanna, PA | Pending | State |
| 2026-04-06 | HUSTON, J. PAD 1 | KINGSLEY, Susquehanna, PA | Pass | State |
| 2026-04-04 | GILBERTON POWER CO/JOHN B RICH MEM POWER STA | FRACKVILLE, Schuylkill, PA | Pass | State |
| 2026-04-02 | REGENCY MARCELLUS GAS GATHERING/CANOE RUN COMP STA | SALLADASBURG, Lycoming, PA | Pass | State |
| 2026-04-02 | NFG MIDSTREAM COVINGTON LLC/NETTERMAN COMP STA | WELLSBORO, Tioga, PA | Pass | State |
| 2026-04-02 | WILLIAMS FIELD SVC CO LLC/CENTRAL COMP STA | MONTROSE, Susquehanna, PA | Pass | State |
| 2026-04-02 | LARUE, C PAD 2 — high-priority violation on file | MONTROSE, Susquehanna, PA | Pass | State |
| 2026-04-02 | BUCKEYE TERMINALS, LLC/INDIANOLA | INDIANOLA, Allegheny, PA | Pass | Local |
| 2026-04-02 | ALLEGHENY CNTY SANI AUTH/ALLEGHENY CNTY | PITTSBURGH, Allegheny, PA | Pass | Local |
| 2026-04-01 | VITRO MEADVILLE FLAT GLASS MEADVILLE PLT/CRAWFORD | COCHRANTON, Crawford, PA | Pass | State |
| 2026-04-01 | PIXELLE SPEC SOLUTIONS LLC/SPRING GROVE — high-priority violation on file | SPRING GROVE, York, PA | Fail | State |
| 2026-04-01 | GRAYMONT PA INC/PLEASANT GAP & CON-LIME & BELLEFONTE PLTS | BELLEFONTE, Centre, PA | Pass | State |
| 2026-04-01 | VICTAULIC COMPANY/ALBURTIS FACILITY | ALBURTIS, Lehigh, PA | Pass | State |
| 2026-04-01 | MARKWEST LIBERTY MIDSTREAM/DRYER BOOSTER COMP STA | AVELLA, Washington, PA | Pass | State |
| 2026-04-01 | CNX MIDSTREAM OPR CO LLC/MAMONT COMP STA | APOLLO, Westmoreland, PA | Pass | State |
| 2026-04-01 | REGENCY MARCELLUS GAS GATHERING LLC/OGONTZ WEST COMP STA | CUMMINS TWP, Lycoming, PA | Pass | State |
| 2026-04-01 | REGENCY MARCELLUS GAS GATHERING LLC/OGONTZ WEST COMP STA | CUMMINS TWP, Lycoming, PA | Pass | State |
| 2026-04-01 | WILLIAMS FIELD SVC CO LLC/SHIELDS COMP STA | SPRINGVILLE, Susquehanna, PA | Pass | State |
| 2026-04-01 | NFG MIDSTREAM CLERMONT LLC/CLERMONT WEST COMP STA | EMPORIUM, Elk, PA | Pass | State |
| 2026-04-01 | SHELL CHEM APPALACHIA/SHELL POLYMERS MONACA — high-priority violation on file | MONACA, Beaver, PA | Pass | State |
| 2026-04-01 | SOUTHWESTERN ENERGY CO/TNT LIMITED PARTNERSHIP WEST 6H | NEW MILFORD, Susquehanna, PA | Pass | State |
| 2026-04-01 | EQM GATHERING OPCO LLC/KRYPTONITE COMP STA | WASHINGTON, Washington, PA | Pass | State |
| 2026-04-01 | POWERS, M. PAD 1 | MESHOPPEN, Susquehanna, PA | Pass | State |
| 2026-04-01 | HAWK, J. PAD 1 | MESHOPPEN, Susquehanna, PA | Pass | State |
| 2026-04-01 | TEMPLE UNIV HEALTH SCIENCES CAMPUS/STEAM — high-priority violation on file | PHILADELPHIA, Philadelphia, PA | Pass | Local |
| 2026-03-31 | WILLIAMS FIELD SVC CO LLC/TEEL COMP STA | SPRINGVILLE, Susquehanna, PA | Pass | State |
| 2026-03-31 | MARKWEST LIBERTY MIDSTREAM/BRIGICH COMP STA | CANONSBURG, Washington, PA | Pass | State |
| 2026-03-31 | EQM GATHERING OPCO LLC/KRYPTONITE COMP STA | WASHINGTON, Washington, PA | Pass | State |
| 2026-03-30 | LAUREL MTN MIDSTREAM OPR LLC/DUNBAR COMP STA | DUNBAR, Fayette, PA | Pass | State |
| 2026-03-30 | RWE HOLDING CO/WEST PITTSBURG PLT — high-priority violation on file | NEW CASTLE, Lawrence, PA | Pass | State |
| 2026-03-27 | SGL CARBON CORP/ST MARYS PLT | SAINT MARYS, Elk, PA | Pending | State |
| 2026-03-27 | PIN OAK MIDSTREAM LLC/HURTT COMP STA | NEW WILMINGTON, Mercer, PA | Pass | State |
Dates as filed by the agency that recorded the stack test. Figures from EPA’s ICIS-AIR download.