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 |
|---|---|---|---|---|
| 2026-08-19 | US DOD/RAVEN ROCK MTN COMPLEX | BLUE RIDGE SUMMIT, Adams, PA | Pass | State |
| 2026-08-13 | HERSHEY CO/WWTP | HERSHEY, Dauphin, PA | Pass | State |
| 2026-08-06 | EQT MIDSTREAM COMPANY LLC/DEEMSTON WICKS COMP STA | FREDERICKTOWN, Washington, PA | Pass | State |
| 2026-08-05 | TEXAS EASTERN TRANS LP/HOLBROOK STA | WIND RIDGE, Greene, PA | Pass | State |
| 2026-08-05 | ETC NORTHEAST FLD SVC LLC/PIKE COMP STA | ROCHESTER, Beaver, PA | Pass | State |
| 2026-08-04 | ALTA PERFORMANCE MATERIALS US, LLC | PITTSBURGH, Allegheny, PA | Pass | Local |
| 2026-08-04 | ADVANSIX (FORMERLY HONEYWELL/FRANKFORD PLT) — high-priority violation on file | PHILADELPHIA, Philadelphia, PA | Pending | Local |
| 2026-08-03 | CONSOL PA COAL CO LLC/BAILEY PREP PLT — high-priority violation on file | WEST FINLEY, Greene, PA | Pass | State |
| 2026-07-29 | LAUREL MTN MIDSTREAM OPR LLC/SHAMROCK COMP STA — high-priority violation on file | SALEM, Fayette, PA | Pass | State |
| 2026-07-28 | HERMITAGE MUNI AUTH/HERMITAGE WPCP | HERMITAGE, Mercer, PA | Pass | State |
| 2026-07-27 | ABBOTT, M. PAD 1 | NEW MILFORD, Susquehanna, PA | Pass | State |
| 2026-07-23 | COLUMBIA GAS TRANS CORP/SALISBURY COMP STA | SALISBURY, Somerset, PA | Pass | State |
| 2026-07-23 | MARKWEST LIBERTY BLUESTONE LLC/TRILLITH COMP STA | HARMONY, Butler, PA | Pass | State |
| 2026-07-23 | HEP PENNSYLVANIA GATHERING LLC/WHITE CPF 1 COMP STA | STEVENSVILLE, Bradford, PA | Pass | State |
| 2026-07-23 | WRIGHT, W. PAD 1 | MONTROSE, Susquehanna, PA | Pass | State |
| 2026-07-23 | VANDERMARK, R. PAD 1 | MONTROSE, Susquehanna, PA | Pass | State |
| 2026-07-22 | GENTEX CORP/SIMPSON PROT CLOTHING | SIMPSON, Lackawanna, PA | Pass | State |
| 2026-07-22 | TEXAS EASTERN TRANS LP/BECHTELSVILLE | BECHTELSVILLE, Berks, PA | Pass | State |
| 2026-07-22 | UGI MORAINE EAST GATHERING LLC/RENICK COMP STA | WEST SUNBURY, Butler, PA | Pass | State |
| 2026-07-22 | CABOT OIL & GAS CORP/JEFFERS FARMS PAD 5 | GIBSON, Susquehanna, PA | Pass | State |
| 2026-07-22 | KING, D. PAD 1 — high-priority violation on file | SPRINGVILLE, Susquehanna, PA | Pass | State |
| 2026-07-21 | MARKWEST LIBERTY BLUESTONE LLC/ROYAL OAK COMP STA | EVANS CITY, Butler, PA | Pass | State |
| 2026-07-21 | KING, D. PAD 1 — high-priority violation on file | SPRINGVILLE, Susquehanna, PA | Pending | State |
| 2026-07-21 | WOOD, E. PAD 1 | MONTROSE, Susquehanna, PA | Pass | State |
| 2026-07-20 | CABOT OIL & GAS CORP/JEFFERS FARMS PAD 5 | GIBSON, Susquehanna, PA | Pending | State |
| 2026-07-20 | CABOT OIL & GAS CORP/FOLTZ J PAD 1 | HOP BOTTOM, Susquehanna, PA | Pass | State |
| 2026-07-19 | HILLTOP ENERGY CENTER LLC/CARMICHAELS | CARMICHAELS, Greene, PA | Pass | State |
| 2026-07-17 | PRECISION CAPITAL, LP PAD 1 | HOP BOTTOM, Susquehanna, PA | Pass | State |
| 2026-07-16 | NORTHUMBERLAND TERM DE LLC/NORTHUMBERLAND TERM | NORTHUMBERLAND, Northumberland, PA | Pass | State |
| 2026-07-16 | SUSQUEHANNA GATHERING/CDP 1 COMP STA | NEW MILFORD, Susquehanna, PA | Pass | State |
| 2026-07-16 | CABOT OIL & GAS CORP/TEDDICK, M. PAD 1 | KINGSLEY, Susquehanna, PA | Pass | State |
| 2026-07-15 | WILLIAMS FIELD SVC CO LLC/KANE ROAD COMP STA | MONTROSE, Susquehanna, PA | Pass | State |
| 2026-07-15 | HALLIDAY, A. PAD 1 | MONTROSE, Susquehanna, PA | Pass | State |
| 2026-07-15 | TUCKER, H. PAD 1 | MONTROSE, Susquehanna, PA | Pass | State |
| 2026-07-15 | RANGE RESOURCES APPALACHIA LLC/17 - 22 WELL PAD | TROUT RUN, Lycoming, PA | Pass | State |
| 2026-07-15 | RANGE RESOURCES APPALACHIA LLC/17 - 22 WELL PAD | TROUT RUN, Lycoming, PA | Pass | State |
| 2026-07-14 | NORTHUMBERLAND TERM DE LLC/NORTHUMBERLAND TERM | NORTHUMBERLAND, Northumberland, PA | Pass | State |
| 2026-07-14 | FLOWER, T. PAD 1 | MESHOPPEN, Susquehanna, PA | Pass | State |
| 2026-07-13 | MARKWEST LIBERTY MIDSTREAM & RESOURCES/JOHNSTON COMP STA | CANONSBURG, Washington, PA | Pass | State |
| 2026-07-13 | WCAA MIDSTREAM LLC/WEITZ SOUTH 20 COMP STA | ADAMSBURG, Westmoreland, PA | Pass | State |
| 2026-07-13 | BENEDIKT, K. PAD 1 | MONTROSE, Susquehanna, PA | Pass | State |
| 2026-07-09 | HEP PA GATHERING LLC/GREENZWEIG COMP STA | WYALUSING, Bradford, PA | Pass | State |
| 2026-07-09 | COTERRA ENERGY INC/ADAMS J PAD 1 | KINGSLEY, Susquehanna, PA | Pass | State |
| 2026-07-09 | PAYNE, D. PAD 1 | NEW MILFORD, Susquehanna, PA | Pass | State |
| 2026-07-08 | PA STATE UNIV/MILTON S HERSHEY MED CTR | HERSHEY, Dauphin, PA | Pass | State |
| 2026-07-08 | SUSQUEHANNA GATHERING/NORTH RANGE CPF 1 COMP STA | SUSQUEHANNA, Susquehanna, PA | Pass | State |
| 2026-07-07 | HEP PENNSYLVANIA GATHERING LLC/CLARK CPF 1 COMP STA | WYSOX, Bradford, PA | Pass | State |
| 2026-07-02 | CABOT OIL & GAS CORP/MAKOSKY T PAD 1 | KINGSLEY, Susquehanna, PA | Pass | State |
| 2026-07-02 | COTERRA ENERGY INC/HAYNES W PAD 1 | NEW MILFORD, Susquehanna, PA | Pass | State |
| 2026-07-01 | EQM GATHERING OPCO LLC/BLUE MOON COMP STA | DAISYTOWN, Washington, PA | Pass | State |
| 2026-07-01 | CABOT OIL & GAS CORP/KROPA, T. PAD 1 | SPRINGVILLE, Susquehanna, PA | Pass | State |
| 2026-07-01 | AUSTIN, E. PAD 1 | HOP BOTTOM, Susquehanna, PA | Pass | State |
| 2026-06-30 | GLAXO SMITHKLINE/UPPER PROVIDENCE — high-priority violation on file | COLLEGEVILLE, Montgomery, PA | Pass | State |
| 2026-06-30 | WILLIAMS FIELD SVC CO LLC/WILCOX COMP STA | TUNKHANNOCK, Wyoming, PA | Pass | State |
| 2026-06-30 | PINE RUN MIDSTREAM LLC/BASS COMP STA | SAXONBURG, Butler, PA | Pass | State |
| 2026-06-30 | WILLIAMS FIELD SVC CO LLC/WHITE COMP STA | SPRINGVILLE, Susquehanna, PA | Pass | State |
| 2026-06-30 | EQT ARO LLC/BIEBER SISTERS COMP STA | TROUT RUN, Lycoming, PA | Pass | State |
| 2026-06-29 | APPALACHIA MIDSTREAM SVC LLC/RATTLESNAKE HILL COMP STA | AUBURN TOWNSHIP, Susquehanna, PA | Pass | State |
| 2026-06-29 | COMBINED METAL IND NEW CASTLE FAC — high-priority violation on file | NEW CASTLE, Lawrence, PA | Pass | State |
| 2026-06-29 | EQT ARO LLC/SALT RUN A COMP STA | TROUT RUN, Lycoming, PA | Pass | State |
| 2026-06-29 | EQT ARO LLC/SALT RUN A COMP STA | TROUT RUN, Lycoming, PA | Pass | State |
| 2026-06-26 | COMMERCIAL ASPHALT SUPPLY/FENELTON | FENELTON, Butler, PA | Fail | State |
| 2026-06-26 | EXPAND OPERATING LLC/ADAMS WYO PAD | LACEYVILLE, Wyoming, PA | Pass | State |
| 2026-06-26 | RU-05 DRANN PAD | NEW MILFORD, Susquehanna, PA | Pass | State |
| 2026-06-26 | ADVANSIX (FORMERLY HONEYWELL/FRANKFORD PLT) — high-priority violation on file | PHILADELPHIA, Philadelphia, PA | Pending | Local |
| 2026-06-25 | PEOPLES NATURAL GAS CO LLC/VALLEY STA | YATESBORO, Armstrong, PA | Pass | State |
| 2026-06-25 | ADVANSIX (FORMERLY HONEYWELL/FRANKFORD PLT) — high-priority violation on file | PHILADELPHIA, Philadelphia, PA | Pending | Local |
| 2026-06-24 | COLUMBIA GAS TRANS CORP/DONEGAL COMP STA | WEST ALEXANDER, Washington, PA | Pass | State |
| 2026-06-24 | SOUTHWESTERN ENERGY CO/RACINE 5H | NEW MILFORD, Susquehanna, PA | Pass | State |
| 2026-06-23 | TEXAS EASTERN TRANS LP/UNIONTOWN STA — high-priority violation on file | LEMONT FURNACE, Fayette, PA | Pass | State |
| 2026-06-23 | CONSOL PA COAL CO LLC/BAILEY PREP PLT — high-priority violation on file | WEST FINLEY, Greene, PA | Pass | State |
| 2026-06-23 | BUCKEYE TERM LLC/MALVERN TERM | MALVERN, Chester, PA | Pass | State |
| 2026-06-23 | MARKWEST LIBERTY MIDSTREAM & RESOURCES/NANCY STEWART | MOUNT PLEASANT, Washington, PA | Pass | State |
| 2026-06-23 | EXPAND RUTH WYO PAD | MESHOPPEN, Wyoming, PA | Pass | State |
| 2026-06-23 | EQT ARTEMIS MIDSTREAM LLC/GUARDIAN COMP STA | IRWIN, Westmoreland, PA | Pass | State |
| 2026-06-22 | LONGHORN PAD C/ELK | WEEDVILLE, Elk, PA | Pass | State |
| 2026-06-19 | SCRUBGRASS GENERATING PLT/VENANGO — high-priority violation on file | KENNERDELL, Venango, PA | Pass | State |
| 2026-06-19 | REGENCY MARCELLUS GAS GATHERING LLC/QUAKER STATE RD COMP STA | MONTOURSVILLE, Lycoming, PA | Pass | State |
| 2026-06-19 | CNX MIDSTREAM OPR CO LLC /MORRIS DEHY STATION | GRAYSVILLE, Greene, PA | Pass | State |
| 2026-06-19 | USS/CLAIRTON WORKS — high-priority violation on file | CLAIRTON, Allegheny, PA | Pass | Local |
| 2026-06-19 | ADVANSIX (FORMERLY HONEYWELL/FRANKFORD PLT) — high-priority violation on file | PHILADELPHIA, Philadelphia, PA | Pending | Local |
| 2026-06-18 | LORD CORP/CAMBRIDGE SPRINGS | CAMBRIDGE SPRINGS, Crawford, PA | Pass | State |
| 2026-06-18 | ARDAGH GLASS INC/PORT ALLEGANY PLT — high-priority violation on file | PORT ALLEGANY, McKean, PA | Pass | State |
| 2026-06-18 | SUSQUEHANNA GATHERING CO 1 LLC/CDP 3 | NEW MILFORD, Susquehanna, PA | Pass | State |
| 2026-06-17 | SUNOCO LLC/MH RACE FUELS — high-priority violation on file | MARCUS HOOK, Delaware, PA | Pass | State |
| 2026-06-17 | EQT PROD CO/MOJO COMPRESSOR UNIT | WASHINGTON, Washington, PA | Pass | State |
| 2026-06-17 | NFG MIDSTREAM TROUT RUN LLC/HAGERMAN GAS & PROC METERING FAC | TROUT RUN, Lycoming, PA | Pass | State |
| 2026-06-17 | ADVANSIX (FORMERLY HONEYWELL/FRANKFORD PLT) — high-priority violation on file | PHILADELPHIA, Philadelphia, PA | Pending | Local |
| 2026-06-16 | GOLDEN EAGLE CONST CO/EIGHTY FOUR PLT | EIGHTY FOUR, Washington, PA | Pending | State |
| 2026-06-16 | ADVANSIX (FORMERLY HONEYWELL/FRANKFORD PLT) — high-priority violation on file | PHILADELPHIA, Philadelphia, PA | Pending | Local |
| 2026-06-15 | UGI TEXAS CREEK LLC/CLEGG COMP STA | TROUT RUN, Lycoming, PA | Pass | State |
| 2026-06-12 | PA STATE SYS OF HIGHER ED/INDIANA UNIV | INDIANA, Indiana, PA | Pass | State |
| 2026-06-12 | PA DEPT OF CORR/LAUREL HIGHLANDS SCI | SOMERSET, Somerset, PA | Pass | State |
| 2026-06-12 | HEIDELBERG MATERIALS US CEMENT LLC/NAZARETH | NAZARETH, Northampton, PA | Pass | State |
| 2026-06-12 | BLACKHILL ENERGY LLC/BRADFORD CNTY COMP STA | COLUMBIA CROSS ROADS, Bradford, PA | Pass | State |
| 2026-06-11 | SCRUBGRASS GENERATING PLT/VENANGO — high-priority violation on file | KENNERDELL, Venango, PA | Pass | State |
| 2026-06-11 | EASTERN GAS TRANS & STORAGE INC/GREENLICK STA | STEWARDSON TWP, Potter, PA | Pass | State |
| 2026-06-11 | BUCK CO LLC/QUARRYVILLE — high-priority violation on file | QUARRYVILLE, Lancaster, PA | Pass | State |
| 2026-06-11 | PANTHER CREEK POWER OPR LLC/NESQUEHONING | NESQUEHONING, Carbon, PA | Pass | State |
| 2026-06-11 | DIVERSIFIED PROD LLC/HOMER CITY COMP STA | INDIANA, Indiana, PA | Pass | State |
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Dates as filed by the agency that recorded the stack test. Figures from EPA’s ICIS-AIR download.