EPA Air · stack tests by state and year

Air-emissions stack tests in South Dakota, 2026

34Stack 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 South Dakota 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 South Dakota, 2026

South Dakota, other years

Air-emissions stack tests recorded in South Dakota, 2026

Date	Facility	Where	Kind	Agency
2026-08-04	VALERO RENEWABLE FUELS COMPANY LLC — high-priority violation on file	AURORA, Brookings, SD	Pass	State
2026-06-24	POET BIOREFINING - MITCHELL LLC	MITCHELL, Davison, SD	Pass	State
2026-06-23	POET BIOREFINING - MITCHELL LLC	MITCHELL, Davison, SD	Pass	State
2026-06-19	GCC DACOTAH — high-priority violation on file	RAPID CITY, Pennington, SD	Pass	State
2026-06-18	GCC DACOTAH — high-priority violation on file	RAPID CITY, Pennington, SD	Pass	State
2026-06-16	OTTER TAIL POWER COMPANY	BIG STONE CITY, Grant, SD	Pass	State
2026-06-16	GCC DACOTAH — high-priority violation on file	RAPID CITY, Pennington, SD	Pass	State
2026-06-03	OTTER TAIL POWER COMPANY - ASTORIA STATION	ASTORIA, Deuel, SD	Pass	State
2026-05-29	RING NECK ENERGY & FEED LLC — high-priority violation on file	ONIDA, Sully, SD	Pass	State
2026-05-28	RING NECK ENERGY & FEED LLC — high-priority violation on file	ONIDA, Sully, SD	Pass	State
2026-05-19	NORTHERN STATES POWER COMPANY	SIOUX FALLS, Minnehaha, SD	Pass	State
2026-05-12	PETE LIEN & SONS, INC. MAIN PLANT	RAPID CITY, Pennington, SD	Pass	State
2026-05-06	BLACK HILLS POWER, INC. (LANGE)	RAPID CITY, Pennington, SD	Pass	State
2026-04-29	PETE LIEN & SONS, INC. MAIN PLANT	RAPID CITY, Pennington, SD	Pass	State
2026-04-28	OTTER TAIL POWER COMPANY - ASTORIA STATION	ASTORIA, Deuel, SD	Pass	State
2026-04-28	MAGELLAN PIPELINE COMPANY LP - SIOUX FALLS TERMINAL	SIOUX FALLS, Minnehaha, SD	Pass	State
2026-04-28	PETE LIEN & SONS, INC. MAIN PLANT	RAPID CITY, Pennington, SD	Pass	State
2026-04-16	PETE LIEN & SONS, INC. MAIN PLANT	RAPID CITY, Pennington, SD	Pass	State
2026-03-31	BASIN ELECTRIC POWER COOPERATIVE GROTON GENERATING	GROTON, Brown, SD	Pass	State
2026-03-30	HIGH PLAINS PROCESSING, LLC, A DELAWARE LIMITED LIABILITY	MITCHELL, Davison, SD	Pass	State
2026-03-10	AG PROCESSING INC.	ABERDEEN, Brown, SD	Pass	State
2026-03-10	HIGH PLAINS PROCESSING, LLC, A DELAWARE LIMITED LIABILITY	MITCHELL, Davison, SD	Pass	State
2026-02-17	WILLOW LAKE COMPRESSOR STATION	WILLOW LAKE, Clark, SD	Pass	State
2026-02-17	PETE LIEN & SONS, INC. MAIN PLANT	RAPID CITY, Pennington, SD	Pass	State
2026-02-12	HIGH PLAINS PROCESSING, LLC, A DELAWARE LIMITED LIABILITY	MITCHELL, Davison, SD	Pass	State
2026-02-11	NUGEN ENERGY LLC — high-priority violation on file	MARION, Turner, SD	Pass	State
2026-02-10	HIGH PLAINS PROCESSING, LLC, A DELAWARE LIMITED LIABILITY	MITCHELL, Davison, SD	Pass	State
2026-02-09	HIGH PLAINS PROCESSING, LLC, A DELAWARE LIMITED LIABILITY	MITCHELL, Davison, SD	Pass	State
2026-02-07	HIGH PLAINS PROCESSING, LLC, A DELAWARE LIMITED LIABILITY	MITCHELL, Davison, SD	Pass	State
2026-02-05	HIGH PLAINS PROCESSING, LLC, A DELAWARE LIMITED LIABILITY	MITCHELL, Davison, SD	Pass	State
2026-02-04	HIGH PLAINS PROCESSING, LLC, A DELAWARE LIMITED LIABILITY	MITCHELL, Davison, SD	Pass	State
2026-02-03	HIGH PLAINS PROCESSING, LLC, A DELAWARE LIMITED LIABILITY	MITCHELL, Davison, SD	Pass	State
2026-01-27	REDFIELD ENERGY LLC — high-priority violation on file	REDFIELD, Beadle, SD	Pass	State
2026-01-07	HUB CITY ENERGY, LLC — high-priority violation on file	ABERDEEN, Brown, SD	Pass	State

Dates as filed by the agency that recorded the stack test. Figures from EPA’s ICIS-AIR download.