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.

What this page shows

This page covers Clean Air Act facilities in the EPA air register with stack tests in SD for 2026. It lists 34 stack tests recorded in 2026.