EPA Air · stack tests by county and year

Air-emissions stack tests in Yellowstone County, Montana, 2021

67Stack tests

A stack test measures what a source actually emits, at the stack, against the limit in its permit. Each row below is one stack test recorded against a source in Yellowstone County, Montana during 2021. A facility can appear several times: this is the year’s record of what happened, not a list of places. The sources themselves are on the Yellowstone County facility page.

Yellowstone County, Montana, 2021

Air-emissions stack tests in Yellowstone County, other years

Air-emissions stack tests recorded in Yellowstone County, Montana, 2021

Date	Facility	Kind	Agency
2021-12-30	PAR MONTANA BILLINGS REFINERY	Pass	State
2021-12-22	WESTERN SUGAR COOPERATIVE — high-priority violation on file	Pass	State
2021-11-22	MONTANA SULPHUR & CHEMICAL	Pass	State
2021-11-22	MONTANA SULPHUR & CHEMICAL	Pass	State
2021-10-28	YELLOWSTONE POWER PLANT — high-priority violation on file	Pass	State
2021-10-14	CHS INC REFINERY LAUREL	Pass	State
2021-10-14	CHS INC REFINERY LAUREL	Pass	State
2021-08-19	CHS INC REFINERY LAUREL	Pass	State
2021-08-18	CHS INC REFINERY LAUREL	Pass	State
2021-08-16	CHS INC REFINERY LAUREL	Pass	State
2021-08-16	CHS INC REFINERY LAUREL	Pass	State
2021-08-16	CHS INC REFINERY LAUREL	Pass	State
2021-08-16	CHS INC REFINERY LAUREL	Pass	State
2021-08-16	CHS INC REFINERY LAUREL	Pass	State
2021-08-04	CHS INC REFINERY LAUREL	Pass	State
2021-08-04	CHS INC REFINERY LAUREL	Pass	State
2021-07-22	CHS INC REFINERY LAUREL	Pass	State
2021-07-22	CHS INC REFINERY LAUREL	Pass	State
2021-07-22	CHS INC REFINERY LAUREL	Pass	State
2021-07-22	CHS INC REFINERY LAUREL	Pass	State
2021-07-22	CHS INC REFINERY LAUREL	Pass	State
2021-07-22	CHS INC REFINERY LAUREL	Pass	State
2021-07-22	CHS INC REFINERY LAUREL	Pass	State
2021-07-22	CHS INC REFINERY LAUREL	Pass	State
2021-07-22	CHS INC REFINERY LAUREL	Pass	State
2021-07-22	CHS INC REFINERY LAUREL	Pass	State
2021-07-22	CHS INC REFINERY LAUREL	Pass	State
2021-07-22	CHS INC REFINERY LAUREL	Pass	State
2021-07-22	CHS INC REFINERY LAUREL	Pass	State
2021-07-09	PAR MONTANA BULK TERMINAL	Pass	State
2021-07-07	CHS INC REFINERY LAUREL	Pass	State
2021-07-07	CHS INC REFINERY LAUREL	Pass	State
2021-07-07	CHS INC REFINERY LAUREL	Pass	State
2021-07-07	CHS INC REFINERY LAUREL	Pass	State
2021-07-07	CHS INC REFINERY LAUREL	Pass	State
2021-07-07	CHS INC REFINERY LAUREL	Pass	State
2021-06-04	PAR MONTANA BILLINGS REFINERY	Pass	State
2021-06-04	PAR MONTANA BILLINGS REFINERY	Pass	State
2021-06-04	PAR MONTANA BILLINGS REFINERY	Pass	State
2021-05-25	BILLINGS REFINERY	Pass	State
2021-05-05	YELLOWSTONE POWER PLANT — high-priority violation on file	Pass	State
2021-05-03	YELLOWSTONE POWER PLANT — high-priority violation on file	Pass	State
2021-04-19	CHS INC REFINERY LAUREL	Pass	State
2021-04-19	CHS INC REFINERY LAUREL	Pass	State
2021-04-19	CHS INC REFINERY LAUREL	Pass	State
2021-04-19	CHS INC REFINERY LAUREL	Pass	State
2021-03-01	BILLINGS REFINERY	Pass	State
2021-02-02	BILLINGS REFINERY	Pass	State
2021-02-02	BILLINGS REFINERY	Pass	State
2021-01-18	BILLINGS REFINERY	Pass	State
2021-01-15	WESTERN SUGAR COOPERATIVE — high-priority violation on file	Pass	State
2021-01-15	MONTANA SULPHUR & CHEMICAL	Pass	State
2021-01-14	WESTERN SUGAR COOPERATIVE — high-priority violation on file	Pass	State
2021-01-14	WESTERN SUGAR COOPERATIVE — high-priority violation on file	Pass	State
2021-01-14	WESTERN SUGAR COOPERATIVE — high-priority violation on file	Pass	State
2021-01-12	BILLINGS REFINERY	Pass	State
2021-01-12	BILLINGS REFINERY	Pass	State
2021-01-12	BILLINGS REFINERY	Pass	State
2021-01-12	BILLINGS REFINERY	Pass	State
2021-01-12	BILLINGS REFINERY	Pass	State
2021-01-12	BILLINGS REFINERY	Pass	State
2021-01-12	BILLINGS REFINERY	Pass	State
2021-01-12	PAR MONTANA BILLINGS REFINERY	Pass	State
2021-01-06	BILLINGS REFINERY	Pass	State
2021-01-05	BILLINGS REFINERY	Pass	State
2021-01-05	BILLINGS REFINERY	Pass	State
2021-01-05	BILLINGS REFINERY	Pass	State

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