EPA Air · stack tests by county, year by year

Air-emissions stack tests in Williamson County, Illinois, year by year

• 49Stack tests

A stack test measures what a source actually emits, at the stack, against the limit in its permit. Every year on record for Williamson County, Illinois, most recent first. Each year page lists the events recorded at sources in the county that year.

Williamson County, Illinois, by year

• 2026 19
• 2025 16
• 2023 4
• 2019 3
• 2018 7

All sources in Williamson County →

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