THOMAS HILL ENERGY CENTER — Emissions Trend

Clifton Hill, MO · 2019–2023 · Parent: ASSOCIATED ELECTRIC COOPERATIVE INC

This page assembles 5 consecutive years of EPA Toxics Release Inventory Form R filings for THOMAS HILL ENERGY CENTER, spanning 2019–2023. Each annual total aggregates on-site air emissions, surface-water discharges, land disposal, and off-site transfers reported by the facility under EPCRA Section 313, which requires disclosure whenever a listed chemical is manufactured, processed, or otherwise used above threshold quantities.

Reported releases opened at 1.3M in 2019 and closed at 1.0M in 2023 — a decreasing of -18.1% over the window. The chart below stacks the four TRI release media (air, water, land, off-site) and overlays the yearly total. The top contributor by cumulative mass is Barium compounds (except for barium sulfate (CAS No. 7727-43-7)) at 2.4M, followed by Hydrogen fluoride at 1.2M.

Because TRI figures are estimated, not metered, year-over-year deltas can reflect methodology revisions, ownership changes, or shifts in what a facility classifies as reportable — not only physical emission changes. Treat the trajectory as a disclosure record, and cross-reference with the EPA Enforcement and Compliance History Online (ECHO) system for the fuller regulatory picture on this electric utilities facility.

Overall Trend
↓ Decreasing (-18.1%)
2019 Total
1.3M lbs
2023 Total
1.0M lbs

Total Releases by Category

Air
Water
Land
Offsite Transfer
0253.8K507.6K761.3K1.0M1.3M 20192020202120222023 Pounds Released

Year-over-Year Comparison

Year Total Chemicals YoY Change
2019 1.3M lbs 13
2020 734.6K lbs 12 -42.1%
2021 1.0M lbs 14 +37.6%
2022 1.2M lbs 12 +22.0%
2023 1.0M lbs 12 -15.7%

Top Chemicals by Year

Chemical 20192020202120222023 Total
Barium compounds (except for barium sulfate (CAS No. 7727-43-7)) 724.2K 432.7K 511.0K 697.7K 2.4M
Hydrogen fluoride 264.0K 216.7K 281.8K 223.0K 180.4K 1.2M
Barium And Barium Compounds 820.6K 820.6K
Ammonia 134.8K 105.3K 34.3K 36.8K 311.2K
Sulfuric acid (acid aerosols including mists, vapors, gas, fog, and other airborne forms of any particle size) 47.3K 20.7K 38.0K 29.7K 25.7K 161.4K
Vanadium compounds 27.1K 17.1K 16.5K 52.8K 46.6K 160.1K
Copper compounds 19.4K 12.0K 13.9K 18.8K 64.2K
Hydrochloric acid (acid aerosols including mists, vapors, gas, fog, and other airborne forms of any particle size) 13.1K 10.9K 13.6K 11.2K 10.5K 59.3K
Zinc compounds 13.2K 7.1K 6.6K 15.1K 8.4K 50.4K
Manganese compounds 14.9K 9.4K 11.4K 13.8K 49.5K
Copper And Copper Compounds 23.0K 23.0K
Lead compounds 4.8K 3.1K 3.0K 6.5K 93 17.4K
Manganese And Manganese Compounds 16.6K 16.6K
Chromium compounds (except for chromite ore mined in the Transvaal Region) 5.9K 4.8K 4.9K 15.5K
Nickel 4.8K 4.8K

About This Data

Trend data is sourced from the EPA Toxic Release Inventory (TRI). Facilities report annually. Release quantities are self-reported estimates. Year-over-year changes may reflect changes in production, pollution control measures, reporting methodology, or chemical thresholds.

A decrease in reported releases does not necessarily indicate improved environmental performance, as it may reflect production cutbacks, facility closures, or changes in reporting requirements. Similarly, increases may reflect expanded production rather than degraded environmental practices.

Frequently Asked Questions

Is THOMAS HILL ENERGY CENTER getting cleaner or dirtier?
Based on EPA TRI data from 2019–2023, THOMAS HILL ENERGY CENTER's total toxic releases have decreased by approximately 18%.
What time period does this trend data cover?
This page shows 5 years of EPA Toxic Release Inventory data from 2019–2023. Release quantities are self-reported estimates filed annually by the facility.