Non-Compliance
TRI Reporter
Clean Water Act
RCRA
STILLWATER MINING CO EAST BOULDER MINE
Quick Summary
- •Released 326,302 lbs of toxic chemicals to the environment in the most recent TRI reporting year.
- •Currently out of compliance in at least one environmental program (CAA, CWA, or RCRA).
- •Assessed $0 in total penalties since records began.
- •Reports releases of chemicals classified as known or probable carcinogens.
- Address
-
EAST BOULDER ROAD
BIG TIMBER, MT 59011
View on map ↗ - County
- SWEET GRASS County
- Industry
- Mining, Quarrying, and Oil and Gas Extraction
- NAICS (North American Industry Classification)
- 212290
- Inspections
- 1 · last Aug 3, 2022
- Total Penalties
- $0 · last Aug 13, 2015
- Registry ID
- 110007110474
How This Compares
#6
of 55 TRI reporters in MT
#75
of 555 TRI reporters in Mining, Quarrying, and Oil and Gas Extraction
Ranked by most recent year's total TRI releases.
Compliance Status (Last 12 Quarters)
Number of calendar quarters, out of the last 12, in which this facility was in violation of its permit. Zero means no recorded violations in that program over the past three years.
10
Water (CWA)
Qtrs Non-Compliant
Qtrs Non-Compliant
0
Hazardous Waste (RCRA)
Qtrs Non-Compliant
Qtrs Non-Compliant
TRI Toxic Chemical Releases
Annual pounds of each toxic chemical released to air, water, and land, as reported to the EPA Toxic Release Inventory. Carcinogen (♦) and PFAS designations are per EPA and IARC classifications.
Emissions Trend (2015–2024)
+13% overall
| Year | Total Releases (lbs) | vs Prior Year |
|---|---|---|
| 2015 | 329,442 | — |
| 2016 | 332,254 | +1% |
| 2017 | 326,302 | -2% |
| 2018 | 345,518 | +6% |
| 2019 | 146,780 | -58% |
| 2020 | 416,755 | +184% |
| 2021 | 447,481 | +7% |
| 2022 | 285,545 | -36% |
| 2023 | 409,458 | +43% |
| 2024 | 373,576 | -9% |
2024
| Chemical | Total (lbs) | Air | Water | Land | Off-Site | |
|---|---|---|---|---|---|---|
| Styrene | — | — | — | — | — | ♦ Carcinogen |
| Nickel compounds | 209,279 | 69 | — | 209,210 | — | ♦ Carcinogen |
| Chromium compounds (except for chromite ore mined in the Transvaal Region) | 69,740 | 3 | — | 69,737 | — | |
| Methanol | 54,906 | 105 | — | 54,801 | — | |
| Copper compounds | 37,012 | 20 | — | 36,992 | — | |
| Propylene | 2,136 | 2,136 | — | — | — | |
| Nitrate compounds (water dissociable; reportable only when in aqueous solution) | 493 | — | — | 493 | — | |
| Lead compounds | 9 | 0 | — | 9 | — |
2023
| Chemical | Total (lbs) | Air | Water | Land | Off-Site | |
|---|---|---|---|---|---|---|
| Styrene | — | — | — | — | — | ♦ Carcinogen |
| Nickel compounds | 284,640 | 89 | — | 284,551 | — | ♦ Carcinogen |
| Chromium compounds (except for chromite ore mined in the Transvaal Region) | 60,077 | 5 | — | 60,072 | — | |
| Methanol | 34,967 | 105 | — | 34,862 | — | |
| Copper compounds | 26,710 | 28 | — | 26,682 | — | |
| Propylene | 2,088 | 2,088 | — | — | — | |
| Nitrate compounds (water dissociable; reportable only when in aqueous solution) | 949 | — | — | 949 | — | |
| Lead compounds | 27 | 0 | — | 27 | — |
2022
| Chemical | Total (lbs) | Air | Water | Land | Off-Site | |
|---|---|---|---|---|---|---|
| Styrene | — | — | — | — | — | ♦ Carcinogen |
| Nickel compounds | 152,500 | 73 | — | 152,427 | — | ♦ Carcinogen |
| Methanol | 51,660 | 106 | — | 51,554 | — | |
| Chromium compounds (except for chromite ore mined in the Transvaal Region) | 47,955 | 4 | — | 47,951 | — | |
| Copper compounds | 30,540 | 26 | — | 30,514 | — | |
| Propylene | 2,075 | 2,075 | — | — | — | |
| Nitrate compounds (water dissociable; reportable only when in aqueous solution) | 751 | — | — | 751 | — | |
| Mercury compounds | 45 | 2 | — | 43 | — | |
| Lead compounds | 20 | 0 | — | 20 | — |
2021
| Chemical | Total (lbs) | Air | Water | Land | Off-Site | |
|---|---|---|---|---|---|---|
| Nickel compounds | 259,067 | 67 | — | 259,000 | — | ♦ Carcinogen |
| Chromium compounds (except for chromite ore mined in the Transvaal Region) | 80,000 | — | — | 80,000 | — | |
| Copper compounds | 56,000 | — | — | 56,000 | — | |
| Methanol | 48,892 | 108 | — | 48,784 | — | |
| Lead compounds | 2,722 | 0 | — | 2,722 | — | |
| Nitrate compounds (water dissociable; reportable only when in aqueous solution) | 800 | — | — | 800 | — |
2020
| Chemical | Total (lbs) | Air | Water | Land | Off-Site | |
|---|---|---|---|---|---|---|
| Nitrate compounds (water dissociable; reportable only when in aqueous solution) | — | — | — | — | — | |
| Propylene | — | — | — | — | — | |
| Nickel compounds | 220,061 | 61 | — | 220,000 | — | ♦ Carcinogen |
| Methanol | 81,108 | 108 | — | 81,000 | — | |
| Chromium compounds (except for chromite ore mined in the Transvaal Region) | 62,000 | — | — | 62,000 | — | |
| Copper compounds | 51,000 | — | — | 51,000 | — | |
| Lead compounds | 2,558 | 0 | — | 2,558 | — | |
| Mercury compounds | 27 | — | — | 27 | — |
2019
| Chemical | Total (lbs) | Air | Water | Land | Off-Site | |
|---|---|---|---|---|---|---|
| Propylene | — | — | — | — | — | |
| Methanol | 80,780 | 107 | — | 80,673 | — | |
| Chromium compounds (except for chromite ore mined in the Transvaal Region) | 66,000 | — | — | 66,000 | — |
2018
| Chemical | Total (lbs) | Air | Water | Land | Off-Site | |
|---|---|---|---|---|---|---|
| Propylene | — | — | — | — | — | |
| Nickel compounds | 161,119 | 59 | — | 161,060 | — | ♦ Carcinogen |
| Methanol | 95,426 | 119 | — | 95,307 | — | |
| Chromium compounds (except for chromite ore mined in the Transvaal Region) | 55,482 | — | — | 55,482 | — | |
| Copper compounds | 29,046 | — | — | 29,046 | — | |
| Lead compounds | 3,565 | 1 | — | 3,564 | — | |
| Nitrate compounds (water dissociable; reportable only when in aqueous solution) | 877 | — | — | 877 | — | |
| Mercury compounds | 3 | — | — | 3 | — |
2017
| Chemical | Total (lbs) | Air | Water | Land | Off-Site | |
|---|---|---|---|---|---|---|
| Propylene | — | — | — | — | — | |
| Nickel compounds | 163,517 | — | — | 163,517 | — | ♦ Carcinogen |
| Methanol | 83,708 | 134 | — | 83,574 | — | |
| Chromium compounds (except for chromite ore mined in the Transvaal Region) | 39,855 | — | — | 39,855 | — | |
| Copper compounds | 31,196 | 5 | — | 31,191 | — | |
| Lead compounds | 5,971 | 2 | — | 5,969 | — | |
| Nitrate compounds (water dissociable; reportable only when in aqueous solution) | 2,043 | — | — | 2,043 | — | |
| Mercury compounds | 13 | — | — | 13 | — |
2016
| Chemical | Total (lbs) | Air | Water | Land | Off-Site | |
|---|---|---|---|---|---|---|
| Propylene | — | — | — | — | — | |
| Mercury compounds | — | — | — | — | — | |
| Nickel compounds | 165,576 | 58 | — | 165,518 | — | ♦ Carcinogen |
| Methanol | 87,728 | 134 | — | 87,594 | — | |
| Chromium compounds (except for chromite ore mined in the Transvaal Region) | 42,359 | 2 | — | 42,357 | — | |
| Copper compounds | 32,419 | — | — | 32,419 | — | |
| Lead compounds | 2,130 | 0 | — | 2,130 | — | |
| Nitrate compounds (water dissociable; reportable only when in aqueous solution) | 2,042 | — | — | 2,042 | — |
2015
| Chemical | Total (lbs) | Air | Water | Land | Off-Site | |
|---|---|---|---|---|---|---|
| Mercury compounds | — | — | — | — | — | |
| Propylene | — | — | — | — | — | |
| Nickel compounds | 154,658 | 60 | — | 154,598 | — | ♦ Carcinogen |
| Methanol | 96,314 | 132 | — | 96,182 | — | |
| Chromium compounds (except for chromite ore mined in the Transvaal Region) | 44,416 | 18 | — | 44,398 | — | |
| Copper compounds | 31,244 | 6 | — | 31,238 | — | |
| Lead compounds | 2,282 | 0 | — | 2,281 | — | |
| Nitrate compounds (water dissociable; reportable only when in aqueous solution) | 528 | — | — | 528 | — |
Waste Management & Recycling
How this facility manages toxic chemicals beyond direct releases — through recycling, energy recovery, and on-site or off-site treatment. Data from the most recent TRI reporting year. Quantities in pounds.
| Chemical | Released | Recycled | Energy Recovery | Treated |
|---|---|---|---|---|
| Nitrate compounds (water dissociable; reportable only when in aqueous solution) | — | — | — | 37,674 |
Compliance Violations
Individual permit violations recorded by the EPA across air, water, and hazardous waste programs. Open violations are unresolved as of the most recent ECHO data update.
| Program | Type | Violation Date | Return to Compliance | Status |
|---|---|---|---|---|
| cwa | Schedule Event unachieved and not reported | Jan 12, 2026 | Feb 12, 2026 | Resolved |
| cwa | Schedule Event unachieved and not reported | Feb 11, 2025 | Mar 14, 2025 | Resolved |
| cwa | Schedule Event unachieved and not reported | Feb 11, 2025 | Mar 14, 2025 | Resolved |
| cwa | Schedule Event reported late | Feb 11, 2025 | — | Open |
| cwa | Schedule Event unachieved and not reported | Feb 11, 2025 | Dec 23, 2025 | Resolved |
| cwa | Schedule Event unachieved but reported | Feb 11, 2025 | Dec 23, 2025 | Resolved |
| cwa | Schedule Event unachieved and not reported | Feb 11, 2025 | Mar 14, 2025 | Resolved |
| cwa | Schedule Event achieved late but reported | Feb 11, 2025 | — | Open |
Discharge Limit Exceedances
Instances where this facility's reported discharge monitoring results exceeded its permitted limits under the Clean Water Act. Exceedance percentage shows how far over the permit limit the discharge was.
| Pollutant | Violation | Reported | Limit | Exceedance | Period | Status |
|---|---|---|---|---|---|---|
| Mercury, total recoverable | DMR, Limited - Numeric Violation | 0.00 mg/L | 0.00 | +20% | Jan 2026 | Open |
| Mercury, total recoverable | DMR, Limited - Numeric Violation | 0.00 mg/L | 0.00 | +20% | Jan 2026 | Open |
| Lead, total recoverable | DMR, Limited - Numeric Violation | 0.00 mg/L | 0.00 | +127% | Nov 2023 | Open |
| Lead, total recoverable | DMR, Limited - Numeric Violation | 0.00 kg/d | 0.00 | +40% | Nov 2023 | Open |
| Lead, total recoverable | DMR, Limited - Numeric Violation | 0.00 mg/L | 0.00 | +127% | Nov 2023 | Open |
| Nitrogen, inorganic total | DMR, Limited - Numeric Violation | 8.08 mg/L | 7.50 | +8% | Sep 2015 | Open |
| Nitrogen, inorganic total | DMR, Limited - Numeric Violation | 27.69 mg/L | 7.50 | +269% | Sep 2015 | Open |
| Nitrogen, inorganic total | DMR, Limited - Numeric Violation | 26.66 mg/L | 7.50 | +255% | Sep 2015 | Open |
| Nitrogen, inorganic total | DMR, Limited - Numeric Violation | 28.80 mg/L | 10.00 | +188% | Jun 2015 | Resolved |
| Nitrogen, inorganic total | DMR, Limited - Numeric Violation | 19.80 mg/L | 10.00 | +98% | Jun 2015 | Resolved |
| Nitrogen, inorganic total | DMR, Limited - Numeric Violation | 28.39 mg/L | 10.00 | +184% | Jun 2015 | Resolved |
| Nitrogen, inorganic total | DMR, Limited - Numeric Violation | 50.49 mg/L | 10.00 | +405% | Mar 2015 | Resolved |
| Nitrogen, inorganic total | DMR, Limited - Numeric Violation | 16.36 mg/L | 10.00 | +64% | Mar 2015 | Resolved |
| Nitrogen, inorganic total | DMR, Limited - Numeric Violation | 35.92 mg/L | 10.00 | +259% | Mar 2015 | Resolved |
Enforcement Actions
Formal enforcement cases brought by the EPA or state agencies, including administrative orders and civil penalties assessed. Penalty amounts reflect what was formally assessed, not necessarily what was collected.
State Administrative Order of Consent
Clean Water Act
· Case MT-FID 1922 · Aug 6, 2010
$3,600
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