Clean Water Act discharge permit · NPDES MT0000477
PAR MONTANA LLC, Billings, MT: NPDES MT0000477 discharge permit, effluent exceedances, inspections, penalties
- Administratively continuedPermit status
- MajorDischarger class
- 16Pollutants under a numeric limit
- 7Pollutants with an effluent exceedance
PAR MONTANA LLC, held by EXXONMOBIL REFINING AND SUPPLY CO, holds NPDES permit MT0000477, which discharges to Yellowstone River. EPA’s file records it issued October 20, 2003 and expiring October 31, 2008. The status and dates are as EPA’s permit file stood when Velarion loaded it (September 14, 2026); EPA’s free Detailed Facility Report on ECHO carries the permit’s current standing.
Identity
| Facility as filed | PAR MONTANA LLC |
|---|---|
| Permittee as filed | EXXONMOBIL REFINING AND SUPPLY CO |
| NPDES ID | MT0000477 |
| Permit status | Administratively continued (past its expiration date and still in force until reissued) |
| Permit type | Individual permit |
| Discharger class | Major discharger |
| Facility type | Not a publicly owned treatment works |
| Issued | October 20, 2003 |
| Expiration date | October 31, 2008 |
| Issuing agency | MONTANA DEQ |
| Address | Billings, MT 59101 |
| Receiving water | YELLOWSTONE RIVER |
| Receiving water impaired | 303(D) Listed |
| Subwatershed | Yellowstone River-Sevenmile Creek (HUC 100700070403) |
Cited to the EPA ICIS-NPDES permit file (ECHO download).
Effluent limits and exceedances
- 24Pollutants on file
- 16Under a numeric limit
- 23With a violation of any kind
- 7With an effluent exceedance
An effluent exceedance is a discharge monitoring report value over the permit’s numeric limit (EPA’s violation code E90). A violation of any kind also counts a report not filed. Each row is EPA’s own count for that pollutant.
| Pollutant or measure | Limits | Violations, any kind | Effluent exceedances | Latest exceedance | Largest exceedance, as filed |
|---|---|---|---|---|---|
| Sulfide, total [as S] | 4 | 32 | 14 | November 30, 2024 | 276% over the limit |
| Pass/Fail Static Renewal 96Hr Acute Pimephales Promelas | 3 | 12 | 11 | December 31, 2025 | |
| pH | 4 | 17 | 8 | September 30, 2012 | |
| BOD, 5-day, 20 deg. C | 4 | 19 | 5 | November 30, 2017 | 35% over the limit |
| Phenols | 4 | 20 | 3 | December 31, 2023 | 84% over the limit |
| Nitrogen, ammonia total [as N] | 4 | 21 | 1 | January 31, 2003 | 749% over the limit |
| Oxidants, total residual | 2 | 3 | 1 | February 28, 1995 | 7% over the limit |
| Solids, total suspended | 12 | 30 | 0 | ||
| Oil & Grease | 6 | 18 | 0 | ||
| Oxygen demand, chem. [high level] [COD] | 4 | 18 | 0 | ||
| Chromium, hexavalent [as Cr] | 4 | 16 | 0 | ||
| Chromium, total [as Cr] | 4 | 16 | 0 | ||
| Flow rate | 4 | 8 | 0 | ||
| Temperature, water deg. fahrenheit | 3 | 7 | 0 | ||
| Oil and grease visual | 2 | 4 | 0 | ||
| Oxygen, dissolved [DO] | 0 | 4 | 0 | ||
| Nitrogen, total [as N] | 0 | 4 | 0 | ||
| Nitrogen, Kjeldahl, total [as N] | 0 | 4 | 0 | ||
| Nitrite + Nitrate total [as N] | 0 | 4 | 0 | ||
| Phosphorus, total [as P] | 0 | 4 | 0 | ||
| Arsenic, total recoverable | 0 | 4 | 0 | ||
| Phenolics, total recoverable | 0 | 4 | 0 | ||
| Sulfide-hydrogen sulfide [undissociated] | 0 | 3 | 0 | ||
| Pass/Fail Static Renewal 48Hr Acute Ceriodaphnia dubia | 2 | 0 | 0 |
Cited to the EPA ICIS-NPDES limits and effluent violations files (ECHO download); up to 60 rows shown, most exceedances first.
Inspections, violations and enforcement
- 4Single-event violations
| Date | What EPA recorded | Agency |
|---|---|---|
| February 10, 2026 | Reporting Violations - Improper/ Incorrect Reporting | ST6 |
| November 30, 2023 | Monitoring Violations - Invalid/Unrepresentative Sample | ST6 |
| November 30, 2023 | Reporting Violations - Improper/ Incorrect Reporting | ST6 |
| November 29, 2017 | Reporting Violations - Improper/ Incorrect Reporting | ST6 |
Velarion’s copy of EPA’s ICIS-NPDES files does not yet include the inspections, formal enforcement actions and informal enforcement actions files, so this page shows none of them. EPA’s free Detailed Facility Report on ECHO lists this permit’s inspections, enforcement actions and penalties.
Cited to the EPA ICIS-NPDES violation, inspection and enforcement files (ECHO download); up to 50 rows of each shown, newest first.
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EPA publishes a free Detailed Facility Report for every permit on ECHO: its compliance status quarter by quarter, its inspections, and its enforcement actions and penalties. EPA also sends free notices of new inspections and enforcement actions through ECHO Notify; enter NPDES ID MT0000477 there.
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Figures from EPA’s ICIS-NPDES download, loaded September 14, 2026.