Clean Water Act discharge permit · NPDES MI0027375
HSC, Hemlock, MI: NPDES MI0027375 discharge permit, effluent exceedances, inspections, penalties
- Administratively continuedPermit status
- MinorDischarger class
- 11Pollutants under a numeric limit
- 6Pollutants with an effluent exceedance
HSC, held by Hemlock Semiconductor Operations LLC, holds NPDES permit MI0027375, which discharges to Mcclellan Run. EPA’s file records it issued February 25, 2019 and expiring October 1, 2023. The status and dates are as EPA’s permit file stood when Velarion loaded it (September 15, 2026); EPA’s free Detailed Facility Report on ECHO carries the permit’s current standing.
Identity
| Facility as filed | HSC |
|---|---|
| Permittee as filed | Hemlock Semiconductor Operations LLC |
| NPDES ID | MI0027375 |
| Permit status | Administratively continued (past its expiration date and still in force until reissued) |
| Permit type | Individual permit |
| Discharger class | Minor discharger |
| Facility type | Not a publicly owned treatment works |
| Issued | February 25, 2019 |
| Expiration date | October 1, 2023 |
| Issuing agency | State |
| Address | Hemlock, MI 48626 |
| Receiving water | McClellan Run |
| Subwatershed | Swan Creek (HUC 040802030407) |
| Other EPA IDs (FRS) | RCRA handler MID095395216; ICIS-AIR source MI00000000000B2644 |
Cited to the EPA ICIS-NPDES permit file (ECHO download); cross-program IDs from EPA’s FRS facility-registry crosswalk.
Effluent limits and exceedances
- 11Pollutants on file
- 11Under a numeric limit
- 11With a violation of any kind
- 6With 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 |
|---|---|---|---|---|---|
| Copper, total [as Cu] | 4 | 37 | 13 | February 28, 2022 | 36% over the limit |
| Chlorine, total residual | 1 | 42 | 11 | June 30, 2026 | 1,242% over the limit |
| Solids, total dissolved | 12 | 289 | 3 | May 31, 2009 | 14% over the limit |
| pH | 2 | 65 | 3 | February 28, 2006 | |
| Solids, total suspended | 4 | 121 | 1 | March 31, 2006 | 17% over the limit |
| Oxygen, dissolved [DO] | 2 | 72 | 1 | June 30, 2002 | 10% over the limit |
| Mercury, total [as Hg] | 6 | 62 | 0 | ||
| Phosphorus, total [as P] | 4 | 60 | 0 | ||
| Flow, in conduit or thru treatment plant | 2 | 60 | 0 | ||
| Outfall observation,visual, y/n response | 1 | 35 | 0 | ||
| Temperature, water deg. fahrenheit | 1 | 31 | 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 |
|---|---|---|
| July 9, 2021 | WW Storm Water Non-Construction - Failure to develop any or adequate SWPPP/SWMP | ST6 |
| March 4, 2020 | Permit Violations - Discharge Without a Valid Permit | ST6 |
| February 28, 2020 | Permit Violations - Discharge Without a Valid Permit | ST6 |
| February 14, 2020 | Permit Violations - Discharge Without a Valid Permit | ST6 |
Velarion’s copy of EPA’s ICIS-NPDES files does not 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.
Watch this permit
One permit holder, $99/month. Watch the register for one permit holder and the places and receiving waters tied to its permits. Choose “One permit holder” and enter this permit’s NPDES ID, MI0027375.
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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 MI0027375 there.
Nearby on the register
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- Every permit record in Michigan, A to Z
Figures from EPA’s ICIS-NPDES download, loaded September 15, 2026.