Passage Data · Check a report · Use it from your AI

Hemlock Semiconductor Operations LLC

Minerals, Ground Or Treated, Hemlock, Michigan. NPDES permit MI0027375, in force until Oct 1, 2028. Last 12 months: over a limit once (last June 2026). Source: EPA ECHO, Oct 22, 2026.

Reports due
About 21 days after each period: form A monthly (31 values)
Renewal application due
Apr 4, 2028 · 180 days before expiry; your permit may set another date
Last report on file
September 2026
Oct 2024 – Sep 2025
0 values over a limit, 0 required values missing, 0 of 12 reports late

Last 12 months (Oct 1, 2025 – Sep 30, 2026)

Period endingParameterReportedLimitOver by
June 2026Chlorine, total residual, daily maximum40≤ 38 ug/L5%

Limits in force (44)

ParameterStatisticLimitMonths
Temperature, water deg. fahrenheitdaily maximumreport only (deg F)all year
Thermal Dischargemonthly averagereport only (MBTU/hr)all year
Thermal Dischargedaily maximumreport only (MBTU/hr)all year
Oxygen, dissolved [DO]daily minimum≥ 3 mg/LMar, Apr
Oxygen, dissolved [DO]daily minimum≥ 5 mg/LJan, Feb, May, Jun, Jul, Aug, Sep, Oct, Nov, Dec
pHdaily minimum≥ 6.5 SUall year
pHdaily maximum≤ 9 SUall year
Solids, total suspendedmonthly average≤ 20 mg/Lall year
Solids, total suspendeddaily maximum≤ 30 mg/Lall year
Solids, total suspendedmonthly average≤ 250 lb/dall year
Solids, total suspendeddaily maximum≤ 380 lb/dall year
Phosphorus, total [as P]monthly average≤ .8 mg/Lall year
Phosphorus, total [as P]daily maximumreport only (mg/L)all year
Phosphorus, total [as P]monthly average≤ 10 lb/dall year
Phosphorus, total [as P]daily maximumreport only (lb/d)all year
Chloride [as Cl]daily maximumreport only (mg/L)all year
Sulfate, total [as SO4]daily maximumreport only (mg/L)all year
Copper, total [as Cu]daily maximumreport only (ug/L)all year
Flow, in conduit or thru treatment plantmonthly averagereport only (MGD)all year
Flow, in conduit or thru treatment plantdaily maximumreport only (MGD)all year
Chlorine, total residualdaily maximum≤ 38 ug/Lall year
Solids, total dissolvedmonthly average≤ 500 mg/LJan, Feb
Solids, total dissolvedmonthly average≤ 500 mg/LMay, Jun
Solids, total dissolvedmonthly average≤ 500 mg/LJul–Dec
Solids, total dissolvedmonthly average≤ 520 mg/LMar, Apr
Solids, total dissolveddaily maximum≤ 760 mg/LJan, Feb
Solids, total dissolveddaily maximum≤ 760 mg/LMay, Jun
Solids, total dissolveddaily maximum≤ 750 mg/LJul–Dec
Solids, total dissolveddaily maximum≤ 910 mg/LMar, Apr
Solids, total dissolvedmonthly average≤ 6300 lb/dJan, Feb
Solids, total dissolvedmonthly average≤ 6300 lb/dMay, Jun
Solids, total dissolvedmonthly average≤ 6300 lb/dJul–Dec
Solids, total dissolvedmonthly average≤ 6500 lb/dMar, Apr
Solids, total dissolveddaily maximum≤ 9500 lb/dJan, Feb
Solids, total dissolveddaily maximum≤ 9500 lb/dMay, Jun
Solids, total dissolveddaily maximum≤ 9400 lb/dJul–Dec
Solids, total dissolveddaily maximum≤ 11000 lb/dMar, Apr
Mercury, total [as Hg]monthly averagereport only (ng/L)all year
Mercury, total [as Hg]daily maximumreport only (ng/L)all year
Mercury, total [as Hg]monthly averagereport only (lb/d)all year
Mercury, total [as Hg]daily maximumreport only (lb/d)all year
Mercury, total [as Hg]12-month average≤ 4 ng/Lall year
Mercury, total [as Hg]12-month average≤ .00005 lb/dall year
Outfall observation,visual, y/n responsevaluereport only (N=0;Y=1)all year

New limits from Oct 1, 2027

ParameterNew limitNew or tighterMedian, last 12 months× new limit
Thermal Discharge, monthly average3 MBTU/hrnew0.3105 MBTU/hr (12 values)0.103×

How strict are these limits?

Cited limits by parameter: Michigan's rules and the federal ones.

Same industry: the 7 Stone, Clay, Glass and Concrete Products permits in Michigan.

Check this month's numbers Email me before each report is due

· Save this facility as a site · Superfund sites nearby · Your permits on one board

On EPA ECHO: Facility report · DMR history

Your permit document is the final word. As JSON: /api/v1/permits/MI0027375 · MCP: https://passage-data.com/mcp