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Montana Sulphur and Chemical Co

Industrial Inorganic Chemicals, Billings, Montana. NPDES permit MT0000230 expired Dec 31, 2025; its limits still apply. Last 12 months: no values over a limit, 2 required values missing, 1 of 17 reports late. Source: EPA ECHO, Oct 22, 2026.

Reports due
About 28 days after each period: form A monthly (20 values), form Q quarterly (5 values), form Q2 quarterly (2 values)
Last report on file
August 2026
Oct 2024 – Sep 2025
0 values over a limit, 2 required values missing, 1 of 20 reports late

Limits in force (27)

ParameterStatisticLimitMonths
Temperature, water deg. fahrenheitdaily maximum≤ 95 deg Fall year
Flow ratemonthly averagereport only (gal/min)all year
Flow ratedaily maximumreport only (gal/min)all year
pHdaily minimum≥ 6 SUall year
pHdaily maximum≤ 9 SUall year
Solids, total suspendedaveragereport only (mg/L)all year
Solids, total suspendeddaily maximumreport only (mg/L)all year
Solids, total suspendeddaily maximum≤ 30 mg/Lall year
Solids, total suspendedaveragereport only (mg/L)all year
Solids, total suspendeddaily maximumreport only (mg/L)all year
Oil & Greasedaily maximum≤ 10 mg/Lall year
Nitrogen, total [as N]monthly averagereport only (mg/L)Jul–Oct
Nitrite + Nitrate total [as N]monthly averagereport only (mg/L)Jul–Oct
Phosphorus, total [as P]monthly averagereport only (mg/L)Jul–Oct
Sulfate, total [as SO4]valuereport only (ug/L)all year
Iron, total recoverablemonthly averagereport only (ug/L)all year
Iron, total recoverabledaily maximumreport only (ug/L)all year
Aluminum, dissolved [as Al]monthly averagereport only (ug/L)all year
Cadmium, total recoverablemonthly averagereport only (ug/L)all year
Lead, total recoverablemonthly averagereport only (ug/L)all year
Nitrogen, total Kjeldahlmonthly averagereport only (mg/L)Jul–Oct
Chlorine, total residualmonthly average≤ 11 mg/Lall year
Chlorine, total residualdaily maximum≤ 19 mg/Lall year
Hydrogen sulfidevaluereport only (ug/L)all year
Oil and grease visualvaluereport only (Y=0;N=1)all year
Pass/Fail Static Renewal 48Hr Acute Ceriodaphnia dubiavaluereport only (pass=0;fail=1)all year
Pass/Fail Static Renewal 96Hr Acute Pimephales Promelasvaluereport only (pass=0;fail=1)all year

How strict are these limits?

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

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

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On EPA ECHO: Facility report · DMR history

Your permit document is the final word. As JSON: /api/v1/permits/MT0000230 · MCP: https://passage-data.com/mcp