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Main Iron Works LLC

Ship Building And Repairing, Houma, Louisiana. NPDES permit LA0104868, in force until Mar 31, 2027. Last 12 months: over a limit 18 times (last June 2026). Source: EPA ECHO, Oct 22, 2026.

Reports due
About 28 days after each period: outfall 001 form Q quarterly (12 values), outfall 003 form Q quarterly (12 values), outfall 008 form Q quarterly (6 values), outfall 009 form Q quarterly (6 values), outfall 010 form Q quarterly (6 values), outfall 012 form Q quarterly (12 values), and 3 more forms
Renewal application due
Oct 2, 2026 · 180 days before expiry; your permit may set another date
Last report on file
June 2026
Oct 2024 – Sep 2025
13 values over a limit, 0 required values missing, 0 of 36 reports late

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

All 18 values over a limit
Period endingOutfallParameterReportedLimitOver by
December 2025001BOD, carbonaceous [5 day, 20 C], daily maximum64 mg/L≤ 45 mg/L42%
December 2025001BOD, carbonaceous [5 day, 20 C], monthly average64 mg/L≤ 30 mg/L113%
December 2025001Coliform, fecal general, daily maximum> 2419 #/100mL≤ 400 #/100mL—
December 2025001Coliform, fecal general, monthly geometric mean> 2419 #/100mL≤ 200 #/100mL—
December 2025001Nitrogen, ammonia total [as N], daily maximum84.5 mg/L≤ 15 mg/L463%
December 202502ANitrogen, ammonia total [as N], daily maximum20.9 mg/L≤ 15 mg/L39%
December 202502BNitrogen, ammonia total [as N], daily maximum64 mg/L≤ 15 mg/L327%
March 2026001BOD, carbonaceous [5 day, 20 C], daily maximum64 mg/L≤ 45 mg/L42%
March 2026001BOD, carbonaceous [5 day, 20 C], monthly average64 mg/L≤ 30 mg/L113%
March 2026001Coliform, fecal general, daily maximum2419 #/100mL≤ 400 #/100mL505%
March 2026001Coliform, fecal general, monthly geometric mean2419 #/100mL≤ 200 #/100mL1110%
March 2026001Nitrogen, ammonia total [as N], daily maximum84.5 mg/L≤ 15 mg/L463%
March 202602ANitrogen, ammonia total [as N], daily maximum20.9 mg/L≤ 15 mg/L39%
March 202602BNitrogen, ammonia total [as N], daily maximum64 mg/L≤ 15 mg/L327%
June 202602ANitrogen, ammonia total [as N], daily maximum24.1 mg/L≤ 15 mg/L61%
June 202602ANitrogen, organic total [as N], daily maximum10.6 mg/L≤ 7.5 mg/L41%
June 202602ASolids, total suspended, daily maximum171 mg/L≤ 45 mg/L280%
June 202602ASolids, total suspended, monthly average171 mg/L≤ 30 mg/L470%

Limits in force (90)

ParameterStatisticLimitMonthsOutfall
pHminimum≥ 6 SUall year001
pHmaximum≤ 9 SUall year001
Solids, total suspendedmonthly average≤ 30 mg/Lall year001
Solids, total suspendeddaily maximum≤ 45 mg/Lall year001
Nitrogen, organic total [as N]daily maximum≤ 7.5 mg/Lall year001
Nitrogen, ammonia total [as N]daily maximum≤ 15 mg/Lall year001
Flow, in conduit or thru treatment plantmonthly averagereport only (MGD)all year001
Flow, in conduit or thru treatment plantdaily maximumreport only (MGD)all year001
Coliform, fecal generalmonthly geometric mean≤ 200 #/100mLall year001
Coliform, fecal generaldaily maximum≤ 400 #/100mLall year001
BOD, carbonaceous [5 day, 20 C]monthly average≤ 30 mg/Lall year001
BOD, carbonaceous [5 day, 20 C]daily maximum≤ 45 mg/Lall year001
pHminimum≥ 6 SUall year003
pHmaximum≤ 9 SUall year003
Solids, total suspendedmonthly average≤ 30 mg/Lall year003
Solids, total suspendeddaily maximum≤ 45 mg/Lall year003
Nitrogen, organic total [as N]daily maximum≤ 7.5 mg/Lall year003
Nitrogen, ammonia total [as N]daily maximum≤ 15 mg/Lall year003
Flow, in conduit or thru treatment plantmonthly averagereport only (MGD)all year003
Flow, in conduit or thru treatment plantdaily maximumreport only (MGD)all year003
Coliform, fecal generalmonthly geometric mean≤ 200 #/100mLall year003
Coliform, fecal generaldaily maximum≤ 400 #/100mLall year003
BOD, carbonaceous [5 day, 20 C]monthly average≤ 30 mg/Lall year003
BOD, carbonaceous [5 day, 20 C]daily maximum≤ 45 mg/Lall year003
pHminimum≥ 6 SUall year008
pHmaximum≤ 9 SUall year008
Oil & Greasedaily maximum≤ 15 mg/Lall year008
Carbon, tot organic [TOC]daily maximum≤ 50 mg/Lall year008
Flow, in conduit or thru treatment plantmonthly averagereport only (MGD)all year008
Flow, in conduit or thru treatment plantdaily maximumreport only (MGD)all year008
pHminimum≥ 6 SUall year009
pHmaximum≤ 9 SUall year009
Oil & Greasedaily maximum≤ 15 mg/Lall year009
Carbon, tot organic [TOC]daily maximum≤ 50 mg/Lall year009
Flow, in conduit or thru treatment plantmonthly averagereport only (MGD)all year009
Flow, in conduit or thru treatment plantdaily maximumreport only (MGD)all year009
pHminimum≥ 6 SUall year010
pHmaximum≤ 9 SUall year010
Oil & Greasedaily maximum≤ 15 mg/Lall year010
Carbon, tot organic [TOC]daily maximum≤ 50 mg/Lall year010
Flow, in conduit or thru treatment plantmonthly averagereport only (MGD)all year010
Flow, in conduit or thru treatment plantdaily maximumreport only (MGD)all year010
pHminimum≥ 6 SUall year012
pHmaximum≤ 9 SUall year012
Solids, total suspendedmonthly average≤ 30 mg/Lall year012
Solids, total suspendeddaily maximum≤ 45 mg/Lall year012
Nitrogen, organic total [as N]daily maximum≤ 7.5 mg/Lall year012
Nitrogen, ammonia total [as N]daily maximum≤ 15 mg/Lall year012
Flow, in conduit or thru treatment plantmonthly averagereport only (MGD)all year012
Flow, in conduit or thru treatment plantdaily maximumreport only (MGD)all year012
Coliform, fecal generalmonthly geometric mean≤ 200 #/100mLall year012
Coliform, fecal generaldaily maximum≤ 400 #/100mLall year012
BOD, carbonaceous [5 day, 20 C]monthly average≤ 30 mg/Lall year012
BOD, carbonaceous [5 day, 20 C]daily maximum≤ 45 mg/Lall year012
pHminimum≥ 6 SUall year013
pHmaximum≤ 9 SUall year013
Solids, total suspendedmonthly average≤ 30 mg/Lall year013
Solids, total suspendeddaily maximum≤ 45 mg/Lall year013
Nitrogen, organic total [as N]daily maximum≤ 7.5 mg/Lall year013
Nitrogen, ammonia total [as N]daily maximum≤ 15 mg/Lall year013
Flow, in conduit or thru treatment plantmonthly averagereport only (MGD)all year013
Flow, in conduit or thru treatment plantdaily maximumreport only (MGD)all year013
Coliform, fecal generalmonthly geometric mean≤ 200 #/100mLall year013
Coliform, fecal generaldaily maximum≤ 400 #/100mLall year013
BOD, carbonaceous [5 day, 20 C]monthly average≤ 30 mg/Lall year013
BOD, carbonaceous [5 day, 20 C]daily maximum≤ 45 mg/Lall year013
pHminimum≥ 6 SUall year02A
pHmaximum≤ 9 SUall year02A
Solids, total suspendedmonthly average≤ 30 mg/Lall year02A
Solids, total suspendeddaily maximum≤ 45 mg/Lall year02A
Nitrogen, organic total [as N]daily maximum≤ 7.5 mg/Lall year02A
Nitrogen, ammonia total [as N]daily maximum≤ 15 mg/Lall year02A
Flow, in conduit or thru treatment plantmonthly averagereport only (MGD)all year02A
Flow, in conduit or thru treatment plantdaily maximumreport only (MGD)all year02A
Coliform, fecal generalmonthly geometric mean≤ 200 #/100mLall year02A
Coliform, fecal generaldaily maximum≤ 400 #/100mLall year02A
BOD, carbonaceous [5 day, 20 C]monthly average≤ 30 mg/Lall year02A
BOD, carbonaceous [5 day, 20 C]daily maximum≤ 45 mg/Lall year02A
pHminimum≥ 6 SUall year02B
pHmaximum≤ 9 SUall year02B
Solids, total suspendedmonthly average≤ 30 mg/Lall year02B
Solids, total suspendeddaily maximum≤ 45 mg/Lall year02B
Nitrogen, organic total [as N]daily maximum≤ 7.5 mg/Lall year02B
Nitrogen, ammonia total [as N]daily maximum≤ 15 mg/Lall year02B
Flow, in conduit or thru treatment plantmonthly averagereport only (MGD)all year02B
Flow, in conduit or thru treatment plantdaily maximumreport only (MGD)all year02B
Coliform, fecal generalmonthly geometric mean≤ 200 #/100mLall year02B
Coliform, fecal generaldaily maximum≤ 400 #/100mLall year02B
BOD, carbonaceous [5 day, 20 C]monthly average≤ 30 mg/Lall year02B
BOD, carbonaceous [5 day, 20 C]daily maximum≤ 45 mg/Lall year02B

How strict are these limits?

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

Same industry: the 15 Transportation Equipment permits in Louisiana.

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On EPA ECHO: Facility report · DMR history

Your permit document is the final word. As JSON: /api/v1/permits/LA0104868 · MCP: https://passage-data.com/mcp