MAC INDUSTRIAL HOLDINGS LLC
NPDES ID: INP000634
E — SNC: Effluent violation (monthly average limit)
The facility discharged more of a pollutant than its permit allows, based on a monthly average.
This quarter: 5 single-event violations.
Violations
March 31, 2026
Zinc, total recoverable
75% over limit
Discharged 8.73 mg/L against a permitted limit of 5 mg/L (MO AVG)
DMR, Limited - Numeric Violation
December 31, 2025
Zinc, total recoverable
300% over limit
Discharged 20 mg/L against a permitted limit of 5 mg/L (MO AVG)
DMR, Limited - Numeric Violation
Zinc, total recoverable
100% over limit
Discharged 20 mg/L against a permitted limit of 10 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
June 30, 2025
Zinc, total recoverable
84% over limit
Discharged 9.2 mg/L against a permitted limit of 5 mg/L (MO AVG)
DMR, Limited - Numeric Violation
May 31, 2025
pH
0% over limit
Discharged 6.9 SU against a permitted limit of 5 SU (DAILY MN)
DMR, Limited - Overdue
Flow, in conduit or thru treatment plant
0% over limit
Discharged 0.0067 MGD against a permitted limit of 0 MGD (DAILY MX)
DMR, Monitor Only - Overdue
Flow, in conduit or thru treatment plant
0% over limit
Discharged 0.002 MGD against a permitted limit of 0 MGD (MO AVG)
DMR, Monitor Only - Overdue
pH
0% over limit
Discharged 7.1 SU against a permitted limit of 10 SU (DAILY MX)
DMR, Limited - Overdue
April 30, 2025
Flow, in conduit or thru treatment plant
0% over limit
Discharged 0.0079 MGD against a permitted limit of 0 MGD (DAILY MX)
DMR, Monitor Only - Overdue
Flow, in conduit or thru treatment plant
0% over limit
Discharged 0.0026 MGD against a permitted limit of 0 MGD (MO AVG)
DMR, Monitor Only - Overdue
pH
0% over limit
Discharged 7 SU against a permitted limit of 5 SU (DAILY MN)
DMR, Limited - Overdue
pH
0% over limit
Discharged 7 SU against a permitted limit of 10 SU (DAILY MX)
DMR, Limited - Overdue
July 31, 2024
Flow, in conduit or thru treatment plant
0% over limit
Discharged 0.00976607 MGD against a permitted limit of 0 MGD (DAILY MX)
DMR, Monitor Only - Overdue
pH
0% over limit
Discharged 8.68 SU against a permitted limit of 10 SU (DAILY MX)
DMR, Limited - Overdue
Flow, in conduit or thru treatment plant
0% over limit
Discharged 0.00109237 MGD against a permitted limit of 0 MGD (MO AVG)
DMR, Monitor Only - Overdue
pH
0% over limit
Discharged 6.96 SU against a permitted limit of 5 SU (DAILY MN)
DMR, Limited - Overdue
First flagged
April 14, 2026 (3 months ago)
Last confirmed
July 13, 2026 (23 days ago)