NOGALES INTERNATIONAL WASTEWATER TREATMENT PLANT
NPDES ID: AZ0025607
X — SNC: Effluent violation (non-monthly average limit)
The facility discharged more of a pollutant than its permit allows, measured over a period other than a monthly average.
Violations
March 31, 2026
Copper, total recoverable
36% over limit
Discharged 0.14016 mg/L against a permitted limit of 0.10296 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
Chromium, total recoverable
39% over limit
Discharged 0.01896 mg/L against a permitted limit of 0.01368 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
TU Static Renewal 7-Day Chronic Ceriodaphnia dubia
113% over limit
Discharged 2.125 toxic against a permitted limit of 1 toxic (MO AVG)
DMR, Limited - Numeric Violation
Cadmium, total recoverable
64% over limit
Discharged 0.00552 mg/L against a permitted limit of 0.00336 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
TU Static 4 Day Chronic Raphidocelis subcapitata (formerly Selenastrum capricornutum)
100% over limit
Discharged 2 toxic against a permitted limit of 1 toxic (MO MED)
DMR, Limited - Numeric Violation
Zinc, total recoverable
65% over limit
Discharged 0.36023999 mg/L against a permitted limit of 0.21768 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
TU Static 4 Day Chronic Raphidocelis subcapitata (formerly Selenastrum capricornutum)
25% over limit
Discharged 2 toxic against a permitted limit of 1.6 toxic (DAILY MX)
DMR, Limited - Numeric Violation
TU Static Renewal 7-Day Chronic Ceriodaphnia dubia
400% over limit
Discharged 8 toxic against a permitted limit of 1.6 toxic (DAILY MX)
DMR, Limited - Numeric Violation
December 31, 2025
Lead, total recoverable
67% over limit
Discharged 0.02004 mg/L against a permitted limit of 0.012 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
TU Static Renewal 7-Day Chronic Ceriodaphnia dubia
50% over limit
Discharged 1.5 toxic against a permitted limit of 1 toxic (MO AVG)
DMR, Limited - Numeric Violation
Zinc, total recoverable
205% over limit
Discharged 0.66287999 mg/L against a permitted limit of 0.21768 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
Chromium, total recoverable
141% over limit
Discharged 0.033 mg/L against a permitted limit of 0.01368 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
Silver total recoverable
60% over limit
Discharged 0.024 mg/L against a permitted limit of 0.015 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
Fluorine
0% over limit
Discharged 0 mg/L against a permitted limit of 0 mg/L (DAILY MX)
DMR, Monitor Only - Overdue
Copper, total recoverable
7% over limit
Discharged 0.11004 mg/L against a permitted limit of 0.10296 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
Mercury, total recoverable
17% over limit
Discharged 0.00084 mg/L against a permitted limit of 0.00072 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
Cadmium, total recoverable
286% over limit
Discharged 0.01296 mg/L against a permitted limit of 0.00336 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
TU Static Renewal 7-Day Chronic Ceriodaphnia dubia
25% over limit
Discharged 2 toxic against a permitted limit of 1.6 toxic (DAILY MX)
DMR, Limited - Numeric Violation
September 30, 2025
Mercury, total recoverable
250% over limit
Discharged 0.00252 mg/L against a permitted limit of 0.00072 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
Lead, total recoverable
67% over limit
Discharged 0.02004 mg/L against a permitted limit of 0.012 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
Chromium, total recoverable
310% over limit
Discharged 0.05604 mg/L against a permitted limit of 0.01368 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
Cyanide, total [as CN]
39% over limit
Discharged 0.057 mg/L against a permitted limit of 0.04092 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
Zinc, total recoverable
121% over limit
Discharged 0.48035999 mg/L against a permitted limit of 0.21768 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
Copper, total recoverable
464% over limit
Discharged 0.58043999 mg/L against a permitted limit of 0.10296 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
Nickel, total recoverable
33% over limit
Discharged 0.15012 mg/L against a permitted limit of 0.11256 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
June 30, 2025
Chromium, total recoverable
1729% over limit
Discharged 0.25019999 mg/L against a permitted limit of 0.01368 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
Copper, total recoverable
192% over limit
Discharged 0.30023999 mg/L against a permitted limit of 0.10296 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
Zinc, total recoverable
176% over limit
Discharged 0.60047999 mg/L against a permitted limit of 0.21768 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
Nickel, total recoverable
158% over limit
Discharged 0.29027999 mg/L against a permitted limit of 0.11256 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
Cyanide, total [as CN]
66% over limit
Discharged 0.06804 mg/L against a permitted limit of 0.04092 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
March 31, 2025
Chromium, total recoverable
207% over limit
Discharged 0.042 mg/L against a permitted limit of 0.01368 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
Nickel, total recoverable
51% over limit
Discharged 0.17016 mg/L against a permitted limit of 0.11256 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
Zinc, total recoverable
291% over limit
Discharged 0.85067998 mg/L against a permitted limit of 0.21768 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
December 31, 2024
Cyanide, total [as CN]
1526% over limit
Discharged 0.66551999 mg/L against a permitted limit of 0.04092 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
Chromium, total recoverable
303% over limit
Discharged 0.05508 mg/L against a permitted limit of 0.01368 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
Zinc, total recoverable
820% over limit
Discharged 2.00159996 mg/L against a permitted limit of 0.21768 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
Nickel, total recoverable
131% over limit
Discharged 0.26015999 mg/L against a permitted limit of 0.11256 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
November 30, 2024
Mercury, total recoverable
58% over limit
Discharged 0.00101 kg/d against a permitted limit of 0.00064 kg/d (MO AVG)
DMR, Limited - Numeric Violation
Mercury, total recoverable
200% over limit
Discharged 0.00003 mg/L against a permitted limit of 0.00001 mg/L (MO AVG)
DMR, Limited - Numeric Violation
Copper, total recoverable
120% over limit
Discharged 0.033 mg/L against a permitted limit of 0.015 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
Mercury, total recoverable
1677% over limit
Discharged 0.0231 kg/d against a permitted limit of 0.0013 kg/d (DAILY MX)
DMR, Limited - Numeric Violation
Mercury, total recoverable
2400% over limit
Discharged 0.0005 mg/L against a permitted limit of 0.00002 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
Copper, total recoverable
45% over limit
Discharged 1.43200007 kg/d against a permitted limit of 0.99000005 kg/d (DAILY MX)
DMR, Limited - Numeric Violation
September 30, 2024
TU Static Renewal 7-Day Chronic Ceriodaphnia dubia
25% over limit
Discharged 2 toxic against a permitted limit of 1.6 toxic (DAILY MX)
DMR, Limited - Numeric Violation
Mercury, total recoverable
183% over limit
Discharged 0.00204 mg/L against a permitted limit of 0.00072 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
Zinc, total recoverable
75% over limit
Discharged 0.38027999 mg/L against a permitted limit of 0.21768 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
Chromium, total recoverable
68% over limit
Discharged 0.02304 mg/L against a permitted limit of 0.01368 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
Lead, total recoverable
67% over limit
Discharged 0.02004 mg/L against a permitted limit of 0.012 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
TU Static Renewal 7-Day Chronic Ceriodaphnia dubia
50% over limit
Discharged 1.5 toxic against a permitted limit of 1 toxic (MO AVG)
DMR, Limited - Numeric Violation
First flagged
April 14, 2026 (3 months ago)
Last confirmed
July 13, 2026 (23 days ago)