MATHESON TRI-GAS, INC.
NPDES ID: LA0127094
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: 2 effluent violations.
Violations
March 31, 2026
Cyanide, total [as CN]
63% over limit
Discharged 0.00017706 kg/d against a permitted limit of 0.00010851 kg/d (MO AVG)
DMR, Limited - Numeric Violation
Cyanide, total [as CN]
2048% over limit
Discharged 0.0055388 kg/d against a permitted limit of 0.00025787 kg/d (DAILY MX)
DMR, Limited - Numeric Violation
Copper, total [as Cu]
43% over limit
Discharged 0.00155722 kg/d against a permitted limit of 0.0010896 kg/d (DAILY MX)
DMR, Limited - Numeric Violation
December 31, 2025
Phenolics, total recoverable
77% over limit
Discharged 0.101242 kg/d against a permitted limit of 0.057204 kg/d (DAILY MX)
DMR, Limited - Numeric Violation
Cyanide, total [as CN]
2048% over limit
Discharged 0.0055388 kg/d against a permitted limit of 0.00025787 kg/d (DAILY MX)
DMR, Limited - Numeric Violation
Cyanide, total [as CN]
63% over limit
Discharged 0.00017706 kg/d against a permitted limit of 0.00010851 kg/d (MO AVG)
DMR, Limited - Numeric Violation
September 30, 2025
Mercury, total [as Hg]
180% over limit
Discharged 0.00005539 kg/d against a permitted limit of 0.00001975 kg/d (DAILY MX)
DMR, Limited - Numeric Violation
Copper, total [as Cu]
54% over limit
Discharged 0.0016798 kg/d against a permitted limit of 0.0010896 kg/d (DAILY MX)
DMR, Limited - Numeric Violation
June 30, 2025
Copper, total [as Cu]
43% over limit
Discharged 0.00155722 kg/d against a permitted limit of 0.0010896 kg/d (DAILY MX)
DMR, Limited - Numeric Violation
March 31, 2025
Copper, total [as Cu]
111% over limit
Discharged 0.00229724 kg/d against a permitted limit of 0.0010896 kg/d (DAILY MX)
DMR, Limited - Numeric Violation
December 31, 2024
Copper, total [as Cu]
85% over limit
Discharged 0.00201576 kg/d against a permitted limit of 0.0010896 kg/d (DAILY MX)
DMR, Limited - Numeric Violation
Mercury, total [as Hg]
567% over limit
Discharged 0.00005539 kg/d against a permitted limit of 0.00000831 kg/d (MO AVG)
DMR, Limited - Numeric Violation
September 30, 2024
Mercury, total [as Hg]
180% over limit
Discharged 0.00005539 kg/d against a permitted limit of 0.00001975 kg/d (DAILY MX)
DMR, Limited - Numeric Violation
Copper, total [as Cu]
275% over limit
Discharged 0.00409054 kg/d against a permitted limit of 0.0010896 kg/d (DAILY MX)
DMR, Limited - Numeric Violation
First flagged
April 14, 2026 (3 months ago)
Last confirmed
August 1, 2026 (4 days ago)