MATHESON TRI-GAS, INC.

NPDES permit LA0127094 · Minor NON-POTW · effective, expires 2027-12-14 · EPA's file as of 2026-09-19

Check this month's numbers before you file
Watch this permit — $79 a month. Every Monday, from EPA's newest files: the next report due and when, whether EPA's file holds your last one, any change to this permit's limits or status, and the renewal date.

EPA's record, 2025-09-01 to 2026-08-31

10values over a limit
0required values missing, on 0 form(s)
1of 22 forms filed late

Last period with anything received: 2026-06-30. Most often over: Cyanide, total [as CN] (5), Copper, total [as Cu] (3), Mercury, total [as Hg] (1).

Reporting

Reports are due about 28 days after each monitoring period ends (read off this permit's own late-day counts in EPA's filings).

Limits in force (48)

OutfallParameterStatisticLimitMonths
001Temperature, water deg. fahrenheitINST MIN report only all year
001Temperature, water deg. fahrenheitINST MIN report only all year
001Temperature, water deg. fahrenheitINST MAX <= 99 deg F all year
001Temperature, water deg. fahrenheitINST MAX <= 99 deg F all year
001pHINST MIN >= 6 SU all year
001pHINST MIN >= 6 SU all year
001pHINST MAX <= 9 SU all year
001pHINST MAX <= 9 SU all year
001Oil & GreaseMO AVG < 10 mg/L all year
001Oil & GreaseMO AVG < 10 mg/L all year
001Oil & GreaseDAILY MX <= 15 mg/L all year
001Oil & GreaseDAILY MX <= 15 mg/L all year
001Oil & GreaseMO AVG <= 11.36 lb/d all year
001Oil & GreaseMO AVG <= 11.36 lb/d all year
001Oil & GreaseDAILY MX <= 22.72 lb/d all year
001Oil & GreaseDAILY MX <= 22.72 lb/d all year
001Carbon, tot organic [TOC]DAILY MX <= 50 mg/L all year
001Carbon, tot organic [TOC]DAILY MX <= 50 mg/L all year
001Cyanide, total [as CN]MO AVG <= .000239 lb/d all year
001Cyanide, total [as CN]DAILY MX <= .000568 lb/d all year
001Copper, total [as Cu]MO AVG <= .001 lb/d all year
001Copper, total [as Cu]DAILY MX <= .0024 lb/d all year
001Lead, total [as Pb]MO AVG <= .016 lb/d all year
001Lead, total [as Pb]DAILY MX <= .038 lb/d all year
001Phenolics, total recoverableMO AVG <= .053 lb/d all year
001Phenolics, total recoverableDAILY MX <= .126 lb/d all year
001Flow, in conduit or thru treatment plantMO AVG report only all year
001Flow, in conduit or thru treatment plantMO AVG report only all year
001Flow, in conduit or thru treatment plantDAILY MX report only all year
001Flow, in conduit or thru treatment plantDAILY MX report only all year
001Mercury, total [as Hg]MO AVG <= .0000183 lb/d all year
001Mercury, total [as Hg]DAILY MX <= .0000435 lb/d all year
002pHINST MIN >= 6 SU all year
002pHINST MAX <= 9 SU all year
002Oil & GreaseDAILY MX <= 15 mg/L all year
002Carbon, tot organic [TOC]DAILY MX <= 50 mg/L all year
002Zinc, total [as Zn]MO AVG report only all year
002Zinc, total [as Zn]DAILY MX report only all year
002Flow, in conduit or thru treatment plantMO AVG report only all year
002Flow, in conduit or thru treatment plantDAILY MX report only all year
003pHINST MIN >= 6 SU all year
003pHINST MAX <= 9 SU all year
003Oil & GreaseDAILY MX <= 15 mg/L all year
003Carbon, tot organic [TOC]DAILY MX <= 50 mg/L all year
003Zinc, total [as Zn]MO AVG report only all year
003Zinc, total [as Zn]DAILY MX report only all year
003Flow, in conduit or thru treatment plantMO AVG report only all year
003Flow, in conduit or thru treatment plantDAILY MX report only all year

Built from EPA's ECHO bulk files. EPA's file, not the permit document, is the source: read your permit. Check a report before you file it · All states