MEMC, LLC
NPDES ID: MO0000299
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: 3 effluent violations.
Violations
April 30, 2026
Chloride
44% over limit
Discharged 304 mg/L against a permitted limit of 211 mg/L (MO AVG)
DMR, Limited - Numeric Violation
Chloride
1% over limit
Discharged 304 mg/L against a permitted limit of 301 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
March 31, 2026
Chloride
30% over limit
Discharged 391 mg/L against a permitted limit of 301 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
Chloride
50% over limit
Discharged 317.5 mg/L against a permitted limit of 211 mg/L (MO AVG)
DMR, Limited - Numeric Violation
February 28, 2026
Chloride
50% over limit
Discharged 317 mg/L against a permitted limit of 211 mg/L (MO AVG)
DMR, Limited - Numeric Violation
Chloride
5% over limit
Discharged 317 mg/L against a permitted limit of 301 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
November 30, 2025
Chloride
3% over limit
Discharged 217 mg/L against a permitted limit of 211 mg/L (MO AVG)
DMR, Limited - Numeric Violation
October 31, 2025
Chloride
11% over limit
Discharged 333 mg/L against a permitted limit of 301 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
Chloride
50% over limit
Discharged 317 mg/L against a permitted limit of 211 mg/L (MO AVG)
DMR, Limited - Numeric Violation
September 30, 2025
Chloride
25% over limit
Discharged 375 mg/L against a permitted limit of 301 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
Chloride
78% over limit
Discharged 375 mg/L against a permitted limit of 211 mg/L (MO AVG)
DMR, Limited - Numeric Violation
April 30, 2025
Chloride
18% over limit
Discharged 248 mg/L against a permitted limit of 211 mg/L (MO AVG)
DMR, Limited - Numeric Violation
March 31, 2025
Chloride
43% over limit
Discharged 429 mg/L against a permitted limit of 301 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
Chromium, hexavalent dissolved [as Cr]
0% over limit
Discharged 0 mg/L against a permitted limit of 0.015 mg/L (DAILY MX)
DMR, Limited - Overdue
Chloride
103% over limit
Discharged 429 mg/L against a permitted limit of 211 mg/L (MO AVG)
DMR, Limited - Numeric Violation
Chromium, hexavalent dissolved [as Cr]
0% over limit
Discharged 0 mg/L against a permitted limit of 0.0074 mg/L (MO AVG)
DMR, Limited - Overdue
February 28, 2025
Chloride
35% over limit
Discharged 285 mg/L against a permitted limit of 211 mg/L (MO AVG)
DMR, Limited - Numeric Violation
January 31, 2025
Chloride
10% over limit
Discharged 232 mg/L against a permitted limit of 211 mg/L (MO AVG)
DMR, Limited - Numeric Violation
December 31, 2024
Toxicity [chronic], Pimephales promelas [Fathead Minnow]
0% over limit
Discharged 0 toxic against a permitted limit of 0 toxic (DAILY MX)
DMR, Monitor Only - Overdue
Toxicity [chronic], Pimephales promelas [Fathead Minnow]
0% over limit
Discharged 1 toxic against a permitted limit of 0 toxic (DAILY MX)
DMR, Monitor Only - Overdue
Toxicity [chronic], Ceriodaphnia dubia
0% over limit
Discharged 0 toxic against a permitted limit of 0 toxic (DAILY MX)
DMR, Monitor Only - Overdue
Toxicity [chronic], Ceriodaphnia dubia
0% over limit
Discharged 1 toxic against a permitted limit of 0 toxic (DAILY MX)
DMR, Monitor Only - Overdue
Toxicity [chronic], Ceriodaphnia dubia
0% over limit
Discharged 0 toxic against a permitted limit of 0 toxic (DAILY MX)
DMR, Monitor Only - Overdue
Toxicity [chronic], Pimephales promelas [Fathead Minnow]
0% over limit
Discharged 0 toxic against a permitted limit of 0 toxic (DAILY MX)
DMR, Monitor Only - Overdue
October 31, 2024
Chloride
14% over limit
Discharged 240 mg/L against a permitted limit of 211 mg/L (MO AVG)
DMR, Limited - Numeric Violation
August 31, 2024
Chloride
36% over limit
Discharged 410 mg/L against a permitted limit of 301 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
Chloride
94% over limit
Discharged 410 mg/L against a permitted limit of 211 mg/L (MO AVG)
DMR, Limited - Numeric Violation
First flagged
April 14, 2026 (3 months ago)
Last confirmed
August 1, 2026 (5 days ago)