Chemical Sector Requirements - MPCA General Permit

The Minnesota Pollution Control Agency (MPCA) has issued its revised multi-sector industrial stormwater discharge general permit (MSGP). This permit will replace the existing industrial stormwater permit, which expired in October of 2002.

[Read a summary of the overall Minnesota permit, stormwater monitoring, and sector requirements]

All manufacturing, industrial and “industrial-like” sites that require a permit to discharge stormwater will be required to come into compliance with the revised permit, and to submit an application for permit coverage by either June 1, August 1 or October 1, depending on their industrial sector.

Click here to review a list affected industrial sectors and application deadlines for each sector

The revised permit details requirements for 29 different industrial sectors. The requirements described below are for the Chemical and Allied Products Manufacturing Sector (Sector C). Sector C covers a fairly broad range of product types, including industrial inorganic and organic chemicals, plastic materials and synthetic resins, synthetic rubbers and human-made fibers, soap and detergents, specialty cleaning, polishing, and sanitation preparations, surface active preparations, perfumes, cosmetics, paints, wood fillers and sealers, paint and varnish removers, adhesives, glues, caulking compounds, explosives, inks, fertilizers, pesticides, and other agricultural chemicals, medicinal and pharmaceutical chemicals. These requirements are in addition to permit requirements that apply to all sectors.

Review requirements that apply to all sectors

Inspections:
The facility must conduct two of the monthly inspections during runoff events. One of the inspections shall be performed during a snow melt runoff event. Each inspection must include a visual assessment of the runoff to identify any visible sheens or films that indicate the presence of oil or grease in the discharge.

Potential Pollutant Sources:
The SWPPP must document describe the following potential pollutant sources: outdoor storage of salt, pallets, coal, drums, containers; access roads, rail cars, and tracks, areas where the transfer of substances in bulk occurs, and areas where machinery operates.

Stormwater Monitoring Benchmarks:
All facilities are required to conduct visual and chemical (benchmark) monitoring. For benchmark monitoring, the benchmark concentrations or values depend on product type:

Agricultural Chemicals (SIC 2873-2879):
COD 120 mg/L
TSS 100 mg/L
Total Zinc 0.234 mg/L
Total Lead 0.164 mg/L
Total Iron 1.0 mg/L
Phosphorus 1.0 mg/L

Industrial Inorganic Chemicals (SIC 2812-2819):
TSS 100 mg/L
Total Aluminum 1.5 mg/L
Total Iron 1.0 mg/L
Total Zinc 0.234 mg/L

Soaps, Detergents, Cosmetics, and Perfumes (SIC 2841-2844):
TSS 100 mg/L
Total Zinc 0.234 mg/L

Plastics, Synthetics, and Resins (SIC 2821- 2824):
TSS 100 mg/L
BOD 25 mg/L
Total Zinc 0.234 mg/L

All Others:
TSS 100 mg/L

Note: Benchmarks for zinc, copper, aluminum, iron, arsenic were derived based on the Aquatic Life Standards for these parameters in Minnesota Rules.

[Read more about use of Aquatic Life Standards to derive stormwater benchmarks]
[Read more about how benchmarks are used under the MPCA industrial permit]
[Read more about what a 100 mg/L benchmark for TSS relates to]


Looking for other sector information?
Click here for a link to all sector requirements

Caltha LLP provides expert consulting services to public and private sector clients nationwide to address Stormwater Permitting & Regulatory Support, Stormwater Pollution Prevention Plans (SWPPP), Stormwater Monitoring and Stormwater Training.

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