The MPCA has posted a draft wastewater permit for the 3M Chemical Operations manufacturing facility in Cottage Grove. This updated permit will add new water quality protections for the Mississippi River and improves accountability through monitoring and reporting requirements. The draft permit is one of the most rigorous in state history and mandates the removal of certain per- and polyfluoroalkyl substances (PFAS) to levels below detection. An advanced PFAS wastewater treatment system will treat all types of PFAS and many other pollutants from wastewater, stormwater, and groundwater sources.
This facility produces a wide range of products including abrasives, chemicals, polymers, resins, and tapes. The facility also manufactures various PFAS. It treats its own wastewater, stormwater, and cooling water as well as contaminated groundwater and leachate from a nearby landfill. Additionally, the facility handles water from a local power station and from decommissioning activities related to its incinerator.
The public is invited to review and comment on this draft permit during an extended 60-day public comment period, which includes virtual and in-person meetings.
Our role
The MPCA is committed to safeguarding Minnesota’s natural resources and public health. In this project, our role involves:
- Drafting and enforcing rigorous wastewater permits.
- Monitoring compliance with state and federal environmental regulations.
- Engaging with the public and incorporating their feedback into the final permit.
- Using the latest science and technology to manage PFAS contamination.
Project information
This is a permit reissuance for the facility, which discharges treated wastewater to an unnamed creek that flows into the Mississippi River. Under the draft water quality permit, the facility would be allowed to discharge up to 15.2 million gallons of treated wastewater per day. The draft permit protects water quality for aquatic life, recreation, and human fish consumption by limiting pollutant discharge as required by federal regulations and applicable water quality standards. The draft wastewater permit for 3M’s Cottage Grove facility includes several key provisions:
- Pollution limits: The permit sets stringent limits on the levels of pollutants, including PFAS, in the facility's wastewater. Some PFAS limits are so low they are undetectable. The MPCA must set limits based on federal law, state rules, and water quality standards or criteria.
- Advanced treatment technology: 3M is required to use a new, advanced PFAS wastewater treatment system that did not exist at this scale until recently. This system will treat all types of PFAS, not just those types with limits established in the permit.
- Comprehensive monitoring: The permit calls for increased monitoring of groundwater, the Mississippi River, and aquatic life to ensure compliance and public transparency.
- Accountability: The permit requires 3M to file public reports and to hold an annual community meeting. The MPCA will publish water quality monitoring data from the facility online monthly.
- Public involvement: Public comments will shape the final permit.
Review comments on the permit
The public comment period has closed. Review comments received.
Key dates
- July 29, 2024: First virtual public information session (recorded)
- July 31, 2024: In-person community meeting in Cottage Grove.
- August 20, 2024: Second virtual public information session.
- August 30, 2024: Deadline for public comments on the draft permit, the permit fact sheet, and site-specific water quality criteria.
- Beginning September 2024: Review of public comments and finalization of the permit.
- March 31, 2025: Under the draft permit, 3M Cottage Grove’s advanced wastewater treatment system must be in operation.
- December 31, 2026: Under the draft permit, 3M must be in compliance with new limits. Interim limits are in effect until this date.
Site history
- 1951: 3M begins commercial production of PFOA in Cottage Grove. More types of PFAS would follow.
- 2002: 3M reports PFAS detections in groundwater at 3M Cottage Grove.
- 2003: MPCA issues a wastewater permit.
- 2004: PFAS is found in drinking water in parts of Washington County.
- 2005: MPCA’s “PFCs at the 3M Cottage Grove site” investigation begins.
- 2007: A consent order, still in place today, commits 3M to PFAS remediation measures and drinking water protection for impacted communities.
- 2010: The State of Minnesota sues 3M for natural resource damages from PFAS pollution in the East Metro.
- 2011: MPCA work on a new wastewater permit is paused due to the lawsuit.
- 2018: 3M settles the natural resource damages lawsuit for $850 million.
- 2020: As a result of information received, the MPCA opens a new investigation at 3M Cottage Grove. This investigation is ongoing.
- 2021: 3M Cottage Grove is fined $80,000 and required to take protective measures due to mishandling of hazardous waste.
- 2022: 3M Cottage Grove is fined $2.8 million and required to take corrective measures due to mishandling of hazardous waste.
- Feb. 2024: 3M pays a $4,165 penalty and agrees to corrective action for mishandling hazardous waste.
- May 2024: MPCA issues site-specific water quality criteria for miles 812 to 820 of the Mississippi River.
