The inaugural 3M Cottage Grove site community meeting lacked community. To a nearly empty room save one Hastings Journal reporter, 3M Cottage Grove site manager Derek Kneir spoke to the history of the site and a number of current projects from the Advanced Water Treatment System, to the decommissioning of the site’s incinerator.

The Minnesota Pollution Control Agency mandated the meeting be held before the end of the year, and Kneir, along with a number of 3M staff showcased products made on site and explained recent steps made to address the dumping of PFAS and other ecological concerns from that site. The meeting took place Wednesday, Dec. 10 at Cottage Grove City Hall.

Origins
3M was founded in 1902 in Two Harbors, Minn. as Minnesota Mining Manufacturing Company. In the ensuing 123 years, the company has grown to produce some 55,000 products with more than 60,000 employees operating in 48 countries and selling products in more than 200.
“You’re oftentimes within 10 feet of a 3M product,” said Kneir about the proliferation and expanse of 3M products, from producing components within catalytic converters, semiconductors and electric vehicles along with to abrasives in grinding wheels and sandpaper to the famous Post-it note.
The 3M Cottage Grove site sits on about 1,700 acres directly on the banks of the Mississippi River. The site has some 650 employees with an additional 75 contractors.
“We are a small village around the site,” said Kneir.
Its buildings cover 1.5 million square feet, housing manufacturing, process development centers, pilot test areas and several other facilities.

Advance Water Treatment System
The main project highlighted by Kneir at the site was the new advanced water treatment system. The system is meant “for further removal and additional treatment of PFAS” to wastewater at the site before it is disposed, said Kneir.
Construction for the advanced water treatment system began in 2021 and was completed earlier this year with a total cost of $300 million.
The advanced water treatment system uses a series of different treatment methods to treat water before it is disposed of at the site from ultra filtration to reverse osmosis, granular activated carbon filters, ion exchange and brine concentration.
Kneir called the system the “most advanced water treatment in the country.”
The system treats water from a number of sources, including processed water, storm water, ground water and sanitary water from the site.
“We continue to prioritize water treatment at the site even after our PFAS manufacturing exit by the end of the year,” said Kneir.
The advanced water treatment system was constructed only three years after the State of Minnesota and 3M came to an $850 million settlement regarding 3M dumping sites disposing of PFAS-contaminated water across Washington County. Those funds are currently being used to construct water treatment plants across the county, and have been tied to well #5 in Hastings in addition to a number of private wells outside of Washington County. They are expected to run out before 2030.
It is the official stance of the city of Hastings that the PFAS contamination within its drinking water came from nearby 3M dumping sites, and continued ecological studies from the city and MPCA are ongoing, attempting to continue to prove that connection beyond well #5.
Rather than the settlement or new federal standards for PFAS in drinking water, Kneir referenced shareholder expectations in the creation of the system, a sentiment echoed in 3M’s stated reason for ending its manufacture of PFAS by the end of this year.
While 3M, like many companies, still uses PFAS across a number of products, it will stop the manufacture of PFAS as of the end of 2025. 3M began manufacturing PFAS at the site in the 1950s. While the manufacture of PFOS and PFOA, two the most common and most studied types of PFAS ended at the Cottage Grove site after the turn of the century, other types of PFAS continue to be manufactured there.
Last year, Hastings’ city water tested above the new federal limit for PFOA and PFOS. Federal limits changed to 4 parts per trillion (ppt). That amount is roughly the size of a raisin within an Olympic swimming pool.
According to the Hastings 2024 Drinking Water report, city water has 4.37 ppt for PFOS and 21.34 ppt for PFOA, more than five times the new federal limit.
“Our monitoring data is public via the MPCA. We submit monthly, quarterly, annual [reports]. A lot of data in our sample results there to ensure compliance,” said Kneir.
3M staff were unable to answer a number of questions regarding previous dumping practices at the Cottage Grove site and the ecological concerns of those practices, as well as the ramifications of those previous dumping practices for nearby communities. Staff were unable to provide the reason for decommissioning the Cottage Grove site’s incinerator and the ecological impacts of it. They asked that these questions be emailed in order to be able to provide a detailed and accurate response.
3M communication staff did not respond to multiple follow-up emails from the meeting for comment.