COTTAGE GROVE, MN (WCCO) – Minnesota pollution regulators say one of the state’s largest companies mishandled hazardous waste on multiple occasions over a period of more than two decades.
The Minnesota Pollution Control Agency began investigating 3M’s Cottage Grove facilities in June 2020 and released its findings Thursday.
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The MPCA found multiple violations, including that 3M misidentified hazardous waste sent to its incinerators as non-hazardous for at least nine years between 1996 and 2021.

3M’s Cottage Grove installation (Credit: CBS)
Between 2015 and 2020, the MPCA said, 3M had not had the incinerator’s lab analysis verified by a third-party lab, which is required by its license.
The investigation also revealed that, from 2014 to 2020, 3M failed to verify that 1,800 waste stream profiles did not exceed hazardous material limits.
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Since 2016, 3M has failed to obtain comprehensive hazardous materials data from third parties who send waste to the facility, according to the MPCA.
3M also stored about 1,300 hazardous waste containers in unapproved areas, the MPCA said, and half of those containers were stored longer than the one-year limit. The company has reported six releases of compromised storage containers in as many months, according to the MPCA.
The MPCA said the air at the site is being monitored and “it does not appear that the incineration of hazardous materials related to this investigation has exceeded limits and resulted in a violation of 3M’s air permits.”
The company will pay a $2.8 million fine for the violations and has also implemented 24 corrective actions to bring the facility up to code.
The incinerator at the Cottage Grove facility ceased operations in December.
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WCCO awaits comments from 3M.