Testing shows low levels of 3M incinerator pollutants
Second-year monitoring at the controversial hazardous waste incinerator at 3M-Cottage Grove continues to show low levels of air pollution emissions.
The first-quarter report, recently reviewed by the city’s Environmental Commission and City Council, addresses the permit the plant was granted last year to burn non-3M waste material in its industrial-sized incinerator.
In June, Short Elliott Hendrickson, Inc. (SEH), a St. Paul-based engineering firm, conducted an air monitoring test at the same location as last year and collected seven samples in search of particulates, select heavy metals and volatile organic compounds (VOC).
The tests were sent to Pace Analytical in Minneapolis for analysis, the same firm that handled the first year’s analysis. However, this year Pace subcontracted the metals and particulate matter analyses to a Michigan-based company, where alarming numbers were discovered.
Preliminary records showed “significant levels” of the chemical methyl ethyl ketone being released, City Engineer Jennifer Levitt said.
“I questioned this because we collected air samples on the same day (Pace) did and found no indication or explanation for why (the significant levels) occurred,” she said.
Investigating further, Levitt said the lab discovered an error in the data.
In a memo to the city, Thomas Henning, senior air quality permitting and compliance specialist at SEH, reported that after reviewing the internal quality data, “the laboratory determined the sample had been influenced by another sample analyzed at the lab.”
The reading was later invalidated.
“The data is not accurate and we have confirmed that,” Levitt said.
Other findings show that the majority of VOCs were not detected in ambient samples.
Henning added that the “detection limits for the metals analysis (is) at or below the detection limits obtained by Pace in the first year of monitoring.”
These first-quarter results, Henning said in the memo, are preliminary as they only serve as the first seven of an expected 30 samples that will be taken during this second year of monitoring.