MN Power Now Estimates 5.5M Gallons of Ash Wastewater Leaked at Boswell Energy Center

COHASSET, Minn. — Minnesota Power now estimates 5.5 million gallons of ash wastewater leaked at the Boswell Energy Center. That’s over five times the initial estimate of 1 million gallons discovered on July 16.

The update released on Friday, July 19, confirmed the jump in numbers. The company says, the leak could have an unknown but potentially significant portion of it entrained within the upland soils.

MN Power reported the cause of the spill, which has flowed into Blackwater Lake, as being from a pipeline that transferred wastewater from an inactive coal combustion residual pond to the plant for water processing.

Preliminary monitoring and sampling results indicate increased levels of sulfate and boron in the immediate area where the wastewater entered Blackwater Creek.

Sulfate levels are below the federal drinking water standard, but above Minnesota’s wild rice-based standard.

Initial sampling results from the most impacted area of Blackwater Creek did not detect mercury, arsenic, or selenium.

Minnesota Power says it continues to work with state and federal agencies and the Leech Lake Band of Ojibwe to evaluate and mitigate the ash wastewater spill.

No immediate impacts to fish or aquatic plants have been observed to date.

Mitigation activities also will continue over the weekend.