MPCA investigating Line 3 drilling fluid spill into Willow River

Sections of the Enbridge Line 3 pipeline are seen crossing the Wetlands on the construction site in Park Rapids, Minnesota on June 6, 2021.  (KEREM YUCEL/AFP via Getty Images / Getty Images)

The Minnesota Pollution Control Agency says it’s investigating a spill of drilling fluid into the Willow River in Aitkin County last week during construction on the Enbridge Energy Line 3 oil pipeline.

About 80 to 100 gallons of drilling fluid, or mud, were inadvertently released on July 6 at a construction site near the town of Palisade, the agency said.

Enbridge is drilling beneath the Willow River to install a new crude oil pipeline to replace the existing Line 3. It’s one of several river crossings along the 340-mile pipeline corridor across northern Minnesota.

Enbridge spokesperson Juli Kellner said the company immediately shut down the drilling operation and crews began containment and cleanup, Minnesota Public Radio News reported.

"There were no impacts to any aquifers nor were there downstream impacts because environmental control measures were installed at this location," Kellner stated.

Environmental groups opposed to the Line 3 project criticized the release, which they call a "frac-out." They say the fine particles in drilling mud could impact aquatic life.

Line 3 would carry Canadian tar sands oil and regular crude from Alberta and across North Dakota and Minnesota to Wisconsin. The project is nearly done except for the Minnesota leg, which is more than halfway complete.