Estimated 400 gallons of oil spilled into Menomonee River in 'transfer error,' from Komatsu

MILWAUKEE (CBS 58) -- Cleanup efforts continue after an estimated 400 gallons of oil spilled into the Menomonee River due to an "oil transfer error" at a Komatsu facility.

According to the Wisconsin Department of Natural Resources, the spill began on Dec. 3 and the agency, as well as the Environmental Protection Agency, was notified by Komatsu on Dec. 4.

The company's on-site storm sewer drains into the Menomonee River.

Komatsu sent a statement to CBS 58 saying in part that they, "are in the midst of investigating how this very regrettable accident occurred and we are focused on continuing to implement aggressive cleanup efforts to remediate the situation as quickly as possible."

"It's really disheartening," Cheryl Nenn with Milwaukee Riverkeeper told CBS 58. "Our organization and many other community partners have worked really hard for decades to clean up the river and so it's always sad to see something like this happen. Clearly it was an accident, but we are concerned about the impacts of this on water quality and aquatic life and birds as well."

Experts believe weather this weekend may hamper cleanup efforts.

MENOMONEE RIVER OIL SPILL: @WDNR says about 400 gallons of oil were spilled into the Menomonee River. DNR confirmed mining company Komatsu experienced an "oil transfer error" on Dec. 3. This drone video by @CBS58 photojournalist Cody Bergquist shows the magnitude of the spill. pic.twitter.com/2dSrmngBsx

— Victor Jacobo (@victorjacobo_) December 10, 2021

"We might get rain and some weather here in a little bit and that increases the likelihood some of this product will wash into [Lake Michigan]," Nenn said.

Dr. Patrick McNamara, an associate professor of environmental engineering at Marquette University said it is not likely for the oil spill to impact the area's drinking water supply, but it remains a concern.

"That would be the real human public health concern, that this contaminates any drinking water source," McNamara said. "But again we do have treatment plants that should hopefully take care of this and it's not like this spill happened right next to an intake."

The public is asked to help report areas where the oil spillage may be seen. They can reach out to Milwaukee Riverkeeper. More information can be found on the organization's website here

Komatsu's full statement can be found here: