Soil and groundwater pollution in the Como neighborhood of southeast Minneapolis appears to be more widespread than initially thought.

Minnesota Pollution Control Agency officials have notified more than two dozen industrial and commercial properties that they need to be tested for trichloroethylene (TCE) as the agency searches for additional sources of the contaminant. Testing of nearby residential properties over the last few years suggested the pollution could be coming from multiple places.

TCE is an industrial solvent that can get into groundwater, vaporize and enter buildings above it. Long-term exposure has been linked to increased risks of health disorders including cancer and birth defects.

Chemicals including TCE were dumped at a General Mills facility at 2010 E. Hennepin Av. until 1962. In 2013, state officials notified residents living nearby that TCE vapor could be entering their homes, and hundreds underwent voluntary testing and mitigation.

That testing provided a picture of where contamination was coming from, said Hans Neve, a project supervisor at the MPCA. It appears that multiple properties, not just the former General Mills site, are contributing to TCE pollution in the area, he said.

In a statement, General Mills concurred.

“We have acted responsibly addressing an issue that happened in the 1940s and ’50s,” the statement said. “Since that time, abundant evidence from environmental sampling and the Minnesota Pollution Control Agency’s own data demonstrates that disposals by entities other than General Mills in the neighboring industrial area have caused contamination that remains today.”

The focus now is on investigating 26 properties in the area newly designated as the Southeast Hennepin Superfund site. Businesses there range from a craft brewery to an 84-year-old manufacturing company.

Unlike the homes that were tested, the Southeast Hennepin properties may be the source of the pollution that threatens them. But until more testing is done, it’s too soon to point to current or former property owners, Neve said.

“There’s not a place to put an arrow and say ‘Here, this is it, it was dumped or it spilled right here,’ ” he said. “It’s hard to tell until we know more of the story.”

Ongoing lawsuit

Como residents living near the half-mile plume of contamination from the General Mills site are still feeling the aftershocks.

Karl Ebert and his family have lived in the neighborhood for nearly 24 years, and are among the plaintiffs in a federal lawsuit that residents filed against General Mills in late 2013.

“It’s an emotional drain all the time,” Ebert said of the lawsuit, which argues that General Mills must clean up the contamination because it threatens human health and the environment.

“Vapor mitigation systems were never intended to be a permanent protection against groundwater contamination,” said Shawn Collins, an attorney for the residents. “The only permanent protection is to get the chemicals out of the groundwater.”

Regardless of the lawsuit’s outcome, General Mills is still on the hook for monitoring contamination and working with homeowners affected by the decades-old waste. Owners of any Southeast Hennepin properties deemed responsible for the pollution there may have to do the same.

Last month, the MPCA directed General Mills to submit a plan by Jan. 27 for managing current and future mitigation systems, reimbursing property owners for costs associated with operating the systems and continuing to monitor the contaminated area to make sure it doesn’t expand.