Soil in and around some Southeast Como properties may contain unsafe levels of a common chemical solvent that was used by General Mills in the mid-1900s.

Over the next several weeks, General Mills contractors will test the ground in homes near the old site for trichloroethylene, or TCE — provided there is consent from owners.

The Minnesota Department of Health and the Minnesota Pollution Control Agency sent letters to residents Wednesday asking them to allow testing, and teams will go door-to-door to ask for permission.

After tests for TCE around the neighborhood came in higher than normal, officials want to determine if soil vapor — the air between small cracks in the ground — containing TCE has seeped from contaminated soil through cracks in basements.

Officials knew of the TCE on the former General Mills site for decades, said Rita Messing, a state health department toxicologist, but the potential for the chemical to seep through foundations and basements “is a relatively new concept.”

“The problem’s been there, but we didn’t know it was there,” Messing said.

TCE has been linked to health issues, including birth defects and liver and kidney cancer. Messing said those complications come from TCE concentrations 10 to 100 times higher than what’s likely in Southeast Como.

“We want to see whether there is a problem,” she said. “We don’t really know, [and] that’s why we want to test.”

Initial testing for about 200 properties is scheduled to begin Nov. 18.

Owners can sign up for testing online or at one of two informational meetings at the Van Cleve Recreation Center on Tuesday.

Renters cannot sign up for testing. Instead, officials are asking tenants to provide contact information for their landlords.

“It’s ultimately up to the owner whether we even go in the front door,” said Sam Brungardt, a public information officer with the MPCA.

General Mills will pay to install a ventilation system in any property containing unsafe levels of TCE. Messing estimated the cost of one ventilation system to be about $2,000.

A long history of waste, cleanup

General Mills dumped TCE on its Hennepin Avenue property for 15 years as part of its chemical research efforts, according to the MPCA.

Officials learned the land was contaminated in 1981, four years after General Mills sold the property. The company paid to clean the site up, starting in 1985.

The chemical never posed a threat to the neighborhood’s drinking water supply because no wells drew from the area contaminated with TCE, according to the state health department. State officials determined in 2010 that TCE levels were low enough to end cleanup efforts.

Katie Fournier, a longtime neighborhood resident, lives in the area officials have deemed most important for testing.

She said she was encouraged by the fact that officials kept monitoring the neighborhood after cleanup efforts ended.

“They’re doing the right things to check on it and take care of it,” Fournier said.

To maximize testing, she said, community members could reach out to tenants and ask them to pressure their landlords to consent to testing.

“I’m sure the residents of the home have more of a stake in this than perhaps the owner who lives in Florida,” Fournier said.

Hans Neve, a MPCA supervisor for areas like the former General Mills site, said officials won’t be able to solve the problem without cooperation from the public.

“The solution on this, fundamentally, is a coming-together.”