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Continued: Minnesota's Vapor Trail: Tracking toxic gases in basements

  • Article by: JEREMY OLSON , Star Tribune
  • Last update: March 31, 2014 - 9:26 AM

Minnesota’s change in cleanup policy is reflected in sites such as the old Despatch Laundry and Whiteway Cleaners at E. 26th Street and Stevens Avenue S. in Minneapolis. There, in 2000, the public was assured that cleaning chemicals dumped in the ground presented no imminent vapor risk.

Early advice was wrong

“Inhalation exposure to PCE vapors that may have migrated through soil and building foundations is unlikely, particularly any distance from the site,” an MPCA advisory letter indicated at the time.

Fast forward a decade, and MPCA data show that vapor tests were conducted at 17 homes — two of which received mitigation systems to prevent vapor risks. Permanganate was injected into the ground because the chemical neutralizes PCE.

State pollution experts have charted an unpopular course in reviewing such sites and disclosing to neighbors that sites once believed safe are presenting the potential for environmental and health hazards.

In Como, many nervous residents have limited their access or their children’s access to basements — even if testing has found low TCE levels. In some cases, the properties are basement apartments for U students.

Stine said state officials will work swiftly in each case to notify residents of vapor risks and address them.

“It’s a huge undertaking,” he said. “There’s some good news in the speed that we’re moving in getting these sites assessed. We’ve got more than half of them evaluated for risk.”

Among active sites, 162 have either been cleared of vapor risks or cleaned up sufficiently to remove those risks.

Among some of the 80 sites still under investigation, cleanup efforts are underway. Forty mitigation systems were installed in homes in St. Louis Park, where investigators still are tracing the source of TCE contamination that was initially discovered in 2007 in an Edina water well.

A looming issue for the MPCA — one that hasn’t been accounted for in its budget — is the cost of reopening investigations into old Superfund sites. The agency is preparing to test a few sites this year to ­determine how severe soil vapor problems might be, Stine said.

Today, Coral Sadowy spends considerably less time in her home. With cancer treatments approaching that will weaken her immune system, she worries about exposure to any contaminants. A negative air pressure system has yet to be installed, because engineers for General Mills have determined that a new basement floor will be needed for the system to work.

A retired Realtor who doubts her house will be sellable for years, Sadowy has another idea: “I wish they’d just tear it down, dig a big hole and suck that stuff out of there.”


Jeremy Olson • 612-673-7744

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