The U.S. Environmental Protection Agency (EPA) has launched a superfund investigation into underground chemical vapors recently discovered in an area of St. Louis Park.
At a press conference Tuesday, officials stressed there is no evidence of human exposure to the chemicals, which include perchlorethylene and trichloroethylene. But they’re concerned the vapors could seep into basements. They sent a letter to about 270 residents of the southwestern suburb Monday asking to conduct tests in their homes.
“At this point we have no reason to suspect there are vapors present in structures,” said Jim Kelly, a health risk assessor with the Minnesota Department of Public Health.
The area is centered on the intersection of Highway 7 and Wooddale Avenue, about two miles due west of Lake Calhoun in Minneapolis. In addition to the homes, the study’s territory also includes a community center, a high school and a Spanish-immersion school. Chemical testing at the schools began over the weekend.
The chemicals are known as volatile organic compounds, or VOCs, and they’re used for dry-cleaning fabrics and degreasing metal parts. They’re also found in many common household products like paint, carpet and cleaning solutions. When inhaled over long periods of time, even low concentrations can impact health.
Dan Haugen :: EPA Investigating Underground Chemical Vapors in St. Louis Park
The contamination was first detected in a city of Edina drinking water well in 1995. The city shut down the well in October 2003 after contamination exceeded federal standards. A search for the source by city and state investigators eventually led them to more ground water contamination in St. Louis Park.
The St. Louis Park contamination is too shallow to affect its drinking water aquifers, Minnesota Pollution Control Agency Commissioner Brad Moore said Tuesday. Authorities are concerned, however, about the potential for vapors from the chemicals to find their way into basements.
State consultants last winter studied soil gas samples taken eight feet below the surface from 22 locations around the city. All tested positive for the volatile chemical vapors, which led officials to contact the EPA. Another round of outdoor testing this summer better defined the affected area, and now officials want to test for indoor contamination.
“We want to make sure the vapors are not seeping into homes,” Moore said.
Authorities are not recommending that homeowners take any special precautions in light of the vapors. They are asking for cooperation as they continue studying the scope and source. An federal environmental response team out of Cincinnati plans to start testing homes the middle of next month but before that they need permission from property owners.
A pair of meetings is scheduled at the St. Louis Park Recreation Center, 3700 Monterey Dr., to explain the process for residents. The first is at 7 p.m. Dec. 13 and the second at 2 p.m. Dec. 15.
The number of homes included in the study area is on scale with a couple recent major environmental remediations in Minneapolis. More than 200 homeowners’ yards were contaminated with arsenic from the CMC Heartland site in south Minneapolis, and 260 properties in northeast Minneapolis were contaminated by asbestos from the Western Mineral Products/W.R. Grace plant.
Investigators have not yet been able to pinpoint the source of the chemicals, EPA spokesman Mick Hans said. They think there could be more than one source because several machine shops historically operated in a nearby industrial rail corridor and still do so today.
At high concentrations the chemicals would have an odor, but at the levels they’ve been observed they would be undetectable by scent, Kelly said. The vapors aren’t harmful outdoors, where they are rapidly diluted.
The Minnesota Pollution Control Agency, the Minnesota Department of Health and the city of St. Louis Park are assisting the EPA with the investigation.