St. Louis Park: Minnetonka Blvd. and Raleigh Ave. site

This site is located in an area that is a mixture homes, apartments, government offices and commercial businesses.

Between 1981 and 1998, one building near this intersection was the location of several dry cleaning businesses. In 2001, that building was demolished and redeveloped as Fern Hill Place. The development included a level of underground parking, commercial space on the ground level, and three levels of condominiums.

Map of Minnetonka Boulevard and Raleigh Avenue Area of Concern

What's the problem?

The Minnesota Pollution Control Agency (MPCA) conducted groundwater and soil vapor sampling at Fern Hill Place and several adjacent properties in June 2013. The investigation found elevated levels of tetrachloroethene (PCE) and trichloroethene (TCE). PCE is a chemical that was commonly used by dry cleaning businesses. TCE is a commonly used industrial solvent.

Concentrations of PCE and TCE were more than 10 times the value that the MPCA and the Minnesota Department of Health (MDH) considers safe for groundwater and soil vapor near residential properties.

Groundwater contaminated with PCE can release vapors that can migrate through the soil into nearby homes and buildings where it can pose health risks to the people living and working in them. This is commonly referred to as vapor intrusion. The MPCA wants to take steps to reduce or eliminate it where possible.

Health concerns

When chemical vapors enter buildings through the foundation, the amount in indoor air is usually not high enough to affect most people’s health. The possible health effects from breathing TCE/PCE depends on the amount in indoor air and how long people breathe it.
The Minnesota Department of Health is most concerned about women in the first trimester of pregnancy because TCE exposures may increase the risk of heart defects to the baby.

Exposure to TCE for a long period of time may also affect the immune system. Long-term exposures to TCE/PCE may also increase the risk of certain types of cancer based on studies in workers or animals breathing very high levels of these contaminants (thousands of times greater than what may be found at this site).

For more information regarding health and vapor intrusion please go to the MDH website.

What's being done?

When redevelopment took place at Fern Hill Place, a vapor mitigation was installed. This has been a standard practice since to 2002 to control radon issues. This system needs to be tested to make sure it is working properly.

The MPCA had difficulty gaining access to buildings in the area to conduct needed additional testing. But in November 2017, the agency tested soil vapors beneath the foundations of three of the Uptown West apartment buildings in the area. Results showed that PCE and TCE vapors were present in the soil underneath the buildings at levels that require mitigation systems to be installed to lower the vapor levels.

The MPCA and MDH will be contacting residents in the affected apartment buildings as well as city employees at nearby government offices to alert them to this situation and what will be done to correct it.


Greg Small

Minnesota Department of Health