St. Paul | Morning Star Church area soil contamination

Elevated levels of tetrachloroethylene (PCE) and trichloroethylene (TCE) have been found in soil vapor around this site in St. Paul. These chemicals likely came from businesses previously operating on the site, including a dry cleaner (which commonly used PCE) and a manufacturer. Groundwater contaminated with PCE or other chemicals can release vapors that can rise through the soil and seep through basement and foundation cracks into homes and other buildings, where it could be inhaled by people. This process is known as vapor intrusion.

A potential buyer wants to demolish the Morning Star Church and build a high-rise senior living facility attached to a new church building. During redevelopment, the buyer is planning to excavate soil across the bulk of the site to depths of 10-12 feet to install underground parking.

Plans call for installing a vapor intrusion mitigation system beneath new buildings on the site, and this system will protect occupants from breathing in any vapors. Residents in nearby homes and apartments may not be protected from vapor intrusion caused by the soil contamination.

Health and environmental concerns

Vapor intrusion, or the fouling of indoor air, is the primary health concern at the site, though the amount such vapors in indoor air is usually not high enough to affect most people’s health. The possible health effects from breathing PCE depends on the amount in indoor air and how long people breathe it.

Long-term exposures to PCE at very high levels (thousands of times higher than vapor intrusion levels) may increase the risk of certain types of cancer or cause neurological effects such as vision changes or delayed reaction time.

For more information regarding health and vapor intrusion please go to the Minnesota Department of Health website.


This one-acre parcel on Selby Ave. in St. Paul is in an area of mixed residential and commercial development, and past occupants of the parcel have included residential, commercial, and industrial tenants.

Our role

MPCA staff are currently obtaining access agreements to conduct soil vapor sampling underneath homes in the surrounding area. Soil vapor and groundwater samples from borings may also be used to help define the extent of the area of concern.


Pam Foster
Minnesota Department of Health