Testing found elevated levels of tetrachloroethylene/perchloroethylene (PCE or Perc) and trichloroethylene (TCE) in soil vapors around the intersection of Selby Avenue and Grotto Street N. in Saint Paul. The contamination likely came from former businesses operating on the property, including a dry cleaner that used PCE.
Soil and groundwater contaminated with PCE, its breakdown products, or other chemicals can release vapors. They can rise through the soil and enter buildings through cracks in basements and foundations, where people can inhale them. This process is known as vapor intrusion. Some soil vapor levels near the site exceed limits set by the Minnesota Pollution Control Agency (MPCA) and the Minnesota Department of Health.
The MPCA added the site to the Minnesota Permanent List of Priorities (PLP) in 2026 and continues site evaluation and cleanup work after a public notice and comment period that did not generate comments.
The property was redeveloped in 2018 with construction of a church connected to a senior living facility. Soil was excavated to depths of 10 to 12 feet to accommodate one level of underground parking. A vapor mitigation system was installed to protect people from breathing contaminated air.
The MPCA began evaluating buildings near the Selby and Grotto site after measuring high concentrations of PCE in 2018. Since then, MPCA evaluated 40 buildings. By 2025, vapor mitigation systems were installed in 20 of those buildings to protect human health. The MPCA also notified an additional 11 property owners that their buildings qualify for mitigation systems.
The agency expects to continue installing vapor mitigation systems as needed. In addition, the MPCA will continue sampling and assessing nearby buildings for PCE vapors. The MPCA plans to conduct additional groundwater and soil testing to determine the extent of contamination.
Health and environmental concerns
Vapor intrusion, or the movement of contaminated soil vapors into indoor air, is the primary health concern at the site. The possible adverse health effects from breathing PCE depends on the amount in the air and how long people breathe it. For more information regarding health risks and vapor intrusion, visit the Minnesota Department of Health website.
Long-term PCE exposure is associated with adverse health effects and may cause cancer.
Location
The site is a one-acre parcel around the intersection of Selby Avenue and Grotto Street N. in St. Paul. Residential and commercial buildings occupy the site.
Our role
MPCA staff are testing for soil vapors in buildings in the surrounding area. With the site listed on the Minnesota PLP, MPCA staff will continue to investigate the extent of contamination of groundwater and determine if residential or commercial buildings are at risk for vapor intrusion.