The former Waldorf Cleaners dry cleaning business operated at 942 Lowry Ave NE, Minneapolis, from the 1940s to the 1980s. The business operated at this address as well as at the adjoining property across the alley to the west. The property to the west was a mechanical building that housed a steam boiler and was used to store chemicals, too.
The Minneapolis Community Development Agency began investigating the site in the early 2000s. Analysis of soil and groundwater samples found tetrachloroethylene (PCE) contamination. PCE, sometimes referred to as "perc," is a commonly used dry cleaning fluid.
What's the problem
In 2017, the site was investigated again by Hennepin County. Soil and groundwater samples once again showed PCE contamination, this time at levels prompting quick action.
When PCE gets into groundwater, it can move off the property or area where the contamination occurred. It can also release PCE vapors back into the soil which can migrate upward 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 identify vapor intrusion and take steps to reduce or eliminate it where possible.
Usually when chemical vapors enter buildings through the foundation, the amount in indoor air is not high enough to affect most people’s health. Exposure to PCE may increase the risk of certain types of cancer based on studies in workers or animals breathing very high levels of PCE — thousands of times greater than what may be found at vapor intrusion sites.
If you have health concerns please contact the Minnesota Department of Health's Site Assessment and Consultation Unit:
- Call — 651-201-4897
- Email — firstname.lastname@example.org
What's being done
In September of 2017, the MPCA mobilized a state contractor to collect samples of the vapors in the soil underneath two homes and one business in the immediate vicinity of old dry cleaning business. These soil gas samples were analyzed to determine what actions, if any, were necessary to ensure the health and safety of residents and workers.
The agency has conducted additional soil gas borings around the site. If the vapor sampling results collected from under the buildings exceed certain levels, a vapor venting system is required to prevent vapors from entering a home. In commercial buildings, there may be other ways to address vapor issues.
Vapor mitigation systems are designed and operate like a home radon mitigation system. The vapor mitigation system creates a slight depressurization beneath the building floor slab using a small fan installed in PVC piping. Vapors collected from beneath the building are then exhausted above the roof line.
Measurements collected before and after installation of the mitigation system are used to verify that the system is functioning properly.
The results of the soil gas samples collected in September 2017, indicate that vapor mitigation systems are needed at all three properties; two homes and one business in the immediate vicinity of old dry cleaning business. The MPCA plans to collect soil vapor samples at three additional properties beyond those sampled in September 2017.
The agency will continue to conduct additional soil gas sampling around the site to help define the extent of contamination.
Minnesota Department of Health
Call — 651-201-4897
Email — email@example.com