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Information regarding TCE Vapor Testing

posted Nov 7, 2013, 1:20 PM by Ricardo McCurley   [ updated Nov 11, 2013, 12:00 PM by Stephanie Hankerson ]
Two public meetings Nov. 12th

Two community meetings are scheduled for residents in the study area Tuesday, Nov. 12, at Van Cleve Recreation Center, 901 15th Ave. SE. The first meeting is 12:30-3 p.m., and the second is 5-7:30 p.m.

During the first hour, there will be an opportunity to talk one-on-one with representatives of the Minnesota Department of Health and the Minnesota Pollution Control Agency (MPCA). Formal presentations, with time for questions and answers, will take place at 1:30 p.m. and 6 p.m.

Additionally, representatives from the MPCA and possibly General Mills will also be present at the SECIA annual meeting on Wed Nov. 13th at 6:30pm (see announcement below). If you want to talk with these representatives, come to the first half hour to visit informational tables.

This is a letter, sent out to residents.  Below is a PDF with further details on TCE and the testing area

November 6, 2013

Dear Resident/Property Owner:

The Minnesota Pollution Control Agency (MPCA), along with state and local partners, will need your help and cooperation for an environmental investigation in your neighborhood over the next several weeks. MPCA will be overseeing an investigation by General Mills, Inc. (GMI). GMI and its contractors will be looking for underground vapors that may be entering homes and buildings. Some of the groundwater in the area is contaminated and could release vapors that can rise through the soil and seep through basement and foundation cracks into indoor air. This is known as “vapor intrusion.” MPCA is requesting that property owners cooperate and allow soil vapor sampling in and around your home or building.

The source of the potential vapor intrusion in the several-block area is related to historic waste disposal activities at 2010 East Hennepin Avenue in Minneapolis, a site owned and operated by GMI from about 1930 until 1977. Beginning in the 1940s, until the early 1960s, solvents were disposed in a soil absorption pit located in the southeast portion of the property. Subsequent discovery of trichloroethylene (TCE), a commonly-used cleaning solvent and degreaser, in the groundwater led to extensive cleanup activities in the area. There is no risk to drinking water supplies.

Representatives from MPCA, Minnesota Department of Health (MDH) and GMI will hold two public meetings this coming Tuesday to update the community on the situation, with additional meetings being planned in the community. At these meetings, property owners and residents will be informed of the testing locations and procedure, as well as the potential health risks of TCE. Testing will be performed using the method approved by the MPCA.

GMI has agreed to install sub-surface vapor ventilation systems, which work like radon mitigation systems, in any home found to have TCE above acceptable levels set by the MPCA in soil-gas beneath the home. uch systems are a proven solution to vapor intrusion problems.

Assistance from the public is needed. Residents and property owners that fall within the dotted area on the enclosed map are being asked to sign an access agreement, which allows your home to be sampled. To ensure quick response times, officials with the MPCA and MDH encourage all residents and property owners to cooperate by allowing access. Sampling could begin as early as the week of November 18. The access agreement can be found online at www.pca.state.mn.us/wdwffra and will be available at the open houses to review and sign. There is no cost to residents or property owners for the testing, and vapor intrusion mitigation systems will be offered and installed at no cost in eligible affected buildings.

Below are some commonly asked questions:

Why am I being asked to participate?

Your property is in one of two areas that MPCA and MDH have identified as the potential investigation area to test for elevated levels of TCE. Tests also found TCE vapor in public rights of way, south and west of the Hennepin Avenue site.

Why are we concerned about TCE vapors in indoor air?

· MDH staff has reviewed the soil gas data collected at this site and are concerned that vapor intrusion may be occurring. Once inside the building, vapors can be inhaled by residents. If vapor intrusion is occurring, it is likely that vapor levels are higher in basements than on upper floors.

· The groups considered to be more sensitive to potential health effects from breathing in TCE vapor include unborn children, infants and children, and/or people with impaired immune systems. Because of the risk of heart defects occurring in developing fetuses, MDH is concerned about TCE exposures in women who are pregnant or who may become pregnant.

How will the sampling be done?

With the owner’s permission, licensed contractors will conduct sub-slab sampling at the target properties to see whether contaminated soil vapors are potentially underneath your home or building. The first step in sampling each residence will be to collect a sub-slab vapor sample. Sub-slab sampling is the name given to the process of collecting a vapor sample from directly underneath the basement floor through a small hole drilled in the floor, which takes about 45 minutes. Sub-slab samples can be more accurate than indoor air samples, which can be cross-contaminated by common household products, such as cleaners and adhesives.

If TCE is detected at my property, how will it be cleaned up?

If the sample results indicate elevated TCE vapor levels above MPCA screening levels, GMI will install a sub-slab ventilation system in the overlying structure. This system is the same as a typical “radon system” commonly installed in homes and buildings in areas where radon is naturally present in the soil. Such systems consist of a hole in the building floor with a sealed pipe that leads to a low-wattage fan in the attic or on the outside of the building. The fan pulls vapors from beneath the floor and discharges them to the atmosphere through a stack on the roof.

Additional information about this project is found at www.pca.state.mn.us/wdwffra. For more information, questions or comments, you can contact these representatives:

Minnesota Pollution Control Agency (for project or testing questions)
Fred Campbell – Site Remediation, (651) 757-2260, fred.campbell@state.mn.us 
Hans Neve– Site Remediation, (651) 757-2608, hans.neve@state.mn.us 

Minnesota Department of Health (for health-related questions)
Rita Messing (651) 201-4916 or Emily Hansen (651) 201-4602 
Site Assessment and Consultation Unit - (651) 201-4897 or (800) 657-3908 

Email health.hazard@state.mn.us or visit us at www.health.state.mn.us/divs/eh/hazardous/topics/tce.html

To schedule sampling, call: Sara Gaffin, Barr Engineering, (952) 832-2935

To contact General Mills, call: (763) 293-1165

Ricardo McCurley,
Nov 7, 2013, 1:20 PM