1. Vapor Study Informational Meeting General Mills/Henkel Corp. Superfund Site Van Cleve Recreation Center November 12, 2013 Minnesota Department of Health Minnesota Pollution Control Agency

2. What we will cover  The Contamination  Health Information  Your Involvement  The Solution

3. Our Missions MDH  To protect, maintain and improve the health of all Minnesotans MPCA  To protect and improve the environment and enhance human health.

4. MPCA vs. MDH Roles Outside: MPCA or EPA Inside: MDH

5. General Mills/Henkel Corp. Superfund Site Disposal “Adsorption Pit”  Former General Mills research facility 1930-1977  Used and disposed of chemicals on the site from 1947-1962  Main contaminant of concern: Trichloroethylene (TCE) Ground Water Contamination  1981 contamination confirmed  Groundwater ‘plume’ about ½ mile off the property to the SW  1985 groundwater extraction and treatment began  2010 groundwater system turned off, increased monitoring Is There Vapor Intrusion?

8. What are Volatile Organic Compounds (VOCs)?  Chemical solvents used for cleaning and degreasing  Common in consumer products and frequently found at waste sites  Easily evaporate from products, or soil and water if spilled or disposed  The major VOC of concern at the General Mills site is trichloroethylene (TCE)

9. Why is Vapor Intrusion a Possible Public Health Concern?  Studies show people spend about 85 - 90% of their time indoors (even children)  There has been a growing interest in indoor air quality  The science of indoor air assessment has grown tremendously in recent years  Radon gas awareness: Effective January 1, 2014, the Minnesota Radon Awareness Act requires additional disclosure and education be provided to potential home buyers during residential real estate transactions in Minnesota. Before signing a purchase agreement to sell or transfer residential real property, the seller shall disclose in writing to the buyer any knowledge the seller has of radon concentrations in the dwelling.

10. Inhalation Exposure Uncertainties  Difficult to estimate how much is absorbed  Behavior driven  Large differences between individuals  Thus, exposures vary between people MDH health based criteria protect vulnerable people

11. Inhalation health based value for Trichloroethylene: 2  g/m 3 in air  U.S. EPA and MDH recently completed a TCE toxicological review  An increased risk of heart defects in newborns and immune effects were found in recent studies  We now calculate short term values based on exposures that occur in utero, infancy, or early childhood, to ensure values protect everyone’s health

12. U.S. EPA TCE Review Non-cancer effects are driving the risk 12 72 studies 3 critical studies and 2 supporting studies 20 studies Immunosuppression, autoimmune disease, hypersensitivity; decrease in thymus weight; heart defects in the developing fetus Neurologic, kidney, liver, immune, reproductive, and developmental effects kidney effects

13. Groundwater → Soil Vapor → Sub-slab Vapor → Indoor Air Exposure Pathway

14. Sub-Slab Vapor Sampling  Is there “vapor intrusion”?  Sample of the soil vapor directly below basement floor  Indoor air has contaminants from sources inside the house  Results generated quickly  Used for decision-making

15. What if TCE Vapor is Found?  Screening values are very protective – even if exceeded the risk is still very low.  Basement floor and walls provide protection  Level of protection is 10X  Safe indoor air TCE less than 2ug/m 3  Sub-slab sample TCE less than 20ug/m 3 No risk from vapor intrusion

16. What’s next?  Sign an access agreement  Sampling begins the week of November 18  Mitigation if needed

17. Questions Minnesota Department of Health  Rita Messing, Ph.D.: rita.messing@state.mn.us  Emily Hansen, M.S.: emily.hansen@state.mn.us  Site Assessment and Consultation Unit: (651) 201-4897  www.health.state.mn.us/divs/eh/hazardous/index.html Minnesota Pollution Control Agency  Hans Neve hans.neve@state.mn.us, (651) 757-2608  Fred Campbell fred.campbell@state.mn.us, (651) 757-2260  www.pca.state.mn.us

18. Thank You

21. Indoor Air Sampling (not needed)  Typically use stainless steel (Summa) canisters that are under a vacuum  Long-term (up to 24 hour) sample time  Do’s and don’ts: no smoking, don’t use fireplace or candles, do keep windows closed  Home chemicals need to be removed prior to testing to minimize interferences: e.g. TCE in cleaners  Need very low detection limits