Vapor Study Informational Meeting

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 Issue • Health Information • Your Involvement • The Solution

3. Our Missions MDH • To protect, maintain and improve the health ofall Minnesotans MPCA • To protect and improve the environment and enhance human health.

4. Outside: MPCA or EPAInside: MDH MPCA vs. MDH Roles

5. General Mills/Henkel Corp. Superfund Site Disposal “Absorption 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) Groundwater Contamination • 1981contamination confirmed • Groundwater ‘plume’ about ½ mile off the property to the SW • 1985 groundwater pump and treat system installed • 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 frequently found at waste sites • Commonly found in consumer products • 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 • 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 • 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 TCE health based value is 2 mg/m3 in air

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

13. Sub-Slab Vapor Sampling • Goal is to find out is there vapor intrusion • Sample soil vapor directly below basement floor • Results generated quickly • Used for decision-making • Indoor air has contaminants from sources inside the house

14. 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 10 times the health based value • Safe indoor air TCE less than 2 ug/m3 • Sub-slab sample TCE less than 20 ug/m3 No risk from vapor intrusion • Mitigation systems are effective and easy to install

15. What’s next? • Sign an access agreement • Sampling begins the week of November 18 • Mitigation if needed • Mitigation also prevents infiltration of naturally occurring radon gas

16. 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 Minnesota Pollution Control Agency • Hans Neve hans.neve@state.mn.us, (651) 757-2608 • Fred Campbell fred.campbell@state.mn.us, (651) 757-2260

17. Thank You

18. Indoor Air Sampling • 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

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