HEALTH CONSULTATION
Vapor Intrusion Investigation
JOHNSON CONTROLS INCORPORATED BADGER FACILITY
(a/k/a JOHNSON CONTROLS-BADGER FACILITY)
MILWAUKEE, MILWAUKEE COUNTY, WISCONSIN
The Wisconsin Department of Health and Family Services (DHFS) was asked by the Wisconsin Department of Natural Resources (WDNR), the Milwaukee Department of Public Health, and the Milwaukee Redevelopment Authority to assess possible vapor intrusion of chlorinated solvents from the former Johnson Controls Inc.-Badger Facility (JCI) into the basements of nearby private residences. Groundwater monitoring and soil sampling conducted on JCI and adjacent property indicates that volatile organic compounds (VOCs) on this site are sufficiently concentrated to present a potential vapor intrusion threat to nearby residences. The remediation of this property is currently being planned. The vapor intrusion pathway is being formally investigated and addressed as part of the scope of work at this site. Vapor migration will be an issue at the JCI site as long as the contaminant sources remain. These sources should be removed to prevent on- and off-site vapor migration concerns.
BACKGROUND AND STATEMENT OF ISSUES
This public health consultation summarizes the DHFS review of site information and documents pertaining to environmental investigation and remediation work at the former Johnson Controls facility in Milwaukee, Wisconsin. DHFS recommendations have been incorporated into ongoing investigation at this property.
The former Johnson Controls facility is located at 3238 N. Bremen, Milwaukee. The property is currently a fenced, grass-covered, 2.8 acre vacant lot surrounded by an older (1930-1940s housing stock) residential neighborhood. The property had been used for storage and manufacturing since 1910, including the manufacture of radio components by Globe Union Inc. from 1944 to the 1970s (Earth Tech, 2003). Environmental investigations beginning in 1992 report the presence of volatile organic compounds, most significantly xylenes, tetrachloroethene, cis-1,2-dichloroethylene, trichloroethene, and petroleum-related compounds in soil and groundwater on the property. Since 1998, all buildings and surface structures have been removed from the property. In 1999, 9,115 tons of soils contaminated with chlorinated solvents were excavated and thermally treated on-site. Presently, consultants representing JCI have proposed an investigative work plan (Earth Tech 2003). Part of the 2003 investigative work plan is directed toward ruling out the potential for vapor intrusion into nearby homes and toward establishing the property as suitable for residential redevelopment. At the request of WDNR, DHFS reviewed the investigative work plan proposed for the former JCI-Badger Facility property.
Site visit. DHFS has made several visits, most recently on August 19, 2003, to this property and the surrounding neighborhood in coordination with discussions involving various stakeholders in the future of the JCI property. Meetings were held with WDNR, the Milwaukee Department of Public Health, the City of Milwaukee Redevelopment Commission, and with Johnson Controls and their consultants. To date, DHFS involvement has not included public health education or outreach activities, although the Milwaukee Health Department has a history of community involvement regarding the remediation and redevelopment of this property.
Interpretation of Environmental Investigation. DHFS reviewed volatile organic compound (VOC) data collected from groundwater monitoring wells around JCI property and interpreted these data using guidance from DHFS (2003) and the U.S. Environmental Protection Agency (EPA 2002). Based on these data alone, the potential for vapors of organic compounds to migrate from groundwater on the JCI property through soil spaces and into the basements of nearby residences cannot be eliminated. High concentrations of tetrachloroethene, trichloroethene, cis-1,2-dichloroethene, and xylenes were detected in groundwater samples collected around the west and south sides of the JCI property (Table 1).
Table 1. Concentration of major groundwater contaminants near the perimeter of the JCI Badger Facility, Milwaukee, WI 1.
| Contaminant | Maximum concentration detected in groundwater (ppb) | EPA vapor intrusion groundwater screening value2 (ppb) | EPA target indoor air concentration3 (ppb) |
EPA basis of target concentration |
| tetrachloroethene | 54,000 | 5 | 0.12 | Cancer risk |
| trichloroethene | 900 | 5 | 0.0041 | Cancer risk |
| cis-1,2-dichlorethene | 96,000 | 210 | 8.8 | Non-cancer risk |
| m-xylene | 162,000 | 23,000 | 0.0016 | Non-cancer risk |
1Results reported by Mongomery Watson Harza. Supplemental Groundwater Investigation Report, Johnson Controls Inc- Badger Facility. 2001 and by Earth Tech/Weston. 17 April 2003. Subsurface investigation work plan, former Badger Facility property, Johnson Controls, Inc.
2Acute minimal risk level
3Value satisfies both risk = 10-6 and hazard index = 1. U.S. EPA. 2002. Draft guidance for evaluating the vapor intrusion to indoor air pathway from groundwater and soils. Table 2c
ppb: parts per billion, or micrograms per liter
EPA (2002) has published model-based guidance and screening values for evaluating VOC migration and vapor entry into buildings. The EPA screening values for tetrachloroethene, trichloroethene, cis-1,2-dichloroethene, and m-xylene in groundwater are 5.0, 5.0, 210, and 23,000 µg/L, respectively (U.S. EPA 2002, table 2c). These numbers are modeled groundwater concentrations corresponding to indoor air concentrations that represent an increased lifetime cancer risk of one-in-one million. These screening values are exceeded for one or more of these VOCs at eleven monitoring wells on the west and south sides of the JCI property. The maximum groundwater concentrations summarized by Earth Tech (2003; figure 2-5) and Montgomery Watson Harza (2001) are tetrachloroethene: 54,000 micrograms/liter (µg/L); cis-1,2-dichloroethene: 96,000 µg/L; trichloroethene: 900 µg/L; and xylenes: 162,000 µg/L (table 1). Each of these monitoring wells lies within 100 feet of houses along Bremen Street or Auer Avenue. At several monitoring wells placed closer to these houses, private consultants report no detection of these VOCs. However, the ability of these vapors to migrate above the water table in directions contrary to groundwater flow, combined with the high concentrations present at the source areas, do not support a conclusion that the pathway is incomplete.
Based upon the EPA tiered approach to evaluating vapor intrusion, secondary screening (tier 2) for soil gases near the target residences is appropriate. The vapor intrusion pathway should be formally investigated as part of the scope of work at this site. Any future sampling should keep in mind that VOCs such as tetrachloroethene and trichloroethene do not necessarily follow groundwater movement, may travel long distances, and may travel in preferential pathways formed by utility trenches. In order to confidently rule out the effects of vapor intrusion on buildings, it is best to obtain either soil gas measured as close as possible to the target building or air samples within the target buildings. These measurements estimate vapor intrusion more realistically than groundwater samples.
In any environmental health review, consumption of contaminated groundwater and contact with contaminated soils are exposure pathways to consider. Around the JCI property, all residents use municipal water supplies, excluding consumption of contaminated groundwater as an exposure pathway. A review of previous investigations (Earth Tech 2003) qualitatively mentions metals in soils, as well as quantitative summaries of VOC contaminants in soils 2-6 feet below the surface. Clean overfill and sod were placed on the property through past remedial efforts, and the property is surrounded by a secure fence; therefore, there is little possibility of direct contact with contaminated soils. As a result, contaminants in surface soils at the site do not pose a human health concern. However, this issue should be revisited at such time that the property is redeveloped.
Review of Investigative Workplan. DHFS, working with WDNR, reviewed the investigative workplan submitted by JCI's consultant (Earth Tech 2003). The plan proposes to supplement existing site data with soil gas, groundwater, and soil sample collection points in order to better define the extent of soil and groundwater contamination and to assess whether completed soil vapor pathways to potential receptors exist.
The Investigative Work Plan describes vapor sampling points located west of Bremen Street that are intended to assess vapor movement away from the vadose zone source (that is, contaminants in the layer of unsaturated soil overlying the water table) or from contaminated groundwater. In an urban environment such as this one, it is important to understand the effect of utility corridors, either as an intercept of vapor migration or as a preferential pathway of vapor migration to nearby buildings. With that in mind, discussions with Johnson Controls during the design phase of the investigative work plan included the recommendation to sample over sewer laterals. Later, exploratory excavation of unused sewer laterals along Weil Street, to the east of the Johnson Controls property, revealed native backfill around sewer pipes, with no discoloration or spaces to suggest a preferential pathway. Consequently, Johnson Controls' consultants placed temporary soil vapor sampling points adjacent to nearby homes without regard to the location of sewer laterals. The interpretation of these soil vapor sample results should consider that frequent water entry into basements near sources of VOC contamination may preclude ruling out vapor intrusion merely by comparing soil gas samples to screening values. If frequent water entry into basements is identified, then it may be necessary to also test shallow groundwater or indoor air. If building-specific factors make the use of soil gas attenuation factors (and thus EPA screening values) inappropriate, it would be more effective to obtain direct evidence of soil gas impacts to adjacent residences through sub-slab gas probes. Although obtaining this information involves entry into houses, the direct information obtained does not require modeling or extrapolation to interpret data. Vapor migration will continue to be an issue at the JCI site as long as the source is present.
Of the chemicals detected in groundwater around the JCI property, tetrachloroethene (PCE) and trichloroethene (TCE) are of particular interest in evaluating the vapor intrusion pathway. This is due both to their physical behavior when dispersing in the environment, as well as their chemical behavior as it affects toxicity. To date, no data have been collected around the JCI property indicating that people have been exposed to TCE or PCE in their indoor air. Therefore, no health effects related to these chemicals can be predicted. A general discussion of the toxicology of those contaminants is provided in Appendix I.
Long-term exposure to chlorinated solvents and other volatile organic compounds in indoor air is a risk to child health. An investigation of the vapor intrusion pathway is needed to assess whether such a risk exists for children living in homes adjacent to the Johnson Controls property.
Robert Thiboldeaux, Ph.D.
Toxicologist
Health Hazard Evaluation Unit
Bureau of Environmental Health
Division of Public Health
Wisconsin Department of Health and Family Services
Earth Tech/Weston. 17 April 2003. Subsurface investigation work plan, former Badger Facility property, Johnson Controls, Inc.
Montgomery Watson Harza. Supplemental Groundwater Investigation Report, Johnson Controls Inc-Badger Facility. 2001.
U.S. EPA. 2002. Draft guidance for evaluating the vapor intrusion to indoor air pathway from groundwater and soils. http://www.epa.gov/correctiveaction/eis/vapor.htm 
DHFS [Wisconsin Department of Health and Family Services]. 2003. Chemical vapor intrusion and indoor air: Guidance for environmental consultants and contractors. http://www.dhfs.state.wi.us/eh/Air/
ATSDR [Agency for Toxic Substances and Disease Registry]. 2003. Air comparison values. Atlanta: US Department of Health and Human Services.
This public health consultation for the former Johnson Controls-Badger Facility was prepared by the Wisconsin Department of Health and Family Services under a cooperative agreement with the Agency for Toxic Substances and Disease Registry (ATSDR). It is in accordance with approved methodology and procedures existing at the time the Public Health Consultation was begun.
Gail Godfrey
Technical Project Officer, S.P.S., SAAB, DHAC
The Division of Health Assessment and Consultation, ATSDR, has reviewed this Public Health Consultation and concurs with the findings.
Roberta Erlwein
Chief, State Program Section, DHAC, ATSDR
APPENDIX I: TOXICOLOGY OF TETRACHLOROETHENE AND TRICHLOROETHENE
In many cases, the metabolism of foreign chemicals in the body does not lead to detoxication. Instead, chemicals may be biotransformed by specific metabolizing enzymes to forms that are harmful. Tetrachloroethene and trichloroethene are examples of chemicals that are metabolized by CYP2E1, an oxidizing enzyme, to a highly reactive intermediate form. Most of these reactive intermediates are further metabolized to a less toxic form, but a percentage of the reactive molecules damage large cellular molecules, such as proteins or DNA. Although the body is routinely able to repair most of this damage, some level of exposure leads to cell death, tissue damage, or an increased risk of tumor formation. Some whole-body effects reported from exposure to these chemicals include immune suppression, liver damage, and kidney damage. The Agency for Toxic Substances and Disease Registry (ATSDR) lists trichlorethene as a probable human carcinogen with an intermediate minimal risk level (MRL) in air of 100 parts per billion, and an acute MRL of 2000 parts per billion (ATSDR 2003). The carcinogenicity of tetrachlorethene is under review as of September 2003. The acute MRL of this chemical in air is 200 parts per billion.
