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 WisconsinDepartment of Natural Resources (WDNR), the Milwaukee Department of Public Health, andthe Milwaukee Redevelopment Authority to assess possible vapor intrusion of chlorinatedsolvents from the former Johnson Controls Inc.-Badger Facility (JCI) into the basements ofnearby private residences. Groundwater monitoring and soil sampling conducted on JCI andadjacent property indicates that volatile organic compounds (VOCs) on this site are sufficientlyconcentrated to present a potential vapor intrusion threat to nearby residences. The remediationof this property is currently being planned. The vapor intrusion pathway is being formallyinvestigated and addressed as part of the scope of work at this site. Vapor migration will be anissue 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.
This public health consultation summarizes the DHFS review of site information and documentspertaining to environmental investigation and remediation work at the former Johnson Controlsfacility in Milwaukee, Wisconsin. DHFS recommendations have been incorporated into ongoinginvestigation at this property.
The former Johnson Controls facility is located at 3238 N. Bremen, Milwaukee. The property iscurrently a fenced, grass-covered, 2.8 acre vacant lot surrounded by an older (1930-1940shousing stock) residential neighborhood. The property had been used for storage andmanufacturing since 1910, including the manufacture of radio components by Globe Union Inc.from 1944 to the 1970s (Earth Tech, 2003). Environmental investigations beginning in 1992report the presence of volatile organic compounds, most significantly xylenes, tetrachloroethene,cis-1,2-dichloroethylene, trichloroethene, and petroleum-related compounds in soil andgroundwater on the property. Since 1998, all buildings and surface structures have beenremoved from the property. In 1999, 9,115 tons of soils contaminated with chlorinated solventswere excavated and thermally treated on-site. Presently, consultants representing JCI haveproposed an investigative work plan (Earth Tech 2003). Part of the 2003 investigative work planis directed toward ruling out the potential for vapor intrusion into nearby homes and towardestablishing the property as suitable for residential redevelopment. At the request of WDNR,DHFS reviewed the investigative work plan proposed for the former JCI-Badger Facilityproperty.
Site visit. DHFS has made several visits, most recently on August 19, 2003, to this property andthe surrounding neighborhood in coordination with discussions involving various stakeholders inthe future of the JCI property. Meetings were held with WDNR, the Milwaukee Department ofPublic Health, the City of Milwaukee Redevelopment Commission, and with Johnson Controls and their consultants. To date, DHFS involvement has not included public health education oroutreach activities, although the Milwaukee Health Department has a history of communityinvolvement 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 interpretedthese 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 tomigrate from groundwater on the JCI property through soil spaces and into the basements ofnearby residences cannot be eliminated. High concentrations of tetrachloroethene,trichloroethene, cis-1,2-dichloroethene, and xylenes were detected in groundwater samplescollected around the west and south sides of the JCI property (Table 1).
|Contaminant||Maximum concentration detected in groundwater (ppb)||EPA vapor intrusion groundwater screening value2 (ppb)||EPA target indoor air concentration3 |
|EPA basis of target concentration|
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 beformally investigated as part of the scope of work at this site. Any future sampling should keepin mind that VOCs such as tetrachloroethene and trichloroethene do not necessarily followgroundwater movement, may travel long distances, and may travel in preferential pathwaysformed by utility trenches. In order to confidently rule out the effects of vapor intrusion onbuildings, it is best to obtain either soil gas measured as close as possible to the target building orair samples within the target buildings. These measurements estimate vapor intrusion morerealistically than groundwater samples.
In any environmental health review, consumption of contaminated groundwater and contact withcontaminated soils are exposure pathways to consider. Around the JCI property, all residentsuse municipal water supplies, excluding consumption of contaminated groundwater as anexposure pathway. A review of previous investigations (Earth Tech 2003) qualitativelymentions metals in soils, as well as quantitative summaries of VOC contaminants in soils 2-6feet below the surface. Clean overfill and sod were placed on the property through past remedialefforts, and the property is surrounded by a secure fence; therefore, there is little possibility ofdirect contact with contaminated soils. As a result, contaminants in surface soils at the site do notpose a human health concern. However, this issue should be revisited at such time that theproperty is redeveloped.
Review of Investigative Workplan. DHFS, working with WDNR, reviewed the investigativeworkplan submitted by JCI's consultant (Earth Tech 2003). The plan proposes to supplementexisting site data with soil gas, groundwater, and soil sample collection points in order to betterdefine the extent of soil and groundwater contamination and to assess whether completed soilvapor pathways to potential receptors exist.
The Investigative Work Plan describes vapor sampling points located west of Bremen Street thatare intended to assess vapor movement away from the vadose zone source (that is, contaminantsin the layer of unsaturated soil overlying the water table) or from contaminated groundwater. Inan urban environment such as this one, it is important to understand the effect of utilitycorridors, either as an intercept of vapor migration or as a preferential pathway of vapormigration to nearby buildings. With that in mind, discussions with Johnson Controls during thedesign phase of the investigative work plan included the recommendation to sample over sewerlaterals. Later, exploratory excavation of unused sewer laterals along Weil Street, to the east ofthe Johnson Controls property, revealed native backfill around sewer pipes, with nodiscoloration or spaces to suggest a preferential pathway. Consequently, Johnson Controls'consultants placed temporary soil vapor sampling points adjacent to nearby homes withoutregard to the location of sewer laterals. The interpretation of these soil vapor sample resultsshould consider that frequent water entry into basements near sources of VOC contaminationmay preclude ruling out vapor intrusion merely by comparing soil gas samples to screeningvalues. If frequent water entry into basements is identified, then it may be necessary to also testshallow groundwater or indoor air. If building-specific factors make the use of soil gasattenuation factors (and thus EPA screening values) inappropriate, it would be more effective toobtain 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 obtaineddoes not require modeling or extrapolation to interpret data. Vapor migration will continue to bean issue at the JCI site as long as the source is present.
Of the chemicals detected in groundwater around the JCI property, tetrachloroethene (PCE) andtrichloroethene (TCE) are of particular interest in evaluating the vapor intrusion pathway. Thisis due both to their physical behavior when dispersing in the environment, as well as theirchemical behavior as it affects toxicity. To date, no data have been collected around the JCIproperty 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 isa risk to child health. An investigation of the vapor intrusion pathway is needed to assesswhether such a risk exists for children living in homes adjacent to the Johnson Controls property.
- At the JCI property, chlorinated solvents are sufficiently concentrated in subsurface soils andgroundwater to potentially cause vapor migration through soils and into nearby buildings.Therefore, the site poses an indeterminate public health hazard.
- Vapor migration will continue to be an issue at the JCI site as long as the source is present
- Elevated levels of contaminants exist in sub-surface soils, where people do not have direct contact. Surface soils at the site are not impacted and do not pose a health concern unless redevelopment of the property brings people into direct contact with contamination.
- Groundwater affected by contaminants from the JCI property is not consumed as drinkingwater in this area. Therefore, there is no public health hazard from this exposure pathway.
- The extent of the remaining vadose zone source should be investigated as part of the scope of work at this site
- Cleanup of remaining contaminated soils on this property, particularly the source ofchlorinated solvents, should be considered in order to address future on- and off-site health hazards.
- On-site surface soils should be investigated for the presence of metals prior to anyredevelopment construction.
- DHFS will evaluate the results of the vapor intrusion investigation and assess the potential for a completed exposure pathway.
- The Responsible Party has contracted to investigate vapor migration around the JCI site. The extent of vapor migration into the adjacent residential neighborhood is being formally investigated as part of the scope of work for this site.
- The results of the investigation will be discussed with area residents.
Robert Thiboldeaux, Ph.D.
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, JohnsonControls 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 bythe Wisconsin Department of Health and Family Services under a cooperative agreement withthe Agency for Toxic Substances and Disease Registry (ATSDR). It is in accordance withapproved methodology and procedures existing at the time the Public Health Consultation was begun.
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.
Chief, State Program Section, DHAC, ATSDR
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.