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The construction of a railroad underpass, planned in Marshfield, Wisconsin, willencounter coal tar wastes remaining from a manufactured gas plant (MGP) formerlylocated adjacent to the underpass site. Environmental health hazards include the potentialrelease of MGP-related volatiles and dust to ambient air, the accumulation of polycyclicaromatic hydrocarbons (PAHs) on soils of nearby residences and playgrounds, potentialeffects to the aquifer used by the Marshfield municipal water utility, and potentialexposure related to the underpass lift station. A site management plan is recommendedthat includes monitoring and control of dust, PAHs, and volatile hydrocarbons. DHFSalso recommends that the ABC Childcare Center be relocated during the removal ofMGP waste, that the surrounding aquifer be monitored for long-term effects to theregional water supply, and that water and gases at the underpass lift station be monitoredfor volatile contaminants.


The Wisconsin Department of Health and Family Services, Division of Public Health(DPH), was asked by the Wisconsin Department of Natural Resources (WDNR) forassistance in assessing public health hazards associated with the construction of arailroad underpass in Marshfield, Wood County, Wisconsin. The underpass will passbeneath the Soo Line Railroad at its intersection with Peach Avenue (figure 1). Theunderpass is a joint project of Marshfield and the Wisconsin Department ofTransportation (DOT), and is scheduled to begin early in 2003. Environmentalassessments of the site (Dames & Moore 2000; RMT 2002) suggest that the work willencounter coal tar wastes remaining from a manufactured gas plant (MGP) formerlylocated adjacent to the underpass site. Potential environmental health hazards stem fromthe plan to excavate these coal tar wastes found in soil and groundwater near the railroad-Peach Avenue intersection. The environmental health issues and plans to partiallyremediate this former MGP site were described in a previous ATSDR Public HealthConsultation (Thiboldeaux, 2002). During the spring of 2002, this MGP site waspartially remediated by the energy utility company that owns the property. At that time,coal tars, buried structures, and contaminated soil beneath the Peach Avenue MGP sitewere removed.

As described previously (Thiboldeaux, 2002), the surrounding area is a residentialcommunity bisected by a wide industrial and railroad corridor (figure 1). The underpasssite lies within this corridor. A residential neighborhood of mostly single-family housesis located to the north across Arnold Street. Pickle Pond Park, a playground, is northeastof the site across Peach Avenue. Adjacent to, and north of, the former MGP site are abuilding supply company and a child care center (figure 1). Vacant lots and residentialneighborhoods lie further west of the site. The residential and working population isestimated from maps (Dames & Moore 2000) to be 100-150 people within a 100-yardradius, and 400-550 people within 300 yards.

Public Health Issues

Discussions in this public health consultation include those on several aspects of thePeach Avenue underpass project anticipated to be potential health issues as this workproceeds. These are:

  • Potential release of MGP-related volatiles and dust to ambient air.
  • Accumulation of polycyclic aromatic hydrocarbons (PAHs) on soils of nearbyresidences, playgrounds, and the childcare center yard.
  • Potential effects to the aquifer used by the Marshfield municipal water utility.
  • Potential exposure related to the underpass lift station.


Potential release of MGP-related volatile organic compounds to ambient air. Soilcontaminants detailed in the Laboratory Analysis Reports and Summaries (RMT, 2002)indicate that coal tars remain in areas to be excavated within Peach Avenue. The mostconcentrated areas, containing benzene, naphthalene, benzo(a)pyrene, and other coal tarcomponents (table 1), are near the buried structure removed by NiSource in 2002. Lowerconcentrations of coal tars were detected in adjacent soil areas (RMT 2002, data notshown). Previous experience at this and other MGP sites predicts that air releases willoccur during excavation and removal of coal tars. In the interest of public health, theDOT workplan should include means to monitor and manage such air releases (seeThiboldeaux and Nehls-Lowe, 2002). MGP wastes contain mixtures of compounds, eachhaving varying properties of vapor pressure, olfactory sensitivity, and toxicity. Odorsreleased from MGP excavation sites are often regarded as nuisances. However, it isimportant to recognize that smelling an odor also represents a legitimate and verifiableinhalation exposure, the effects of which depend upon the concentration and the toxicmechanism of the substance inhaled. Several volatile compounds which may beencountered during excavation at this site, including benzene, naphthalene, and toluene,may cause acute health effects such as dizziness or nausea. Benzene, which will beencountered in high concentration at some locations on site (table 1), is also an EPAclass-A carcinogen.

The nearby receptors for potential air impacts are the children and workers at ABCChildcare Center, as well as people at other nearby businesses and houses. As during theprevious round of excavation, the ABC Childcare Center should be temporarily relocatedduring that portion of the underpass project in which coal tar will be encountered. During the previous (2002) excavation, site visits and reports from neighbors indicatedthere were occasional air releases sufficient to cause health effects such as eye and throatirritation in the nearby neighborhood. This was observed even though the workemployed state-of-the-art air control techniques. In the case of the underpass work,should the prediction of less coal tar and petroleum contamination prove true, then theremoval of these materials should proceed smoothly, and the length of the relocation canbe shortened. No one can predict with certainty the risks associated with encounteringchemical hazards during the planned excavation. However, moving the childcare centerin advance will avoid unplanned, costly delays and other problems caused by extendedair releases from unexpected contaminants. Given the uncertainty in the degree ofcontamination, DHFS considers these recommendations prudent.

Air deposition of polycyclic aromatic hydrocarbons (PAHs) on soils of nearbyresidences, playgrounds, and daycare yard. The PAHs are another group of compoundspossessing harmful effects and having the potential for dispersal from this site. Some ofthese compounds are semi-volatile; others sorb to soil particles. When soil particles aredispersed as dust, humans may be exposed via inhalation or through direct contact withdust deposits. The tent structure used during the 2002 removal at this site adequatelyprevented dust dispersal and provided the basis of our public assurance that PAHs hadnot contaminated the adjacent child care center property. We would like to be able toprovide a similar level of public health assurance during the proposed underpass project. Although an enclosed tent structure provides optimal conditions for air qualitymanagement, other contractors specializing in MGP remediation in Wisconsin have hadsuccess with surfactants or foams for dust and odor control. The placement of plasticsheeting may be sufficient under many circumstances but has the shortcoming of beinglabor intensive. Also, we have seen elsewhere that plastic is prone to failure when it isneeded most, namely during high winds and heavy rains. Once one corner anchor of theplastic sheets fails in wind, the rest follows. The time and labor required to place thesheet each morning and evening, as well as during the day when needed, should be cost-balanced against the more effective and less labor-intensive foam or surfactantalternatives.

Potential effects to the aquifer used by the Marshfield Municipal Water Utility. Much ofthe coal tar contaminants in and near the underpass site were removed in 2002. Additional contaminants will be removed during the underpass construction. However,previous study (Dames & Moore, 2000) suggests that after this completed and scheduledremoval of MGP wastes, coal tars below 25 feet deep and a soil and groundwater plumeof MGP wastes will remain in the neighboring area. Concerns have been raised by ahydrogeological consultant for the city (Janzen, 2002), that these remaining contaminantswill threaten the sole aquifer for the Marshfield municipal water supply. According topublished water quality results (WDNR 2002), MGP-related VOCs are not currently ahealth threat in the Marshfield water supply. The incomplete removal of MGP wasteprior to commencing the underpass construction may inhibit future remediation needed toprotect groundwater. DHFS agrees that because this plume is incompletelycharacterized, the potential threat to the Marshfield municipal aquifer is an unansweredquestion that should be monitored. In addition, city officials should discusscontingencies for alternative or treated water sources should the aquifer eventuallybecome unsafe.

Potential exposure related to the underpass lift station. The underpass plans call for theinstallation of a lift or pumping station in the underdrain system beneath the underpass. The pumping station, as described, will consist of a concrete-walled man hole, normallyused to collect storm water, that will also have a pump in the bottom to lift collectedgroundwater to the sanitary sewer for discharge. The highway underdrain system will beshunted to this man hole for the collection and discharge of contaminated groundwater. There is an unknown potential for organic contaminants in the groundwater collected atthe pumping station to volatilize and release contaminants to air. The potential for thesereleases depends upon both the concentration of individual compounds in collectedgroundwater and the vapor pressure (potential to volatilize) of individual compounds. Exposure to volatile contaminants at this source could be brief and intermittent, such asto people working or passing near the lift station. Exposure could also be chronic, wherevolatiles in storm water might enter homes downstream of the lift station via dry P-trapsin basement drains. At this time it is not possible to predict a health threat from thissource without knowing the concentration of volatile contaminants in groundwatercollected at the lift station, as well as knowing design details of the lift station.

Public outreach. Past community involvement activities related to this project havedemonstrated strong local public interest. DHFS recommends outreach designed toinform the public of the environmental health effects of the proposed work. It has beenour experience that information provided well in advance of the construction start date,along with a meeting for public discussion, is essential in the public's acceptance of theproject. The information provided should include a project overview, contaminants ofconcern, the effects of noise and dust, truck routes, and expected project dates. In thecase of the Peach Avenue underpass, outreach should emphasize outcomes of improvedpublic safety, such as better emergency vehicle access and traffic flow. Residents shouldalso be given telephone numbers for key people within the project should they havequestions or need to report problems.


The daycare center located adjacent to the Columbia Propane property presents obviousconcerns that children and adults at this facility will be affected by the plannedremediation of the Marshfield former MGP. Hazards associated with the MGPremediation include the potential for inhalation exposure to VOCs and the associatedpossibility of respiratory distress, especially in asthmatic children. PAHs sorbed to soildust may be released to air during soil removal, and may be deposited on surfacesthroughout the daycare facility and surrounding playgrounds. The daycare center shouldbe considered to lie within the air impact zone and possibly the health and safetyexclusion zone for some phases of this work. Therefore, temporary relocation of thedaycare center during the MGP remediation is recommended. In addition, efforts shouldbe made to avoid the deposition of PAH-containing particles on or around the daycarecenter. Part of the MGP site remedy should include monitoring for PAHs and plans toremove PAHs from indoor or outdoor surfaces should they be detected at unsafeconcentrations.


  • Coal tar impacts remain in areas to be excavated within Peach Avenue, particularlynear the area of the buried structure removed in 2002.
  • A health risk is posed by the potential of an uncontrolled release of volatile,semivolatile, and particulate organic compounds, to ambient air, during the excavation ofthis MGP waste site.
  • MGP wastes remaining in the area are an incompletely characterized threat to theMarshfield municipal aquifer.
  • The potential release of volatile contaminants from the proposed underpass lift stationpresents an uncharacterized health risk from inhalational exposure to VOCs.


  • DHFS recommends that the city and DOT develop a detailed workplan to monitorand control airborne releases of dust, PAHs, and volatile organic compounds found incoal tar.
  • The ABC Childcare Center should be temporarily relocated during the removal ofMGP waste.
  • In order to provide pubic health assurance from the presence of accumulated PAHs inand around the childcare center, DHFS recommends that the work plan include plans toeither place tarp covers on the child care center playground, followed by interior andexterior washing of the building and playground. An alternative would be to monitor theproperty for PAH deposition, then clean the property if monitoring indicated this wasnecessary.
  • DHFS recommends that the surrounding aquifer be monitored for long-term effectsto the regional water supply.
  • DHFS recommends that the underpass lift station be designed to addresscontaminants in water and related vapors likely to be encountered. Some long termmonitoring may also be appropriate.
  • DHFS recommends that attention be placed on public outreach designed to inform thepublic of the environmental health effects of the proposed work.


  • During the construction phase of the Peach Avenue underpass, ambient airmonitoring will be conducted by DOT's environmental consultant or contractor.
  • The city of Marshfield has agreed to administer the temporary relocation of the ABCChildcare Center.
  • WDNR will identify a responsible party and administer the placement of groundwaterwells needed for long-term monitoring of the local aquifer.
  • DHFS will work with the city of Marshfield and WDNR to implement monitoring, ifappropriate, of volatile contaminants in storm water at the underpass lift station.
  • Prior to beginning the construction phase of the Peach Avenue underpass, the city ofMarshfield will conduct public outreach that will address environmental health issuesassociated with this work. DHFS and Wood County Health Department will participateand provide health information to residents with concerns or questions.


Dames & Moore Group Company. Final Report, Supplemental Site Investigation, andEvaluation of Remedial Alternatives for the Peach Avenue Former MGP Site,Marshfield, Wisconsin. Proj. no. 41384-019-133. June 2, 2000.

Jansen, John, Aquifer Science & Technology. July 3, 2002 letter to Joseph Pacovsky,Marshfield Electric & Water Dept regarding potential effects of Peach Street MGP siteon regional aquifer.

RMT Inc. Laboratory Analysis Reports and Summaries. WI Dept. Transportation no.1623-09-74. July 30, 2002.

RMT Inc. Amendment to Materials Handling Plan. WI Dept. Transportation no. 1623-09-74. July 30, 2002.

Thiboldeaux, R. Public Health Consultation for Columbia Propane, Marshfield, WoodCounty, Wisconsin. WI Dept. Health and Family Services, under cooperative agreementwith the Agency for Toxic Substances and Disease Registry. July 6, 2002.

Thiboldeaux, R., and Nehls-Lowe, H. Interim Guidance on Air Management at FormerManufactured Gas Plant Sites. January 25, 2002 Memorandum to Mark Giesfeldt,Bureau of Remediation and Redevelopment, Wisconsin Department of NaturalResources.

Wisconsin Department of Natural Resources. 2002. Drinking Water System Database. Available: Exiting ATSDR Website


Robert Thiboldeaux, Ph.D.
Health Hazard Evaluation Unit
Bureau of Environmental Health
Division of Public Health
Wisconsin Department of Health and Family Services.


This public health consultation for the Peach Avenue Railroad Underpass investigationwas prepared by the Wisconsin Department of Health and Family Services under acooperative agreement with the Agency for Toxic Substances and Disease Registry(ATSDR). It is in accordance with approved methodology and procedures existing at thetime the Public Health Consultation was begun.

Gail D. Godfrey
Technical Project Officer, S.P.S., SAAB, DHAC

The Division of Health Assessment and Consultation, ATSDR, has reviewed this PublicHealth Consultation and concurs with the findings.

Lisa C. Hayes
for Chief, State Program Section, DHAC, ATSDR

Table 1.

Selected hydrocarbons detected in soil beneath Peach Avenue in proposed excavation area, August 1998 survey.1
Substance maximum conc. detected
Comparison value
benzene 350,000a 500b, A c
toluene 3,300 a 520,000 b
dibenzo(a,h)anthracene 2,600,000 a 7200 b, B2c
benzo(b)fluoranthene 1,100,000 a 23,000 b, B2 c
chrysene 2,500,000 a 3600 b, B2 c
fluoranthene 5,500,000 a 68,000 b
fluorene 7,300,000 a 89,000 b
naphthalene 33,000,000 a 180,000 b
pyrene 8,200,000 a 56,000 b
phenanthrene 15,000,000 a Unlisted
benzo(a)pyrene 2,300,000 a 11,000 b, B2 c

1 RMT Inc. Laboratory Analysis Reports and Summaries. July 30, 2002.
a Sample location: Soil boring SB-4A, middle of present Peach Avenue near buried structure removed by NiSource (fig. 1).
bUSEPA, Region III Risk-based concentration, transfer from soil to air. This value illustrates the most probable exposure route for the contaminants listed.
cUSEPA cancer classification.

Site of proposed Peach Avenue Underpass and vicinity, Marshfield, Wisconsin
Figure 1. Site of proposed Peach Avenue Underpass and vicinity, Marshfield, Wisconsin.

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