Skip directly to search Skip directly to A to Z list Skip directly to site content


Coal Tar Contamination Associated with a Former Manufactured Gas Plant



The Ashland/Northern States Power (NSP) Lakefront site has extensive contamination of soils,groundwater, and offshore sediments associated with manufactured gas plant (MGP) operationshistorically conducted at the site. The primary contaminates are polycyclic aromatichydrocarbons (PAHs) and volatile organic compounds (VOCs). The following points arenoteworthy:

  • Exposure to contaminated sediments in Chequamegon Bay are a human health hazard. People should not swim or wade in contaminated areas. Warning signs and the no-anchor zone should remain.

  • During the cleanup of the site, vapors can escape into air and pose a human health hazard. Stringent air management is crucial during cleanup.

  • Contact with coal tar slicks may cause skin and eye irritation. People who get coal tar on their skin should immediately wash the area with soap and warm water. If coal tar gets into eyes, they should be flushed with water.

  • The water from two artesian wells at Kreher Park is safe to drink, but the wells should continue to be regularly tested for site-related contaminants.

  • Sport caught fish from Chequamegon Bay do not contain levels of site-related chemicals that are a health concern for eating. However, people who eat Lake Superior fish should follow the Department of Natural Resources (DNR) fish consumption advisory for other chemicals.

  • The testing of the indoor air of homes close to site should be considered in order to evaluate the possibility of vapors that may enter basements.


The purpose of this public health assessment is to evaluate contamination exposure concerns thatare apparently associated with manufactured gas plant (MGP) operations historically conductedin Ashland, Wisconsin. The scope of the evaluation includes the human health implications ofexposure to environmental contamination and the related community health issues. Thisdocument contains results of a review of three previous public health consultations and baselinesampling data of soil, groundwater, and offshore sediments related to the human health riskassessment. The prior public health consultations documented the evaluation of human healthconcerns associated with contamination in Chequamegon Bay sediments, the safety of sport fishcaught from the bay, and air concerns during the investigation and cleanup of the site.


A. Location and Population

The city of Ashland is in Northwestern Wisconsin on Chequamegon Bay, Lake Superior (Figure1). It has a population of 8,620 and is the largest city in Ashland County. Ashland County has apopulation of 16,866; nearby communities include the Bad River Indian Reservation (1,400), andthe towns of Sanborn (1,092), and White River (796). Across the Bay is the city of Washburn(2,303), in Bayfield County. Washburn is the largest city close to Ashland.1

Chequamegon Bay, Western Lake SuperiorCensus estimates show that the area's population has not changed much since 1990. AshlandCounty grew by 3.3 percent between 1990 to 1999 (16,307 to 16,866). The city of Ashlanddropped in population by 0.86 percent (8,695 to 8,620) during the same time period. The entirearea has had limited populationgrowth for the past 20 years. Thepopulation distribution for AshlandCounty shows that one-third (31%)is under 20 years of age; 53% is 20-64 years; 16% is 65 and older. Unemployment between 1990 to1999 ranged between 6.5% and8.5%. Ashland's ethnic profileshows that approximately 90% of thepopulation is white; 10% is NativeAmerican. Females slightlyoutnumber males, 51% to 49%,respectively.2,3

B. Site Description

The Ashland/Northern States Power (NSP) Lakefront site is located in Ashland, Wisconsin. Thesite is bordered by US Highway 2 to the south, Prentice Avenue to the east, Ellis Avenue to thewest, and Chequamegon Bay to the north. The properties on which contamination is locatedencompass approximately 12 acres and from south to north includes Northern States PowerCompany (now referred to as Xcel Energy), Wisconsin Central Limited Railroad corridor, City ofAshland's old waste water treatment plant/Kreher Park, and contaminated sediments inChequamegon Bay. The site encompasses contamination in two sources, sediments inChequamegon Bay, and areas where contamination has migrated as a result of activitiesapparently associated with MGP operations historically conducted at the Xcel Energy propertyabove the bluff.4

Currently, Kreher Park is owned by the City of Ashland. Kreher Park is used for a variety ofrecreation purposes. A lakefront bicycle path runs along the shoreline at the Park. A largeportion of the Park is flat and is covered with grass. The shoreline immediately in front ofKreher Park consists mostly of large rocks, installed as riprap, to protect the integrity of theshoreline. Yellow warning signs are placed every 100 feet that warns the public aboutcontaminated sediments. Along the northeastern shoreline of Kreher Park is the large brickbuilding that housed Ashland's former waste water treatment plant. Large, privately owned boatsare stored along the southwestern edge of the grassy area. Connected to the northwestern portionof Kreher Park is the Ashland Marina, which was developed in the 1980s.

Along the eastern boundary of Kreher Park is a boat ramp, public swimming beach, and acampground. The waters of Chequamegon Bay that are directly in front of Kreher Park, arebounded to the northeast and southwest by a number of old docks, which partially protect the park shoreline. The strongest onshore winds in the Ashland area come from the northeast.

Ashland/NSP Lakefront Site, WisconsinApproximately one-quarter milenortheast of Kreher Park is a verylarge, historic ore dock. The ore dockserves as a significant outerbreakwater for the marina, includingKreher park, the boat ramp andswimming beach. The ore dockprotects this area from northeasterlywind and wave action.

C. What is a Manufactured Gas Plant?

Starting in the late 1800s, towns and cities across the U.S. made their own fuel for cooking andlighting. The facilities where the fuel was produced were known as manufactured gas plants(MGPs). To manufacture the fuel, coal and other ingredients were heated in large brick ovens. As the coal was heated, it produced gases which were filtered from the ovens and stored in tanks. The gas was then used as fuel throughout a community. By the early 1900s, Wisconsin hadMGPs in at least 70 communities across the state.

MGP production declined in the U.S. as electricity replaced coal gas for lighting. MGPs startedclosing as a network of natural gas pipelines was built across the country in the 1950s. ManyMGPs were abandoned and eventually demolished. However, waste and contamination leftbehind at MGPs can still pose an environmental and public health concern.

For more information about MGPs, visit the Division of Public Health Internet address below:

D. Site History

Prior to about 1880, the Ashland shoreline at Kreher Park was at the base of the bluff,approximately along the current Wisconsin Central Ltd. railroad corridor. Significantcommercial and industrial activities began at that time. The land where Kreher Park is nowlocated was created during the late 1800s and early 1900s when various fill materials were placedin Chequamegon Bay. Fill material that comprises the eastern portion of Kreher Park, consists ofmainly sawdust and wood waste that came from a series of sawmills which operated on the sitefrom the early 1880s until about 1932. The uncontrolled filling of the rest of this area occurredduring and after the operation of the sawmills, with the western portion of Kreher Park filled in with primarily demolition waste material.

From the 1880s through 1947, a manufactured gas plant operated on the property now owned byXcel Energy. A ravine ran north-south through the property, emptying into Chequamegon Bay. Historical maps show that the ravine was mostly open in the late 1800s, and was filled by theearly 1900s. Investigations have shown that the fill material includes cinders ash, boiler slag,demolition debris, household waste, and soil(1).

E. Environmental Investigations

Local officials notified the Wisconsin Department of Natural Resources (DNR) of contamination found in excavations around the wastewater treatment plant in the late 1980s. Subsequent investigations determined widespread VOC and PAH contamination on their property.

In 1993, DNR staff began investigating the contamination found on the city property usingmoney from the state's Environmental Fund. These investigations concluded that at least someof the contamination detected on city property was residuals from the historic manufactured gasplant that operated on the adjacent property.

In 1995, NSP was notified by the DNR as a Potentially Responsible Party (PRP) for thatcontamination (The City of Ashland and the Wisconsin Central Limited Railroad were alsonotified as potential PRPs). From 1995 until now, NSP and DNR have carried out investigationsof the site, and through these investigations, the degree and extent of soil, groundwater andsediment contamination have largely been determined. A Human Health Risk Assessment hasbeen completed for the site and an Ecological Risk Assessment for the sediments by DNRcontractors.6

In 1999, a citizen's petition requested that the U.S. Environmental Protection Agency (U.S. EPA) assess the site and determine if it should be listed on the Federal Superfund National PrioritiesList (NPL). At U.S. EPA's request, DNR prepared a preliminary assessment, which showedenough evidence for U.S. EPA officials to take the next step and do a more rigorous evaluationusing Superfund's Hazard Ranking System (HRS). Based on the HRS, the U.S. EPA proposedlisting the Ashland site on December, 2000. The U.S. EPA also agreed that the Wisconsin DNRwould be the lead agency supervising the cleanup of the Ashland site.

F. Contaminated Media

Environmental sampling data for the Ashland site (groundwater, soil, and sediments) that wascollected between 1994-1996 was compiled in the 1997 report Comprehensive EnvironmentalInvestigation Report by Short Elliott Hendrickson, Inc.7 Selected data from this report issummarized in the tables that appear in Appendix A. Additional environmental investigationshave been conducted at the Ashland/NSP lakefront site. However these reports have not resultedin significant changes to the original baseline human health risk assessment.

The subsurface soil, groundwater, lake sediments and surface waters at the Ashland/NSPlakefront site is contaminated by varying concentrations of complex mixtures of organicchemicals that are typical of a former MGP site. The largest group of MGP-related contaminantsare commonly grouped into two categories: 1) polycyclic aromatic hydrocarbons (PAHs); and, 2)volatile organic compounds (VOCs). When these MGP associated contaminants are found inthe environment at very high concentrations or in pure forms, they are not very soluble in waterand often appear as coal tars and oils. When pure coal tars or oils are found in the environmentthey are referred to as "free product" or, more technically, a non-aqueous phase liquid (NAPL). Sometimes a NAPL is heavier or more dense than water and sinks, sometimes a NAPL is lighterthan water and floats. The presence of NAPLs provides insight into determining the scope andnature of coal tar contamination.

The shallow groundwater in the vicinity of the former MGP site on the bluff and within the filledravine tends to move in a northerly direction and is very contaminated with PAHs and VOCs. Adeep aquifer (water bearing rock formation) beneath all portions of the site is referred to as theCopper Falls aquifer, which consists mainly of sand and gravel. This aquifer is separated fromshallow groundwater by a very thick and impervious layer of clay, which is referred to as theMiller Creek Formation.

A brief narrative of the site contamination by media, is listed below:

  1. Surface and Subsurface Soils
Initial Investigation of the Ashland/NSP Lakefront Site: 1980s - investigations by the City of Ashland revealed their property had widespread VOC and PAH contamination, 1980s - local officials notify DNR about contamination at the lakefront, 1993 - DNR begins investigating area; results reveal that some of the contamination comes from past activities at the MGP, 1995 - DNR notify NSP/Xcel Energy that they are a Potentially Responsible Party (PRP) for the site, 1995-2001 - DNR and NSP/Xcel Energy conduct numerous investigations, including ecological and health risk assessments. DNR concludes the  results reveal the site poses significant risks to human health and environment, but Xcel Energy disagrees with DNR's conclusion regarding the risk assessment.

Environmental sampling found widespread PAH and VOC contamination in subsurface soils at the lakefront and bluff area. The VOCs detected, namely the BTEX compounds (benzene, toluene, ethylbenzene, and xylenes), were found at elevated concentrations (Appendix A, Table 1). The concentrations of VOCs in subsurface soils were significantly higher in samples collected at Kreher Park than at the upper bluff area, e.g. the highest benzene levels found in subsurface soils at the lakefront was 645 parts per million (ppm); whereas for the upper bluff area it was 19.8 ppm. Despite these high levels, VOCs in subsurface soils do not pose a direct contact health concern. Surface soils typically pose the greatest exposure threat at contaminated properties, but clean fill soils are on top of affected subsurface soils at both the lower and upper portions of the site. Soils at Kreher Park were brought from an unknown location, but do not have elevated levels of contaminants and are safe. However, the fill material and groundwater beneath Kreher Park is affected by MGP associated contaminants similar to the filled-in ravine.

  1. Offshore Soil and Sediment

Chequamegon Bay sediments immediately off of Kreher Park contain MGP associatedcontamination (Table 2). Sediments in this area contain VOCs and PAHs, with high levelsof contamination or coal tar/NAPL, that is consistent with the rest of the site. For example,benzene was detected at a high range of 55,000 ppm, and a low range of 57 ppm; totalxylenes were detected at 590,000 ppm and a low of 43 ppm. One PAH, benzo(a)pyrene wasfound at a high of 49 ppm in offshore soil and sediment, 111 ppm at the upper bluff area, and206 ppm in sediments along the shoreline. While contamination exists mainly within thesediments, if the sediments are agitated, coal tars/NAPLs bound within sediments arereleased to the water column, enabling a "slick" to form on the water surface.

  1. Groundwater

Groundwater beneath the Ashland Lakefront/NSP site has a widespread variation in thelevels of VOCs and PAHs detected in both the shallow and deep aquifers and beneath boththe lakefront and bluff areas (Table 3 and Table 4). Portions of the Copper Falls aquiferthat are situated directly beneath the site also contains significant MGP associatedcontamination. A column of MGP associated contamination moved with the groundwaterflow to the north and towards Chequamegon Bay.

In many monitoring wells at the lakefront and upper bluff area VOC and PAH concentrationsexceed Wisconsin's Public Health Groundwater Quality Enforcement Standards (ES). Atcertain locations, concentrations of PAHs and VOCs in groundwater is very high and a "freeproduct" has been found in some samples. This "free product" or NAPL consists of oil, tarand other wastes characteristic of former manufactured gas plants. Sampling for NAPLs inthe groundwater column found free coal tar product ranging from 1 to 26 feet deep. NAPLswere found in soils far below the ground surface, ranging from 14 to 70 feet beneath thesurface. The most extensive NAPL contamination in groundwater was at the upper bluffarea; the least extensive areas of NAPL contamination was at the lakeshore.

Groundwater beneath the upper bluff area has a much higher VOC contamination than thelakefront, while the levels of PAHs is higher in groundwater at the lakefront. For example,benzene was detected at the highest level of 79,000 parts per billion (ppb) in the upper bluffarea; whereas the highest benzene level at the lakefront was 4,100 ppb. In contrast,benzo(a)pyrene was detected at a high of 3,278 ppb at the lakefront; and 898 ppb at the upperbluff area. The Wisconsin DNR enforcement standard (ES) for benzo(a)pyrene is 0.2 ppb.

  1. Surface Water Seep at Kreher Park

Near the point where the filled ravine previously emptied into the bay was an area wherewater, oils, and tars discharged to the surface, and where people could easily have contactwith contamination. Water samples collected directly from this area, known as "the seep"showed elevated concentrations of VOC and PAHs (Table 3 and Table 4).

G. Summary of Public Health Consultations

  1. Human Health Concerns Associated with Contaminated Sediments

The first public health consultation, written October 23 1995 by DPH, examined humanhealth and exposure concerns related to contaminated sediments.8 The MGP associatedcontamination is found in several areas, including Chequamegon Bay, Kreher Park and thebase of the bluff. The contaminants of concern found in the coal tar are polycyclic aromatichydrocarbons (PAHs) and volatile organic compounds (VOCs). The health consultationfound that a public health hazard exists when coal tar slicks form on the surface ofChequamegon Bay. The slicks can form when sediments contaminated with coal tar aredisturbed. Such disturbances can occur when boaters drop anchor in contaminated sedimentsor when large waves stir up the lake bed. People at risk for exposure include those whoswim, wade, or play along the lakeshore near Kreher Park when tar slicks are present. Prolonged exposure to coal tar can irritate the skin and eyes and may induce photo-toxicity (acondition where the skin is overly sensitive to sunlight, resulting in an allergic skin reaction) resulting in rapid sunburning.

The recommendations from the October 23 1995, health consultation suggest that people beprevented from coming in contact with tar slicks and to reduce the extent of exposure amongthose who do. Steps include posting warning signs along the contaminated bay section, withinstructions to immediately wash any tar off the skin with soapy water. Otherrecommendations include preventing tar slicks from appearing. Preventative action includesthe establishment of a "no-anchor" zone in the area where sediments are contaminated withcoal tar. Warning buoys are placed outside the perimeter to warn boaters about the hazard. Furthermore, Kreher Park beach, boat ramp pilings, and shoreline surfaces where the publichas access should be inspected for any indications of past tar slicks. The information can beused to identify which areas along the shoreline are most likely to be affected by future tarslicks. Lastly, future remedial activities need to address air management issues. Remediationcan release VOCs into the air, which can induce headaches, dizziness, and nausea in sensitivepeople near the site. So far, there have not been odor or ambient issues or complaints fromprior investigative and interim remedial actions at the Ashland/NSP Lakefront site. Duringthese actions, efforts have been made to ensure that ambient air releases are prevented orminimal. However, it is very important to continue these protective steps during futureremediation to monitor for and prevent excess odors and VOCs from being released andpotentially affecting the health of the public.

  1. Eating Sportfish from Kreher Park

As previously noted, sediments in the contamination zone of Chequamegon Bay containelevated concentrations of PAHs. Nonetheless, people catch and eat fish from Lake Superiornear Kreher Park. The second consultation by the DPH, written October 15 1999, providesconclusions and recommendations which state that PAHs measured in fish from the Ashlandlakefront do not pose a health concern for people who eat fish every day.9 Fish consumptionadvisories for Lake Superior fish do exist for mercury and polychlorinated biphenyls (PCBs)chemicals. The chemicals are probably not related to PAH contaminated Chequamegon Baysediments at Kreher Park. However, PAHs in sediments of Chequamegon at Bay KreherPark remain a public health hazard.

People should continue to follow advice about fish consumption advisories for LakeSuperior, as described in the DNR booklet, Important Health Information for People EatingFish from Wisconsin Waters. Further investigations of Chequamegon Bay sediments atKreher Park should consider testing for mercury and PCBs. Lastly, people should avoidtouching or disturbing tar slicks and contaminated sediments at or near Kreher Park.

  1. Air Management Issues During Remediation

Cleaning up a former MGP site may release odors that can adversely affect human health. The Ashland MGP site is within one-hundred yards of homes and an elementary school. Thus the third consultation, written by DPH in September 2001, addresses the airmanagement issues of MGP remediation.10 The conclusions and recommendations show thatair management and action levels at the Ashland MGP site should focus on the potential thatbenzene vapors are released. As well, preliminary action levels should be set for managingthe release of VOCs and particulates. The breathing zone of worker's involved duringremediation must also be monitored. Air monitoring for human safety must includelower-explosive limit, carbon monoxide, percent oxygen, hydrogen sulfide, and hydrogencyanide levels. Quantitative air sampling should be considered when the worstcontamination is encountered. Remediation contractors should have a planned publicoutreach, including a 24-hour telephone hotline for the public if they have questions.

H. Community and Agency Involvement

The Sigurd Olson Institute and the Ashland-Bayfield County League of Women Voters are theprimary community groups involved with the site. They are holding public education meetings tohelp inform the public about the neighborhood and environmental impacts of the site. Theorganizations are working with local officials, the DNR and Xcel Energy (formally NSP) to keepthe public involved and informed about the investigation and clean-up options for theAshland/NSP Lakefront Site.


Contaminated sediments in Chequamegon Bay remain a human health hazard. Disturbingaffected Chequamegon Bay sediments that are adjacent to Kreher Park can result in the release ofcoal tar slicks. Regular skin contact with PAHs that are typically present in coal tars/NAPLs canincrease a person's lifetime risk for certain skin cancers, but people are unlikely to regularlyallow their skin to become coated with coal tars. However, coal tars/NAPLs are strong skinirritants that can be readily absorbed. A single instance of direct contact with coal tars/NAPLscan cause dermal inflammation and heighten a person's sensitivity to sunburn. A person withcoal tars on their hands can easily rub their eyes, resulting in severe eye irritation.

The Agency on Toxic Substances and Disease Registry (ATSDR) toxicological profile for coaltars states that it "exerts its acute toxic effects in humans primarily via dermal contact, causingstructural damage to the tissues that it comes in contact with, such as the skin and eyes," and that"animal studies corroborate these observations.11" Studies of worker exposures to PAHs haveshown that they "experienced chronic [skin irritation, such as] dermatitis and hyperkeratosis.12"

Also the coal tar toxicological profile reported that "longer periods of dermal exposure to coal tarproducts seem to be associated with dermal irritation and noncancerous lesions, and skin cancerin both humans and animals.13" Evidence shows that mixtures of PAHs are carcinogenic inhumans. The evidence in humans comes primarily from "occupational studies of workersexposed to mixtures containing PAHs as a result of their involvement in such processes as ... coalgasification. Cancer associated with exposure to PAH-containing mixtures in humans occurspredominantly in the lung and skin following inhalation and dermal exposure, respectively.14"

The contaminated portion of Chequamegon Bay, adjacent to Kreher Park, should remain closedto swimming, wading and boating. People should avoid swimming and wading in the restrictedarea. If people get the oily substance on their skin, they should wash their skin right away withsoap and warm water. If their eyes are affected, they should flush their eyes with water. Boatsthat enter the no-anchor zone can also become contaminated with coal tars if an anchor isdropped and disturbs affected sediments. Maintenance should continue of the existing no-swimming warning signs and no-anchor zone buoys. When at Kreher Park, agency staff shouldcontinue to observe the lake and inspect the shoreline for signs of tar slicks. The public shouldbe is encouraged to report tar slicks to staff of the Ashland County Health Department and theDNR Oil slicks may appear after heavy wave action or if a boat enters the exclusion zone anddrops an anchor.

Some people have asked whether the designated swimming beach, east of the boat ramp atKreher Park, is safe. Site-related contamination does not extend to the beach or offshoresediments. The beach is safe for swimming. Moreover, coal tar/NAPL slicks released fromaffected sediments in Kreher Park are not likely to drift away from the contaminated bay area andreach the swimming beach. Oil slick drift would be prevented by the natural geography of thearea, including wave and wind action. If people notice oily substances floating on the water nearthe swimming beach area, it is most likely discharged from boats using the adjacent boat ramp,and not from the contaminated sediments.

While there is significant groundwater contamination at the Ashland Lakefront/NSP site, the Cityof Ashland obtains its municipal drinking water from an intake out in Chequamegon Bay, wellbeyond areas that may be potentially affected. Furthermore, Ashland municipal water isregularly tested for a wide range of contaminants, including a number of chemicals associatedwith MGP-associated wastes. These drinking water tests have not found any such contaminantsin water collected from Lake Superior.

There are two artesian wells in Kreher Park that draw clean groundwater and are safe to drink.People are regularly observed collecting drinking water in containers from these two naturallyflowing wells. The artesian wells, which draw groundwater from the deeper Copper Fallsaquifer, are very close to contaminated areas, yet appear to be beyond the extent of contaminantplumes. Several rounds of water sample tests from the artesian wells have not found anyelevated levels of site-related contamination. It is possible that contaminated groundwater couldeventually spread to these two adjacent artesian wells. For this reason, the artesian well watersshould be regularly tested for VOCs and PAHs.

In 1996, public access to the seep was restricted by installing a six-foot tall chain-linked fencearound the entire seep area. Prior to fencing this seep, it posed a health hazard because peoplecould come in contact with coal tars/NAPL. The fenced area was extended several times in orderto prevent contact with the seep that moved beyond the existing fence. Early in 2001,contaminated soils in this area were excavated and removed. This area was then filled with cleansoils and seeded.

The VOCs in MGP-associated contamination can also be a health concern. The health concernarises when people breathe air that has high levels of VOCs. During cleanup of MGP-associated waste, VOCs can escape as vapors and pose a human health hazard to workers or people nearby. The Ashland MGP site is very close to homes and an elementary school. Environmental actionsat other former manufactured gas plants resulted in airborne releases that were significant andadversely affected human health.15 Coal tar can have an unusually strong moth-ball like smell. Additionally, there are health concerns of VOC compounds which can affect sensitive people,such as children or asthmatics, who may experience difficulty breathing, headaches, dizziness ornausea if exposed to MGP associated vapors for significant lengths of time. Air releases ofVOCs during exploratory site investigations at Ashland, including the excavation of the seep areahave released minimal to zero levels of VOCs. However, during full remediation and clean up ofthe site, airborne releases of VOCs could be significant. Therefore, air management duringcleanup at the Ashland Lakefront site should consider DPH's recommendations in the publichealth consultation of October 15, 2001.16

The VOC vapor intrusion at the upper bluff area into residential homes is also a potential healthconcern. These vapors can escape from highly contaminated groundwater, rise up through soilsand seep into nearby basements. Since very high concentrations of VOCs are present ingroundwater in the vicinity of the former Ashland MGP facility, it is possible that nearby homesmay have VOC vapors coming inside. While such conditions and a vapor migration an intrusionthreat is probably unlikely, testing the indoor air quality of the basement is a prudent measure. Residential homes located adjacent to the contamination area should be sampled during thewinter months to rule out the potential for possible vapor intrusion.

A. Community Health Concerns

1. Public meetings

Since 1995, more than ten public information meetings have occurred regarding the Ashland site. During the meetings held between 1999-2000, four key community issues were identified:

  1. Health concerns - Short and long term effects of exposure to youths and adults, includingwildlife and aquatics; possible affects to drinking water supply; exposure to vapors;potential future problems if nothing is done.

  2. Cleanup/Remediation - Issues raised include the dust, noise, and odors of cleanup; willrecreation be limited, such as access to the marina and boat ramp?; need to maintainaccess to the lakefront while limiting access to the contamination areas; avoid offensivesign language, and work on using a positive message about cleanup.

  3. Cost - What are the costs of cleanup, who will pay?

  4. Overall lake health - How is the community affected by this contamination; what defines a healthy lake?17

During one public meeting during the fall of 2000, community concerns were raised about thesafety of swimming at the Kreher Park beach. The issue was whether or not the beach could get an oil slick by drifting from the contaminated bay area. However, oil slick drift would beprevented by the natural geography of the area, including wave and wind action. If an oil slick does appear near the swimming beach area, it is most likely from boats using the adjacent boatramp, and not from the contaminated sediments.

Additionally at the fall 2000 meeting, a group of participants volunteered for a photo-documentary project, called photo-voice. Participants received cameras and told their story inphotographs regarding their concerns about the Ashland site. The participants felt that becauseAshland is a tourism dependent area, a cleanup should occur, and be done right the first time. Participants also expressed concerns for children because a school and playground are locatedadjacent to the site.

Representatives from DNR and DHFS have also met with residents who live near the site,including visiting with teachers and parents from the school to discuss their health concerns.

2. Other Questions

People have asked other health-related questions about contamination at the Ashland/NSPLakefront Site. The questions and answers are provided below:

  1. What is in a tar or oil slick?
  2. A coal tar slick contains high concentrations of pure coal tar or non-aqueous phase liquid(NAPL). Coal tar is a complex mixture of hundreds to thousands of different chemicals. The chemicals found in coal tar/NAPL are mostly polycyclic aromatic hydrocarbons(PAHs), but also include aromatic volatile organic compounds (VOCs), phenols,heterocyclic oxygen, sulfur, and nitrogen compounds.18 When pure forms ofcontaminants, such as coal tar/NAPL, occur in the environment, they are often referred toas "product." While most of the chemicals in coal tar/NAPL can be harmful at highconcentrations, certain PAHs and VOCs can pose the greatest health risk for people whocome in contact with coal tar/NAPL.

  3. Several employees from the city of Ashland waste water treatment plant have expressedconcerns about exposure to contamination. The employees felt they were potentially exposedto contamination while working at the former waste water treatment plant (WWTP) locatedadjacent to the lakeshore. Thus, were workers of Ashland's WWTP at Kreher Park exposedto coal tar contamination?
  4. DHFS staff have met and talked with workers of the former WWTP. Based on theseconversations it is evident that some workers had direct contact with site-relatedenvironmental contamination at Kreher Park. Some workers reported direct contact withcoal tar/NAPL in trenches when they worked on pipes that carried waste water and otherliquids to the former WWTP. These workers described oily sheens floating ongroundwater that seeped into the trenches. Some workers also reported getting these tarson their skin and several commented on a tar-like odor in the trenches.

    Workers may also have breathed vapors released from coal tar contaminated soils andgroundwater. After the former WWTP stopped receiving waste water, an employee whoassisted with the decommission of the facility smelled coal tar-like odors. The tar smellsindicate that vapors from contaminated soils and groundwater had filtered into the formerWWTP building. It is possible that coal tar odors were previously masked by strongerodors of sewage waste water. It is difficult to determine when the vapors entered thebuildings. DNR staff who inspected the building also reported strong coal tar odors. Theyalso observed evidence of contaminated water during a past visit to the building.However, the presence of coal tar odors inside the building may not indicate thatbreathing the air is unsafe. Some chemicals in coal tar/NAPL, such as naphthalene, havean extremely low odor threshold, and people can notice naphthalene odors in air at levelsthat are not a health concern. However, some of the other chemicals in MGP wastes,such as benzene, can pose a health risk at very low levels.

    Health officials do not know the type or amount of site-related contaminants that workersonce breathed at the former WWTP. Conducting an indoor air test may provide clues tothe type and amount of chemicals present. However, testing is difficult for a number ofreasons. DHFS believes it would be difficult to reconstruct the indoor air conditions of afacility that has been closed for ten years. Additionally, when the WWTP was inoperation, a complex mixture of chemicals from processed sewage probably had a majorimpact on the indoor air conditions at the facility.

  5. What are the health concerns for former WWTP workers?
  6. Some former WWTP workers appear to have come in contact with MGP-relatedcontamination. These exposures were probably greatest when workers were in trenches,handling pipes that carried waste water and other liquids to the former WWTP. Theworkers described seeing oily sheens floating on groundwater that seeped into thetrenches. Some workers also reported getting tars on their skin and several commentedabout tar-like odors.

    As previously mentioned, the chemicals in coal tars/NAPLs are strong skin irritants; andmay cause a rash on sensitive people. It is also known that people who get coaltars/NAPL on their skin can have an increased sensitivity to becoming sunburned. Regular skin exposure to the PAHs in coal tar can increase the risk of developing certainnon-melanoma skin cancers.

    One individual who worked at the former WWTP expressed concern that his skinexposure to coal tars/NAPLs caused non-melanoma skin cancer. Regular skin contactwith coal tar/NAPL can increase a person's risk of developing skin cancer, but it isdifficult to conclude that regular exposure actually caused this case of cancer. Non-melanoma skin cancers (squamous cell carcinoma and basal cell carcinoma) are the mostcommon forms of cancer throughout the United States, with an estimated 9,800 cases inWisconsin each year. The most common risk factors for developing skin cancer are: 1)increased exposure to the sun, and 2) genetic disposition.

B. Child Health Issues

Due to the proximity of an elementary school to the Ashland MGP site, including Kreher Park atthe lakefront, child health concerns must be considered. The media of concern is the offshoresediments and air emissions during remediation. Soil and groundwater contamination do notpose an immediate health threat to children. The recommendations for preventing contact withoffshore sediments and oil slicks should actively remain. Children and adults who eat fish fromChequamegon Bay should follow the DNR booklet Important Health Information for PeopleEating Fish from Wisconsin Waters for Lake Superior fish. During remediation activities, airemissions must be strictly controlled since children are a sub-population sensitive to irritation from MGP air emissions.


  1. Contaminatedsediments in Chequamegon Bay at the Ashland Lakefront/NSP site remain ahuman health hazard, due to contact of oil slicks. Human contact with oil slicks may causeskin irritation. Eye irritation may also occur if the oil is accidentally rubbed into the eyes. Skin contact may also cause photosensitivity, which could result in an increased risk ofsunburn. However, the beach at Kreher Park is safe for swimming.

  2. Other health concerns surround the potential use of groundwater. Although the city ofAshland does not use the groundwater from the contamination zone (the Ashland municipalwater supply is drawn from much farther out in Chequamegon Bay), a number of peopledrink water from two artesian wells adjacent to the contamination zone. One well is locatednext to the marina; the other is in Kreher Park. The artesian water comes from deep in the ground, but should be regularly tested for VOCs and PAHs.

  3. Recent fish sampling from Chequamegon Bay indicates that fish do not contain levels of site-related chemicals that are a health concern. However, people should continue to follow fishconsumption advice for Lake Superior. Recommendations are found in the WisconsinDepartment of Natural Resources (DNR) booklet Important Health Information for PeopleEating Fish from Wisconsin Waters which is available from the Ashland County HealthDepartment, or the Internet at:

  4. During the cleanup of MGP associated waste, VOCs can escape as vapors and pose a humanhealth hazard to workers or people nearby. When sensitive people breathe coal tar wastechemicals they may experience health effects.

  5. MGP-related vapors that move through soils at the upper bluff area may enter homes and be a health concern. While the chance of this occurrence is not likely, DHFS regards indoor air sampling as a precautionary measure.


  1. The contaminated portion of Chequamegon Bay at the Ashland Lakefront/NSP site shouldremain closed to swimming, wading and boating. Warning signs and buoys should remainposted. The area should continue to remain off limits to boating and swimming. People who get the coal tar/NAPL on their skin should wash their skin right away with soap and warm water. If their eyes are affected, they should flush their eyes with water. Additionally, the contaminated portion of Chequamegon Bay should be monitored for oil slicks.

  2. If coal tar/NAPL gets on skin, it should be washed immediately with plenty of warm, soapy water and people should avoid exposure of affected skin to sunlight.

  3. The two artesian drinking water wells at Kreher Park should be regularly tested for site-related contaminants.

  4. People who eat Lake Superior fish should follow the DNR fish consumption advisory forother contaminants, such as mercury.

  5. Since homes and a school are very close to the Ashland Lakefront/NSP site, the stringent management of VOC air emissions is crucial during remediation activities. Air management during cleanup needs to consider recommendations in the public health consultation of October 15, 2001.

  6. The indoor air sampling of homes adjacent to the contamination area should be considered possible VOC air intrusion.


  1. DPH will continue to work with the Wisconsin DNR remediation and redevelopment team toensure that the site recommendations are implemented for the Ashland site.

  2. DPH will work with the development of air monitoring and air quality control plans to ensure that public health is protected during remediation.

  3. DPH will continue to conduct public health outreach of community stakeholders, involving them in the decision making, and informing them of health risks posed during cleanup of the Ashland site.

  4. DPH will coordinate public health outreach and community involvement activities with the Ashland County Health Department, local citizen groups, and other involved parties.


1. - Wisconsin Department of Natural Resources. Draft Community Involvement Plan, Ashland/NSP Lakefront Site, Ashland, Wisconsin (April 2001).

2. - Ibid.

3. - The Source Book of ZIP Code Demographics (Census Edition, Vol. 1). CACI Marketing Systems, 1991.

4. - U.S. EPA. HRS Documentation Record for Ashland/Northern States Power Lakefront. EPA ID No. WISFN0507952. NPL-U34-2-4-R5. October 30, 2000.

5. - Wisconsin Department of Natural Resources. Draft Community Involvement Plan, Ashland/NSP Lakefront Site, Ashland, Wisconsin (April 2001).

6. - Wisconsin Department of Natural Resources. Fact Sheet, A History of the Ashland/Northern States Power Lakefront Site, RR-645 (June 2001).

7. - Short Elliott Hendrickson, Inc. (SEH). Comprehensive Environmental Investigation Report (May 1997). SEH No. WIDNR9401.00

8. - Wisconsin Division of Public Health. Health Consultation on Exposure to Coal Tar Associated with the Manufactured Gas Plant Site in the City of Ashland (October 23, 1995).

9. - Wisconsin Division of Public Health. Health Consultation on Fish Tissue Exposure Investigation of Contaminated Chequamegon Bay Sediments at Kreher Park, Ashland, Ashland County, Wisconsin (October 25, 1999).

10. - Wisconsin Division of Public Health. Draft Health Consultation on Air Effects and Human Health Concerns Associated with the Remediation of Former Manufactured Gas Plant Sites (September 2001).

11. - Agency for Toxic Substances and Disease Registry. Toxicological Profile for Wood Creosote, Coal Tar Creosote, Coal Tar, Coal Tar Pitch, and Coal Tar Pitch Volatiles. Update - Public Comment Draft. Atlanta, GA: ATSDR. September 2000.

12. - Agency for Toxic Substances and Disease Registry. Toxicological Profile for Polycyclic Aromatic Hydrocarbons. (Update). Atlanta, GA: ATSDR. August 1995.

13. - Ibid..

14.- Ibid.

15.- Wisconsin DPH. Draft Health Consultation on Air Effects, 2001.

16. - Ibid.

17. - Wisconsin DNR. Draft Community Involvement Plan, 2001.

18. - Agency for Toxic Substances and Disease Registry. Toxicological Profile for Polycyclic Aromatic Hydrocarbons. (Update). Atlanta, GA: ATSDR. August 1995.


Henry Nehls-Lowe, MPH - Epidemiologist
Eric Aakko, MS, CHES - Health Educator
Bureau of Environmental Health
Division of Public Health
Wisconsin Department of Health & Family Services


This Coal Tar Contamination Associated with a Former Manufactured Gas Plant Ashland/Northern States Power Lakefront Public Health Assessment was prepared by the Wisconsin Department of Health and Social 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 assessment was begun.

Gail D. Godfrey
Technical Project Officer, SPS, SSAB, DHAC

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

Sven E. Rodenback
for Roberta Erlwein
Chief, State Program Section, DHAC, ATSDR


Table 1.

Soil Sample Results1 Ashland, Wisconsin
Table 1a - Volatile Organic Compound (VOC) Concentrations
Analyte WDNR
Lakefront Upper Bluff Area
Frequency of Detection Range Frequency of Detection

Benzene 0.0055 13/28 645 0.005 6/8 19.8 0.016
Toluene 1.5 4/28 2,007 0.027 6/8 43.2 0.004
Ethylbenzene 2.9 11/28 2,973 0.147 4/8 75.8 0.014
Xylenes (total) 4.1 11/28 4,981 0.232 4/8 94.1 0.046
Naphthalene n/a 25/28 28,469 0.008 3/8 863 0.016
1 - SEH No. WIDNR9401.00 (May, 1997)
2 - WDNR SoilResidual Contaminant Level (RCL )
Note: All concentrations are expressed in parts per million (ppm)

(PAH) Concentrations
Analyte Lakefront Upper Bluff Area
Frequency of Detection Range Frequency of Detection Range
Benzo(a)anthracene 20/28 323 0.203 5/8 106 2.1
Benzo(a)pyrene 20/28 206 0.172 6/8 111 0.13
Benzo(b)fluoranthene 20/28 191 0.247 5/8 89.6 2.8
Benzo(k)fluoranthene 15/28 74 0.188 5/8 42.8 0.28
Indeno(1,2,3-cd)pyrene 14/28 65.6 1.05 4/8 56 1.1
Chrysene 21/28 313 0.449 5/8 101 2.3
Dibenzo(a,h)anthracene 3/28 10.8 0.513 2/8 10.6 4.27
1 - SEH No. WIDNR9401.00 (May, 1997)
Note: All concentrations are expressed in parts per million (ppm)

Table 2.

Offshore Soil and Sediment Sample Results1Ashland, Wisconsin
Table 2a - Volatile Organic Compound (VOC) Concentrations
Analyte Frequency of Detection Range
Benzene 22/107 55,000 57
Toluene 36/107 220,000 54
Ethylbenzene 38/107 510,000 35
Xylenes (total) 37/107 590,000 43
Naphthalene 42/107 160,000 43,000
1 - SEH No. WIDNR9401.00 (May, 1997)
Note: All concentrations are expressed in parts per million (ppm)

Table 2b.

Polycyclic Aromatic Hydrocarbon (PAH) Concentrations
Analyte Frequency of Detection Range
Benzo(a)anthracene 22/106 67 0.42
Benzo(a)pyrene 17/106 49 0.33
Benzo(b)fluoranthene 13/106 36 0.36
Indeno(1,2,3-cd)pyrene 3/106 8.77 0.82
Chrysene 22/106 36 0.41
1 - SEH No. WIDNR9401.00 (May, 1997)
Note: All concentrations are expressed in parts per million (ppm)

Table 3.

Groundwater Sample Results1 Volatile Organic Compound Concentrations Ashland, Wisconsin
Volatile Organic Compound (VOC) Concentrations
Analyte WDNR Groundwater Enforcement Standard (ES) Lakefront Upper Bluff Area Seep Area
Frequency of Detection Range Frequency of Detection Range Range
Benzene 5 41/54 4,100 0.08 26/28 79,000 0.03 3,500 3,250
Toluene 343 7/48 651 29 24/26 36,000 0.45 650 650
Ethylbenzene 700 29/48 2,300 5 16/23 3,180 0.36 670 378
Xylenes (total) 620 21/48 2,430 52 22/24 11,500 0.61 483 390
Naphthalene 40 40/49 18,600 1.15 25/28 21,000 0.86 6,700 1,300
1 - SEH No. WIDNR9401.00 (May, 1997)
Note: All concentrations are expressed in parts per billion (ppb)

Table 4.

Groundwater Sample Results1 Polycyclic Aromatic Hydrocarbon Concentrations Ashland, Wisconsin
Polycyclic Aromatic Hydrocarbon (PAH) Concentrations
Analyte Lakefront Upper Bluff Area Seep Area
Frequency of Detection Range Frequency of Detection Range Range
Benzo(a)anthracene 33/46 3,465 0.522 8/23 921 3.1 6,800 4,800
Benzo(a)pyrene* 33/46 3,278 0.539 7/23 898 3.4 7,754 5,866
Benzo(b)fluoranthene 32/43 2.136 2.69 8/23 715 3.7 6,260 4,300
Benzo(k)fluoranthene 24/43 1,272 1.53 2/6 339 5.2 3,066 1,300
Indeno(1,2,3-cd)pyrene 27/43 1,044 2.75 2/7 362 4.1 3,578 1,600
Chrysene 29/43 2,597 1.75 8/23 843 3 7,298 4,600
Dibenzo(a,h)anthracene 3/43 26 1.45 n/a n/a n/a 624 624
1 - SEH No. WIDNR9401.00 (May, 1997)
* - WDNR GroundwaterEnforcement Standard (ES) - 0.2 ppb; no ES for other chemicals in this table
Note: All concentrations are expressed in parts per billion (ppb)


The response to each comment is followed by a bulleted and italicized notation.

  1. "Throughout the Public Health Assessment, the Department assigns responsibility for allimpacts at the site to the former manufactured gas plant ("MGP"). The Assessment identifies-- from the document title forward -- the MGP as the sole source of coal tar/creosotecontamination at the site. A review of the public record for this site, as well as conclusionsoffered by WDNR's consultant Short, Elliott and Hendrickson, reveal that multiple sourcesof contaminants exist in the Ashland Lakefront Project area and that other sources, such asthe existence of historic waste disposal practices at Kreher Park and wood treatment practicesutilizing tar and/or creosote products conducted by the John Schroeder Lumber Company,caused or contributed to a portion of the impacts in the environment. The Assessment is atminimum incomplete and nearly misleading when it fails to apprise the public of all of thesources contributing to the problem."
  2. "We [Xcel Energy] requests that the Department revise ... either remove the specificreference to the MGP as the sole cause of contaminants or add references to wastes resultingfrom the former wood treatment operation and waste disposal practices at the Lakefront."

  • In response and to address this comment, the following text was added on page 4 of this public health assessment:
  • "The major contaminant components found at the Ashland/Northern States PowerLakefront site are typical of other former manufactured gas plants in Wisconsinand the country. However, this contamination has also been found at other, non-MGP sites where there were different types of industrial processes, such as awood treatment operations or petroleum facilities. Xcel Energy currentlycontends that contamination currently found below the bluff (beneath KreherPark and lake sediments) is not solely from the former MGP site, but currentlyDNR reports they do not necessarily agree. Also, DHFS defers to DNR andU.S. EPA on this issue. However, to address this overall concept, the generaldescription of contaminants in this public health assessment are referred to as"MGP-related" or "MGP-associated" contaminants."

  1. "Given the foregoing, it would be more appropriate to retitle the Public Health Assessment to read 'Contamination Associated with Historic Lakefront Activities'."
  • The Agency for Toxic Substances and Disease Registry requires that the title of this public health assessment include the official name of the site, which is the"Ashland/Northern States Power Lakefront."
  1. "In the Summary section on page 1, the first bullet, the sentence '[c]ontaminated sediments inChequamegon Bay are a human health hazard' is misleading. The contaminated sedimentsare a human health hazard only to the extent that (i) the sediments are exposed, or (ii)contaminants affect the food chain to the extent of human uptake. The Department hasdetermined that the latter exposure risk is not present. With respect to the exposure risk, thesediments are currently entombed and a navigation safety zone designation is in place. So,only to the extent the sediments are disturbed or directly contacted are they a human health risk."
  • DHFS does not concur that contaminants in sediments, in high concentrations or product, atKreher Park are "entombed", which implies that they are unlikely to be easily disturbed bynatural and human factors. Sufficient site-specific information indicates that contaminatedsediments at Kreher Park are be exposed and released to the environment. These releasesappear to occur as a result of natural forces, such as wave action, as well as man-madephysical action. Furthermore, despite warning signs and navigational warning buoys,agencies continue to receive reports of park users and boaters who fail to notice thesewarning markers and then enter the area with affected sediments. These individuals are thenlikely to come in contact with contaminants released from affected sediments, particularly ifsediments are physically disturbed by wading or the dropping of anchors. Until a morerestrictive physical barrier is installed that prevents people from entering this area andhaving direct contact with contaminants, DHFS views that this area is a human healthhazard.
  1. "In the Summary section on page 1, the last bullet, the Department recommends that thehomes close to the site be tested for the presence of vapors entering basements. Howeverconclusion #5 on page 13 states that the chance of vapors entering the homes and becoming ahealth concern is unlikely. This appears to be an inconsistency, unless the Department issuggesting that sampling be performed to confirm the lack of vapor reception. We [XcelEnergy] ask that this recommendation be more fully explained and put into better context so as to not unnecessarily alarm residents."
  • As mentioned in the text on page 12, the threat of vapor intrusion to the indoor air of nearbyhomes is a low possibility. However, given close proximity of homes to high levels ofsubsurface contamination, DHFS regards indoor air sampling as a precautionary andreasonable measure to rule out the potential for vapor migration and intrusion to the indoor inhalation pathway of nearby homes.
  1. "The sentence in the Introduction on page 2 stating that new sampling data of soil,groundwater and offshore sediments were reviewed in preparation of the Public HealthAssessment appears incorrect. In preparation of the Public Health Assessment theDepartment appears to not have considered any of the data generated by environmentalinvestigations conducted since the 1997 SEH report. For example, the Department states thatadditional environmental reports since the 1997 SEH Report "were not available" at the timeof preparing the Public Health Assessment (page 5). The official Administrative Record,maintained by WDNR, contains complete copies of all environmental reports generatedsubsequent to the 1997 SEH Report and prior to the Public Health Assessment."
  • This is noted and a rewriting of the sentence was done within the document. The PHA reporthas been modified to acknowledge that additional environmental investigations have beenconducted at the Ashland/NSP lakefront site since the 1997 SEH report. However thesesubsequent reports have not resulted in significant changes to the original conclusions of the initial public health consultation released in 1995 by DHFS.
  1. "In the box on page 4, the Department refers to studies conducted from 1995-2001, includingan ecological risk assessment, that perpetually conclude that ' . . . the site poses significantrisks to human health and environment.' The Ecological Risk Assessment ('ERA')conducted by WDNR's consultant is not yet final and prior versions have come under heavycriticism by both NSP and USEPA. The study was fatally flawed and it is not possible todraw the conclusion the Department makes from this study in its current form. The lesscontroversial human health risk assessment concluded the site posed risks under a verylimited set of circumstances, such as utility worker exposure and the like. We [Xcel Energy] believe the Department's language is an oversimplification of a complex site."
  • The text box on page 4 was modified to incorporate Exel Energy's disagreement with DNR'sfindings of the ERA. However, it should be noted that this modification to the PHA reportshould not be interpreted that DHFS endorses Xcel Energy's opinion on this specific issue. DHFS defers to DNR and U.S. EPA regarding such matters.
  1. "On November 20, 1997 both the City of Ashland and Wisconsin Central Limited Railroadwere notified by WDNR as a Potentially Responsible Parties for the contamination at theLakefront. This is a factual reference that should be added to paragraph 2 on page 5 forcompleteness."
  • As requested, the document was modified.
  1. "The sentence, 'This free product or NAPL consists of oil, tar and other wastes characteristicof former manufactured gas plants' in the Groundwater section of page 6, may be correct, butit is incomplete. As noted above, the makeup of the NAPL waste is also consistent with orcharacteristic of wood treatment residues. In fact, ratios of certain chemical compounds havebeen documented in samples retrieved from the site in proportions consistent withU.S. EPA's reference for classic wood treatment compounds. See 'Comparative Analysis of Sediment Samples from the Chequamegon Bay Near the Kreher Park Shoreline, AshlandWisconsin' prepared by the Gas Technology Institute, March 2000."
  • Refer to the response to public comment No. 1
  1. "In Section II G - Summary of Public Health Consultations, the sentence '[l]astly, futureremedial activities need to address air management issues' suggests that past remedialactivities have not addressed these issues. Indeed, past response and investigation activitiesat the site have consider air management issues. Examples of this include, air monitoringperformed coincident with the operation of the interim tar recovery system operating on the NSP site to ensure compliance with administrative codes concerning air emissions andpermitting, as well as the recent property boundary ambient air monitoring assessmentperformed during investigatory trenching activities conducted last fall at the site."
  • Appropriate modifications were added to this section.
  1. "In Section III, Paragraphs 3 on page 9, the Department recommends that '...the contaminatedportion of Chequamegon Bay should be monitored for tar slicks'. We [Xcel Energy] do notunderstand toward what end the monitoring of tar slicks on Chequamegon Bay isrecommended. The Department has clarified that the navigation safety zone should bemaintained while remedial action options are under consideration and implementation. It isunclear to us what benefit can be derived from focusing resources on an effort to monitorChequamegon Bay for the presence of tar slicks. To the extent that such slicks result fromthe natural disturbance of sediments via wave action or otherwise (and not from a humanviolation of the navigation safety zone), we do not understand what further can be done with respect to the concern for tar slicks until the remedy is implemented at the site."
  • Continued attention to the occurrence of tar slicks is important in determining whether thereare changing conditions that are affecting contaminated sediments at Kreher Park. Forexample, reports of an increase in the apparent frequency or size of tar slick would triggeran evaluation of whether the existing site-restrictions should be adjusted. In response to this issue and the above comment, text was modified on page 10.
  1. "In the first full paragraph on page 10, the last four sentences should be stricken. The seep area was not remediated in 2001, and the fence remains in place."
  • Sentence removal is noted and changes, as appropriate, were made.

1. The major contaminant components found at the Ashland/Northern States Power Lakefront site are typical of other former manufactured gas plants in Wisconsin and the country. However, this contamination has also been found at other, non-MGP sites where there were different types of industrial processes, such as a wood treatment operations or petroleum facilities. Xcel Energy currently contends that contamination currently found below the bluff (beneath Kreher Park and lake sediments) is not solely from the former MGP site, but currently DNR reports they do not necessarily agree. Also, DHFS defers to DNR and U.S. EPA on this issue. However, to address this overall concept, the general description of contaminants in this public health assessment report are referred to as "MGP-related" or "MGP-associated" contaminants or waste.

Table of Contents The U.S. Government's Official Web PortalDepartment of Health and Human Services
Agency for Toxic Substances and Disease Registry, 4770 Buford Hwy NE, Atlanta, GA 30341
Contact CDC: 800-232-4636 / TTY: 888-232-6348

A-Z Index

  1. A
  2. B
  3. C
  4. D
  5. E
  6. F
  7. G
  8. H
  9. I
  10. J
  11. K
  12. L
  13. M
  14. N
  15. O
  16. P
  17. Q
  18. R
  19. S
  20. T
  21. U
  22. V
  23. W
  24. X
  25. Y
  26. Z
  27. #