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The Koppers Wood Treating Company (Koppers) is an abandoned wood treating facility north ofCarbondale, Illinois, that ceased operations in July 1991. A maintenance worker periodicallyvisits the site to service the on-site wastewater treatment plant but does not remain at the site fulltime. A fence surrounds the site, and all access roads into the site are secured by locked gates.

Soils at the site are visibly contaminated with creosote. Groundwater contamination at the siteincludes phenols, metals, volatile organic chemicals, pentachlorophenol (PCP), and polycyclicaromatic hydrocarbons (PAHs). Limited removal activities took place at the site in 1991, butmuch of the contamination remains. Past accidental releases of creosote products have resulted inoff-site contamination of Crab Orchard Creek sediment.

A public water supply system services most of the homes near the site. Four private residentialwells about 0.5 miles north of the site were sampled for site-related contaminants includingphenols, PCP, and PAHs. Samples collected in 1989 contained low levels of PAHs in two of theresidential wells. In 1992, the Lakeside Water District distribution system was extended toprovide water to homes north of Carbondale, including the four homes where private wells were sampled.

Completed exposure pathways include:

  • past ingestion, inhalation, and dermal contact of contaminated groundwater by private well users;
  • past inhalation of airborne emissions from plant operations; and
  • past dermal contact, inhalation, and ingestion of contaminated soils, and fugitive dust by on-site workers.

Areas of extensive soil and groundwater contamination remain at the site, but access to the site isrestricted by a fence and locked gates. From the information reviewed, IDPH concludes thatcurrent conditions at the former Koppers wood-treating facility do not threaten the health of nearby residents.


The Illinois Environmental Protection Agency (IEPA) requested that the Illinois Department ofPublic Health (IDPH) conduct a public health assessment for the Koppers Wood TreatingCompany (Koppers) site. The purpose of this public health assessment is to evaluate, based onthe information currently available, any known or potential adverse human health hazards related to the site.


Site Location

The Koppers site occupies about 136 acres along North Marion Street on the northeastern edge ofCarbondale in Jackson County (Figure 1). Land surrounding the Koppers site is used forresidential, agricultural, commercial and industrial purposes. An abandoned railroad trackborders the southern edge of the site. The nearest homes are immediately south of the track at thewestern end of the facility. A combination of cultivated, undeveloped, and wooded land is northand east of the site. Only a few rural residential dwellings are scattered throughout the immediatearea. An Illinois Central Railroad yard is on land west of the Koppers facility.

Site History

The Koppers site was a wood treating facility that began operation in 1905 (Figure 2). It wasformerly one of the world's largest creosote treatment plants. The site remained active until July1991. A similar Koppers facility near Galesburg, Illinois, is listed on the federal National Priorities List (NPL).

Three off-site environmental incidents have been reported in the history of the facility.

  • In 1939, creosote was reportedly diverted into a wastewater lagoon at the eastern portion of the site by a northern drainage ditch to prevent a fire. Heavy rains then caused a breach of the lagoon berm spilling wastewater, creosote, and sludge into an off-site spill area and Glade Creek (Figure 1).
  • In the summer of 1962, a fish kill occurred in the Big Muddy River due to phenolpoisoning. The cause of this incident was traced to an apparent overflow of a lagoon atthe Koppers site. Koppers and the Illinois Department of Conservation agreed to an out-of-court settlement for restocking the river [1].
  • In 1981, two cows grazing on land next to the Koppers wood treating site died. Anautopsy on one of the two deceased cows revealed the cow had ingested creosote-containing material. This incident led to IEPA conducting a preliminary remedial investigation at the Koppers site [2].

The variety of wood treating products used during facility operation included:

  • Grade 1 Creosote - undiluted creosote;
  • 60-40 Creosote - 60% creosote and 40% coal tar;
  • Pentachlorophenol (PCP) - 7.5% pentachlorophenol in fuel oil;
  • Fluoro-chrome-arsenate-phenol (FCAP) - mixture of sodium fluoride, sodium arsenate,sodium chromate and dinitrophenol;
  • Chromated zinc chloride (CZC) - mixture of zinc chloride and sodium chromate; and
  • Non-combustible fire retardant (Non-Com) - mixture of ammonium sulfate, ammoniumphosphate, boric acid, borax and dicyandiamide [3].

Information recording periods of use of these chemicals is not complete. The most recent woodtreatment process used only 60-40 creosote. The wood was treated in pressure-vacuum cylinderspowered by steam produced by a wood-fired boiler. After treatment, the preserved wood wasmoved onto drip tracks to air dry [4]. A drain system was in place to collect runoff from the driptrack area. Besides the runoff waste, production wastes were also generated. Koppers treated therunoff and production wastes at the facility in an oil-water separator for reclamation of the oil.

In June 1986, Koppers entered into an Administrative Order of Consent (AOC) with the U.S.Environmental Protection Agency (USEPA) and IEPA to perform corrective actions and otherresponse measures at the site.

Before 1988, the Koppers facility treated wastewater by collecting the effluent from the oil-waterseparators in a wastewater lagoon/spray irrigation field system. In November 1988, the city ofCarbondale began accepting wastewater from Koppers. When Koppers abandoned the lagoonsystem, they generated more wastewater than they could transport and store, so they evaporatedwastewater into the atmosphere by heating it in open-topped tanks. When Koppers wasevaporating the water, the surrounding community complained about a strong, creosote-like odororiginating from the facility.

In July 1991, Koppers ceased operations at their Carbondale facility; the company dismantledand removed most of the equipment and buildings. Storage tanks, the office building, and thewastewater treatment plant are all that remain at the site. Limited soil excavation around thework tanks and treatment cylinders was conducted at the time of dismantling; however, most ofthe visibly-contaminated soil remains on the site.

To control the shallow contaminated groundwater discharging into Glade Creek, Koppersinstalled a grout blanket in the bed of the creek. The grout blanket is about 700 feet long and 30feet wide, extending from bank to bank. The grout blanket collects and conveys the groundwaterthat is visibly contaminated with creosote to a collection manhole where the material isperiodically collected. The collected material is then treated on the site in the activated sludge-wastewater treatment plant.


Carbondale is in the southeastern portion of Jackson County, Illinois. The 1990 U.S. Censusreported the population of Carbondale at approximately 32,000 people. This number includesSouthern Illinois University (SIU) students who reside within the city limits. The SIU campus isin the southern portion of Carbondale, 2 miles southwest of the Koppers site. The enrollment atSIU is approximately 24,000. The population within a 4-mile radius of the site is approximately38,000 people.

The nearest populated area is a residential neighborhood immediately south of the western end ofthe facility. This lower-income neighborhood has a population of about 1,600 persons and iscomprised predominately of African Americans. According to the 1990 U.S. Census, the averageage of this population is 28 years. A few scattered homes are in the rural area immediately northof the site. Most of those dwellings are along Reed Station Road.

Natural Resource Use

Cedar Lake, which is about 8 miles south of the Koppers site, supplies the drinking water forCarbondale and the surrounding area. Surface water leaving the site has no connection to CedarLake [5]. Most of the dwellings in the rural area north and northeast of Koppers are connected tothe Lakeside Water District, which also receives water from the Cedar Lake supply system. Priorto 1992, about 40 homes in that area had private wells [6]. Four private wells were within onemile north of the site. Three of the wells were at homes, and the fourth well, at a barn, is used forwatering livestock.In September 1992, public water was provided to the area.

Glade Creek flows through the western portion of the site, around the northern edge, and thenpast the eastern end of the site [2]. Glade Creek merges with Piles Fork Creek and then flowsinto Crab Orchard Creek about 1 mile downstream of the site. Surface water draining from thesite flows into Glade Creek and Piles Fork Creek. Site-impacted shallow groundwater alsodischarges into Glade Creek. Both Glade Creek and Piles Fork Creek typically have low flowrates and become intermittent during dry periods, which makes them generally unattractive forrecreational use such as swimming or fishing. Neither of the creeks is used as drinking watersources; however, in some areas, the water is available to livestock. Piles Fork Creek is used asthe receiving stream for treated waste from the Carbondale sewage treatment plant. Crab OrchardCreek is also not a drinking water source for humans, but it may be used for recreationalpurposes such as wading, swimming and sport fishing. Crab Orchard Creek ultimately flows intothe Big Muddy River.

Before 1993, the community of Royalton used the Big Muddy River as its drinking water supply,but the Royalton water treatment plant was about 9 miles upstream of the Crab Orchard Creekconfluence. In 1993, Royalton connected to the Rend Lake Water District. The Big Muddy Riveris not used as a public water supply downstream of this confluence. Recreational use of the BigMuddy River includes boating, swimming, and sport and commercial fishing [7].

Site Visit

IDPH staff visited the site in January 2000. No site personnel were available at that time. The sitewas vacant and secured by a locked gate. As seen from the fence line, the only structuresremaining on the site were four tanks, the former office building, a bathhouse, and the activated sludge-wastewater treatment plant.


Chemicals of Interest

IDPH compared the maximum level of each contaminant detected during environmentalsampling with appropriate screening comparison values, when available, to select contaminantsfor further evaluation for both carcinogenic and non-carcinogenic health effects. A detaileddiscussion of each of the comparison values used is found in Attachment 1.

The comparison values are used only to screen for contaminants that should be evaluated furtherand do not represent thresholds of toxicity. Though some of these chemicals may exist at levelsgreater than comparison values, they can only affect someone who comes in contact with thecontaminants and receives a high enough dose for adverse effects to occur. The amount of thecontaminant, the duration and route of exposure, and the health status of exposed individuals areimportant factors in determining the potential for adverse health effects.

The chemicals of interest at this site are phenols, pentachlorophenol (PCP), metals, volatileorganic compounds (VOCs), and semi-volatile organic compounds (SVOCs), includingpolycyclic aromatic hydrocarbons (PAHs). The following discussion explains the contamination found in each environmental medium sampled.


An extensive network of 90 monitoring wells is on the site. Results of sampling of those wellsshows that on-site groundwater is contaminated with phenols, PCP, metals, PAHs, and VOCs.Groundwater quality is affected beneath the site to the bedrock layer. The extent of thecontamination reveals both a vertical and horizontal contaminant migration. The most elevatedlevels of contamination are PAHs in the shallow monitoring wells [8]. Table 1 shows thecontaminants of interest and their concentration range detected in on-site groundwater.

No site related contaminants have been detected off the site. Four residential wells north ofKoppers were sampled in 1989. These residences now have a public water supply. Sampling ofthe perimeter monitoring wells shows that groundwater contamination remains confined to the site.


The soil investigation at the site consisted of subsurface samples collected from areas of bothobvious contamination and from areas not affected by previous site activities. The most recentsoil sampling activities were completed in 1996.

The areas of known contamination from site activities consisted of eight locations: (1) thetreatment cylinder area; (2) the former spray irrigation field; (3) the drip track area; (4) the northditch area; (5) the storage tank area; (6) the service yard; (7) the off-site spill area; and (8) theformer lagoon area. Soil borings from those areas were collected from extended depths until twosamples showed no visible creosote; however, borings were not extended any deeper than 30 feetbelow the water table.

Soil contamination at the site included PCP, oil and grease, phenols, metals, and PAHs. Samplescontaining elevated levels of PCP were collected from borings exhibiting a diesel fuel odor(Table 2) [8]. A sample collected from the service yard area showed pure creosote at a depth of16.5 feet. In the storage tank and the north ditch areas, visual contamination was recorded at adepth of 40.5 feet.

Five surface soil samples (0-6 inches) were collected in February 1990 from a livestock pasturearea near the "off-site spill" area in the Glade Creek flood plain. Three background surfacesamples were also collected. Only one background sample was off the site south of thesoutheastern site boundary along the railroad right-of-way. The other two background sampleswere within site boundaries, one along the northeastern boundary in the Glade Creek flood plainand the other along the northern boundary east of Smith Ditch.

The surface soil samples were analyzed only for PAHs, PCP, and metals. Laboratory results ofthe surface soil samples reported the presence of low levels of PAHs. PCP was not detected inany of the "background" samples but was detected in one of the five surface soil samples collected in the Glade Creek flood plain.


Air sampling was conducted at the site in October 1987; however, the plant was not operatingduring the air sampling activities. Air samples were collected and measured for both VOCs andSVOCs.

Three locations were chosen for ambient air monitoring, one at the center of the plant area,another at an area downwind of the site, and the other at a site determined to be upwind of thesite at the time the samples were collected. Five above ground sampling stations for SVOCs wereselected based on soil and groundwater sampling results. Soil gas sampling for VOCs wasconducted below the surface at three locations near the SVOC sampling stations.

No VOCs were detected in the soil gas samples. Naphthalene was detected at a maximum levelof 18.34 milligrams per cubic meter (mg/m3) below ground near the waste pile. Above groundsamples in the plant area contained only PAHs; however, upwind samples also contained PAHs.Since groundwater contamination is confined to the site, exposure to soil gas is not expected in nearby homes.

Surface Water

Surface water sampling of the streams was conducted during periods of both low and high flow.Table 3 shows the maximum level of site-related contaminants detected in the surface watersamples.

Low levels of PAHs were detected in surface water. Most detections were in samples near the1939 off-site spill area when Glade Creek was at a low flow level. Sampling during higher flowshowed low levels of PAHs farther downstream than were found during the low flow sampling.Only one sample had a detectable level of PCP. Phenol was not detected in any surface watersamples. Low levels of VOCs, including benzene, were detected, while no metals were identified at elevated levels.


Visual signs of creosote contamination such as oil globules and an oily sheen were observed insediments from Glade Creek and Crab Orchard Creek. The length of the ditch along the southernend of the Koppers facility also contained visual creosote in the sediment [5]. Elevated levels ofPAHs were detected in the sediment, which confirmed the visual observations (Table 3). Thehighest level of PAHs was detected in the ditch along the southern end of the facility. Thesampling point upstream of the site had sediments with the highest levels of metals. Nodetectable levels of phenol or PCP were identified in any of the sediment samples.

Aquatic Biota

Attempts were made to sample aquatic biota, but sample takers were unable to collect samples atseveral locations. A portion of Glade Creek next to the 1939 off-site spill area did not appear tosupport an aquatic population due to the gross contamination. Crayfishes were selected for tissueanalysis from three locations. Samples from five other locations consisted of a single compositesample characterized by whole body or eviscerated and decapitated fish of several species.

Results of the aquatic biota sampling (Table 3) showed the presence of phenol and PAHs. Phenolwas found with more frequency in the downstream samples while PAHs were detected withequal frequency in biota upstream and downstream.

Exposure Analysis

IDPH evaluates human exposure pathways to determine the potential for adverse health effects todevelop as a result of exposure to contaminants. Exposure pathways are separated into completedand potential exposure pathways. An exposure pathway consists of five elements: (1) a source ofcontamination; (2) transport through an environmental medium; (3) a point of exposure; (4) aroute of human exposure; and (5) a receptor population.

In completed exposure pathways, all five exposure elements exist, and exposure has occurred inthe past, is occurring, or will occur in the future without some type of intervention. In potentialexposure pathways, at least one element missing, but the missing element could exist. Potentialexposure pathways suggest that exposure could have occurred in the past, could be occurring, orcould occur in the future. An exposure pathway is eliminated if one or more of the elements aremissing and will never be present.

Completed Exposure Pathways

Completed exposure pathways associated with the site are summarized in Table 4. Currently, siteworkers and trespassers can have direct skin contact with contaminated soils. Exposure may alsooccur through inhaling contaminant vapors and contaminated dust. Because the site is fenced andaccess onto the site is controlled by security personnel, trespassing would probably be rare. Onlyone worker who conducts general maintenance and site security activities currently visits the siteregularly.

In the past, area residents are believed to have been exposed to airborne emissions from wood-treating operations at the site. When Koppers was active, area residents reported creosote-likeodors originating from site activities. No off-site environmental data are available to identifywhat contaminants and concentrations were coming from the site at that time. The onlyenvironmental data available were air samples collected in 1987 on the site while the plant wasnot operating. Naphthalene was the only contaminant detected. The highest levels detected werein below ground locations near a waste pile. Low levels of naphthalene were detected in aboveground samples in the plant area; however, the levels detected were not of public health concern.Naphthalene does not cling strongly to silt or sediments, but evaporates into the air. BecauseKoppers is no longer in operation, off-site air is no longer a significant exposure pathway.

Another past completed exposure pathway was through contaminated groundwater at the twohomes north of the site. PAHs were identified in the drinking water wells at both of the homes.Residents of the households could have been exposed to contaminants by drinking the water andbreathing vapors or dermal absorption during showering, bathing, or cooking with the well water.In 1992, a municipal water district began supplying water to those homes.

Potential Exposure Pathways

A potential exposure pathway exists through shallow, contaminated groundwater migrating to thesurface (Table 5). Shallow monitoring wells along the southern site boundary contained elevatedlevels of PAHs, VOCs, and PCP. The water table in that area is about two feet below the surface.Nearby residents, particularly in the neighborhood near the southern site boundary, could comeinto direct contact with contaminated groundwater through sump pumps in basements or shallowexcavations on their property when landscaping or gardening.

Potential human exposure pathways to site contaminants in the impacted streams could includeingestion and dermal absorption of contaminated sediment and aquatic biota (fish and crayfish)in the impacted streams. Glade Creek and Piles Fork Creek typically have low flow rates andbecome intermittent during particularly dry periods, which makes them unattractive forswimming or fishing. Glade Creek and Piles Fork Creek converge and then flow into CrabOrchard Creek about 1 mile downstream of the site. Crab Orchard Creek may be used forrecreational purposes such as wading, swimming, and sport fishing.

Contact with fugitive dusts blown off the site to the surrounding population is a potentialexposure pathway. A residential area is next to the southwest portion of the site. A line of treesseparates the neighborhood from the site and may provide a barrier to dusts. The site is currentlywell vegetated and the only activities on the site that would most likely generate dust are routinemaintenance.

Toxicological Evaluation

PAHs are the chemicals persons have been and may be exposed to in the future. PAHs are acomplex group of chemicals that occur in the environment as mixtures of many components withwidely varying toxic properties. Benzo(a)pyrene (BaP) is one of the most potent PAHs andprobably the most studied. Little is known about many of the other PAHs. USEPA has developedtoxicity equivalency factors (TEFs) for many of the PAHs based on their toxicity relative to BaPto estimate the potential for human health effects from exposure to mixtures of PAHs [9].

IDPH estimated the exposure for a maintenance worker and an occasional trespasser tocontaminated on-site soil and found no health hazards due to this limited exposure.

IDPH compared the total TEFs for all the PAHs detected in the residential well samples to healthguidelines for BaP. Results from the 1989 private well samples showed BaP TEF levels of 0.002parts per billion (ppb) and 0.006 ppb. These levels are less than the USEPA maximumcontaminant level for BaP in drinking water of 0.2 ppb [10].

IDPH estimated the dose to children and adults exposed to PAHs through well water andcompared these values to health guidelines. The estimated exposure to children and adults didnot exceed these guidelines. The cancer risk due to exposure to PAHs was estimated for a 5-year exposure and was found to pose no increased cancer risk.


When Koppers was active, intermittent complaints from individual residents in the surroundingcommunity would describe a creosote odor originating from the facility. The general complaintdescribed the odor as noxious and bothersome, causing nausea and eye and throat irritation. Mostof the complaints appeared to originate from the neighborhood southwest of the facility. Whenthe facility stopped operations, the complaints stopped. No specific community interest group hasbeen identified or has vested interest and concerns regarding the Koppers site. This documentwas available for public comment from August 6 through September 8, 2000 and no publiccomments were received.


IDPH recognizes that children are especially sensitive to some contaminants. For this reason,IDPH included children when evaluating exposures to contaminants at the Koppers site. Childrenare the most sensitive population considered in this health assessment; however, children are not currently being exposed to contaminants from the site.

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