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Crawford Creek Contamination by Dioxins and Furans



Soils and sediments in the lower Crawford Creek basin, located in Douglas County, Wisconsin, are contaminated by chemicals related to past industrial wood treatment practices at the nearby Koppers' facility. While the levels of dioxins and furans in the soils and sediments of the Crawford Creek basin are not an immediate health concern, the Wisconsin Department of Health and Family Services (DHFS) is unable to conclude whether there are elevated levels of dioxins and furans in fish that pose a public health concern for people who regularly eat these fish. DHFS is requesting further work from the responsible party to adequately support the conclusion that fish sampling is not needed. However, if the responsible party cannot provide such information, DHFS will recommend to the Wisconsin Department of Natural Resources that fish from Crawford Creek and the Nemadji River be tested for dioxins and furans.


The 2001 ATSDR Public Health Consultation on Crawford Creek (1) reported that "soils and sediments in the lower Crawford Creek basin, located in Douglas County, Wisconsin, are contaminated by chemicals related to past industrial wood treatment at the nearby Koppers' facility. People often use areas of the Crawford Creek basin and can come in contact with contaminated sediments and soils. Creosote wastes and polycyclic aromatic hydrocarbons in the soils and sediments of lower Crawford Creek are a human health concern. People should avoid contact with contamination in the creek, and nearby residents need to be informed about the contamination. Until contaminated soils and sediments are cleaned up, warning signs need to be posted to warn hunters, anglers, and others about the health hazards along Crawford Creek." Since then, warning signs have been posted around the affected areas of Crawford Creek, and nearby residents have been informed about hazards in the creek basin.

The public health consultation stated that "dioxins and furans in soils and sediments are not an immediate health concern, but questions remain about the degree and extent of dioxins and furans in the lower Crawford Creek basin." The document recommended that "further testing for dioxins and furans in Crawford Creek soils, sediments, and wildlife should be considered."

Contamination in Crawford Creek came from the Koppers Industries, Inc. (KII), facility, 3185 South County Road "A," Town of Superior, Douglas County, Wisconsin (CERCLIS No. WID006179493). The Koppers' facility is an operating wood treatment installation located on approximately 112 acres in a rural, lightly populated area of Douglas County, approximately five miles southeast of the city of Superior. A number of different businesses have conducted industrial wood treatment operations on the property since it first opened in 1928. KII currently produces wood products (pressure treated with creosote) for industrial railroad line applications. From 1955 to 1979, pentachlorophenol was also used at KII to produce treated wood products.

When DHFS staff first visited the property in May 1997, they inspected a ditch that previously drained runoff from an active portion of KII and carried water-borne contaminated wood treatment wastes away from KII property. Where the drainage ditch leaves KII property, it crosses beneath Hammond Avenue and runs approximately 2,000 feet north-northwest, emptying into the lower portion of Crawford Creek. Crawford Creek, approximately 6.2 miles in total length, flows into the Nemadji River, approximately 1 mile downstream from where the drainage ditch enters the creek. After crossing north of Hammond Avenue, the ditch bisects two residential properties. Visual inspection of the ditch during the site visit revealed horizons of dark, stained soils. Footpaths and a wooden footbridge on one property showed that residents walked along and across the ditch and that residents dug into affected soils when installing the footbridge.

On January 9, 2002, DHFS attended a meeting held by the Wisconsin Department of Natural Resources (DNR) to discuss environmental impacts and human health implications of contamination originating from the KII facility. Also present at the meeting were representatives and consultants for KII, as well as those for Beazer East, Inc, (Beazer), which is the responsible party.

At the meeting, agency and corporate representatives discussed the merits of testing for dioxins and furans in fish found in Crawford Creek and the Nemadji River because the upper strata of aquatic food chains are often sensitive end-points of sediments contaminated with dioxins and furans. DHFS requested further information from Beazer for use in decision making regarding this matter. In follow-up to the meeting, in April 2002, DNR requested additional information on dioxins and furans from Beazer "regarding contaminant fish and wildlife" (2).

In follow-up to this meeting, Beazer's consultant, AMEC Earth & Environment, Inc. (AMEC), prepared a July 2002 report that estimated the concentration of the 2,3,7,8-tetachlorodibenzodioxin (TCDD) toxic equivalency quotient (TEQ) in fish from Crawford Creek and the Nemadji River (3). This estimate used available, site-specific environmental sampling data in an approach that factored a biota-to-sediment accumulation and proportional food chain uptake. Taking into account dioxin & furan levels in Crawford Creek sediments, AMEC estimated that TCDD TEQ concentrations in Crawford Creek forage fish ranged from 1.5 to 7.1 pg/g (picograms per gram or parts per trillion). This estimate was then used to derive a TCDD TEQ in Nemadji River sport fish ranging from 0.45 to 5.3 pg/g. The evaluation pointed out that these estimated concentrations were less than DNR's 10 pg/g "do not eat" advisory level for dioxin. The AMEC evaluation concluded that testing dioxins and furans in fish from the Nemadji River "is not warranted." The Wisconsin DNR requested a review from DHFS regarding the findings of this AMEC report.


During the January 9, 2002, meeting, agency and corporate representatives discussed the value and shortcomings of modeling bioaccumulation in fish tissues of dioxins and furans levels found in sediments, streambanks, and flood plain soils. While modeling was not discouraged at the meeting, DHFS requested that Beazer also search for and present data from case studies with similar levels of dioxins and furans in stream media and the results from subsequent fish tissue analysis of species from the same body of water. It is logical that pairing modeling results with actual sample data from relevant case studies could provide sufficient information for further discussion and a decision about whether a dioxin and furan fish tissue investigation was warranted for the waters of Crawford Creek and the Nemadji River. However, given that the AMEC report did not provide validating data from actual case studies, DHFS is less confident with the estimates by AMEC than if the results were accompanied and supported by the requested examples of actual, site-specific data.

AMEC's estimated dioxin TEQ concentrations are within an order of magnitude of the DNR "do not eat" advisory level of 10 pg/g. This "do not eat" value is used by DNR as a criterion for recommending that the public not eat "any" amounts of the fish from an affected water body. When fish tissue concentrations of TCDD are between 1.0 and 10.0 pg/g, it should not be concluded automatically that it is safe to eat an unlimited amount of such fish. Also, this "do not eat" value is not a threshold criterion that triggers fish tissue monitoring and further sampling. Such a threshold concentration would likely be much lower. Rather, the level is the threshold for informing the public that fish are "unsafe to eat." For other aquatic contaminants that bioaccumulate in fish, such as PCBs, DNR has issued graded fish consumption advisories, with "do not eat" as the most stringent category. For dioxins and furans, DNR has established only a "do not eat" category.


DHFS recognizes that young children and developing fetuses are especially sensitive to exposure to dioxins and furans. In preparing this public health consultation, DHFS has considered the possibility that children and their mothers may be eating fish from Crawford Creek and the Nemadji River and may be exposed to contaminants that originated from KII. DHFS is promoting the further discussion of testing fish specifically to address whether these most sensitive human populations may be exposed to an unsafe level of dioxins and furans.


On the basis of information currently provided by Beazer/AMEC, DHFS cannot confidently conclude that fish from Crawford Creek and the Nemadji River basin do not have unsafe levels of dioxins and furans. For that reason, fish in those areas pose an indeterminate public health hazard. DHFS has respectfully requested Beazer and AMEC to provide sufficient stream media and fish tissue data for furans and dioxins from similar cases to adequately support their Beazer and AMEC's estimated results and conclusions, but these data have not been provided.


In the absence of data that validate AMEC's modeling technique, DHFS recommends to DNR that fish from certain portions of the Crawford Creek and Nemadji River basin be tested directly for the appropriate form of furans and dioxins.


  1. When adequate data are made available, DHFS will meet with Department of Natural Resources and responsible parties to examine data validating AMEC's model. DHFS will then determine whether the data are sufficient or whether to recommend that fish from Crawford Creek and the Nemadji River be tested for dioxins and furans.

  2. DHFS will continue to work with the Wisconsin Department of Natural Resources, the Douglas County Health Department, and other parties to ensure that affected areas of Crawford Creek are properly posted and nearby residents are educated about the existing contamination in soils and sediments around the Koppers facility and in Crawford Creek.

  3. DHFS will continue to evaluate the public health implications of new environmental and wildlife sampling data as they become available.


  1. Agency for Toxic Substances and Disease Registry. Public health consultation on Crawford Creek contamination, Koppers Industries Incorporated, Superior, Wisconsin. EPA Facility ID: WID006179493. Atlanta, GA: US Dept of Health and Human Services; 2001 Aug 24.

  2. Wisconsin Department of Natural Resources. Correspondence from J Hosch to J Patarcity, Beazer East, Inc. WDNR review of RCRA facility investigation, supplemental investigation activities, Koppers Industries Inc., Superior Wisconsin. Superior, WI: 2002 Apr 11.

  3. AMEC Earth & Environment, Inc. Correspondence from A Gargani to J Hosch. Westford, MA:.2002 Jul 10.


Henry Nehls-Lowe, MPH
Bureau of Environmental Health
Division of Public Health
Wisconsin Department of Health & Family Services


This Public Health Consultation on Crawford Creek Contamination by Dioxins and Furans was prepared by the Wisconsin Department of Health and Family Services under a cooperative agreement with the Agency for Toxic Substances and Disease Registry (ATSDR). It is in accordance with approved methodology and procedures existing at the time the public health consultation was begun.

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

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

Roberta Erlwein

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