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The Ace Services, Incorporated (Ace) facility, a former metal plating operation, site is in Colby,Kansas, in Thomas County. The company operated between 1969 and 1989. Plating wastes werereleased during operations. The results of sampling indicate that some of the releases entered thegroundwater system and affected water quality in a nearby public well and also some nearbyprivate wells east of the property. None of those wells are now in use. Recent sampling of waterfrom private wells farther east, at and beyond the city limits, showed some contained low levels ofcontaminants; it is not possible to determine whether those contaminants are associated with thesite. The U.S. Environmental Protection Agency and Kansas Department of Health andEnvironment oversaw removal actions conducted in the plating building and on the surroundingterrain. A chemical storage building and wastewater treatment building were demolished andremoved from the property. Only the machine shop building and plating building remain. Localofficials have suggested that the plating building might be reused as a county recycling center, buta specific reuse has not been declared.

The Agency for Toxic Substances and Disease Registry has concluded that the site once posed apublic health hazard for former workers principally because of exposures to chromium and lead inprocess wastes, other residues, and soils. The site currently poses an indeterminate public healthhazard because of uncertainty about whether the facilities will be reused and the specific type ofreuse and uncertainty about whether there will be additional removals or remediations. Nitrate,which is not associated with the site, had been reported at elevated levels in two private watersupply wells in the site area within the city limits; those owners now are connected to the publicwater system. About 4 percent of private wells that a state-funded group has sampled in ruralparts of the county also have shown elevated nitrate. That group reports the elevated nitrateresults to the well owner, identifies potential effects on infants, and recommends that the ownerhave the well water reanalyzed for verification.

This document was released for public comment on April 18, 1996. The comment period endedMay 24, 1996, – no comments were received. A few persons were asked to evaluate documentclarity and included some programmatic and technical comments in their response.


The Agency for Toxic Substances and Disease Registry (ATSDR), located in Atlanta, Georgia, isa federal agency within the U.S. Department of Health and Human Services. ATSDR, under theComprehensive Environmental Response, Compensation, and Liability Act of 1980 (CERCLA),conducts public health assessments for sites the U.S. Environmental Protection Agency (EPA)proposes for its National Priorities List (NPL). In 1995, the EPA announced its proposal toinclude the Ace Services site on the NPL. Therefore, ATSDR has, under its mandate, evaluatedthe public health significance of this site by considering whether health effects are possible and hasrecommended actions to mitigate possible future exposure.

A. Site Description and History



The Ace Services, Incorporated (Ace) facility, a former metal plating operation, is located at 345Convesse Avenue, Colby, Kansas, in Thomas County, on the west side of an unnamedintermittent tributary of Prairie Dog Creek. The site location is shown in Figures 1 and 2 (Appendix A). The company operated between 1969 and 1989. Plating wastes were releasedduring operations. Sampling results show that some of the releases contaminated buildingcomponents, soil, and the wastewater lagoon area. Some contaminants entered the groundwatersystem, which flows in an easterly direction. The areal extent of the contaminated groundwater isnot clearly defined. In 1980, water being obtained from a municipal well, Colby Public WaterSystem Well #8, about 1,000 feet eastward of the site, was found to contain elevated levels ofchromium. A few of the private wells sampled farther east were also shown to contain contaminated groundwater (1, 2).

The facility once had five contiguous components, which ATSDR categorizes as follows:
Main buildings (approximate locations shown on Figure 2)

  • plating building (also contains a small office area used by plating staff)
  • machine shop building (also contains separate shot blast, grinding, shipping, and general office areas)
Support components (formerly on east side of main buildings)

Only the plating and machine shop buildings remain.

    General Chronology of Events

Municipal Well #8 was drilled in 1953 to a depth of 250 feet. Ace began operations in 1969. From 1969 to 1975 chrome plating wastewater was discharged from the east side of the buildingsdirectly onto the ground surface. A citizens's complaint was filed in 1971 with the KansasDepartment of Health and Environment (KDHE). Sampling of discharged wastewater indicatedthe presence of chromium. In 1974 and 1975, concrete vats were installed to capture platingsolutions and an unlined earthen wastewater evaporation lagoon was constructed to receivewastewater. Wastewater, which was stored in the lagoon, seeped into the ground andcontaminated the underlying soil and groundwater. Inside the plating building, contaminatedsolutions also leaked into soils beneath the floor (1).

In early 1980, an analyses of water from Well #8 showed an elevated level of total chromium. The well was removed from service later that year (3).

In 1980, Ace installed a recovery well at the site to be used to extract contaminated groundwaterfrom the Ogallala Aquifer. This recovery system never became fully operational. In 1981, Aceexcavated approximately 2,200 cubic yards of sludge and contaminated soil from the lagoon area. Information about health and safety practices for that activity is unavailable. Ace ceasedoperations in 1989. KDHE installed three monitoring wells in 1990 (1, 4).

In March 1992, a KDHE contractor removed plating vats and bulk liquid and solid wastes fromwithin the plating and wastewater treatment buildings. Efforts to decontaminate concrete wereonly partially successful (5). Those activities were conducted under terms of a health and safetyplan. Workers wore protective clothing and respirators (Level C protection) (6). EPA completeda removal action in July 1994. Those activities consisted of demolishing the chemical storage unitand wastewater treatment building. In the plating building, the concrete floor was washed withchemicals intended to convert residual hexavalent chromium [chromium (VI)] to trivalentchromium [chromium (III)] (7). Follow-up testing has not been conducted to confirm theeffectiveness of the floor treatment. Concrete plating troughs were removed and contaminatedsoils beneath the plating building were excavated. Auxiliary columns and beams were installed toimprove building stability. Some contaminated soils that could not be fully excavated withoutendangering the structure were left in place and covered with imported soil. Concrete then waspoured to reform the floor (8). Substantively contaminated soils also were excavated in thelagoon vicinity; the excavated area was covered with imported soil and shaped to enhancedrainage. EPA personnel report that workers performed those activities wearing protectiveclothing and respirators (Level C protection). Soil and air Action Levels prescribed for theremoval were (9):

Soil Total chromium 1,500 parts per million (ppm)
Lead 500 ppm
Air Total chromium 100 micrograms per cubic meter (g/M3)
Lead 30 g/M3

Contaminated materials handled during the removals were shipped off site for disposal except forabout 3,000 gallons of wastewater, which was treated on site and discharged to the city'swastewater treatment plant. Sludge disposal in 1981 was to the county landfill east of town(Figure 1) where the materials were enclosed in plastic sheeting within a trench and then coveredwith soil. KDHE personnel report that disposal of materials in 1992 was to a facility permitted toreceive hazardous waste. Disposal of materials from the 1994 activities also was to a facilitypermitted to receive hazardous waste (1, 4, 8).

Studies conducted by EPA in 1994 indicated that the sludge disposed in 1981 in the countylandfill in a plastic enclosed trench would not leach substantively, was not considered a hazardouswaste pursuant to the Resource Conservation and Recovery Act (RCRA), and could remain inplace. At the Ace site, EPA intends that a deed restriction or other type of institutional controlshould be placed to keep a future property owner from disturbing any contamination that mightremain beneath the concrete floor and beneath fill soils (8).

    Current Site Features

During the 1995 site visit, ATSDR, EPA, and KDHE staff entered the plating building to observeits current condition. The building was empty except for some large generators and empty steelplating vats. The removal activities (excavation and washing) were described, and observationsshowed that a portion of the floor had a yellowish and greenish tint that likely is caused bychromium leaching from the concrete. A small office area in the northwest corner of the platingbuilding that was excluded from removal activities was seen to be very dusty. A large doorwaythat had once connecting the plating and the machine shop buildings has been effectively sealed. The former lagoon area has been shaped to convey runoff into the tributary. ATSDR staff saw nophysical evidence of the former wastewater treatment building and chemical storage unit that hadbeen demolished and removed from the site. The machine shop building and plating building arelocked (thereby preventing access). Difficult terrain and thick vegetation in the former lagoonarea make access there unattractive.

    Future Site Use

A number of possible future uses are being considered. In September 1995, EPA asked ATSDRto comment about the site being used as a recycling center that would operate weekends and bestaffed by volunteers. Also, in January 1996, ATSDR was asked by EPA for an opinion about usefor indoor athletic practice, a student dormitory, or equipment maintenance. ATSDR preparedtwo public health consultations (dated November 28, 1995, and January 30, 1996, respectively)that responded to those issues (10, 11). ATSDR's findings regarding facility reuse aresummarized in the Conclusions and Recommendations sections of this assessment.

B. Site Visit

Dr. Shan-Ching Tsai and Don Gibeaut of ATSDR and several representatives of KDHE and EPAvisited the site and vicinity on September 11 and 12, 1995. Pertinent information obtained duringthe visit is described in appropriate sections of this document.

C. Demographics, Land Use, and Natural Resource Use

Land Use

ATSDR staff observed that commercial and government facilities predominate in the site vicinity. A portion of the facility property lies within the 100-year floodplain (3). The county landfill,where sludge was disposed, is south of U.S. Route 24 about a mile east of the city limits in a ruralagricultural area. Along that highway, the city limits are located about 3,000 feet east of the site. To the north and south of the highway, the city limits bend toward the west and are closer to thesite.


The 1990 census indicates that the population of Colby is 5,396. The area beyond the city limitsis rural. An estimated 340 rural residents are within 4 miles of the site (1). ATSDR, through itsGeographic Information System analyses of 1990 census data estimates the populationdistribution within 1 mile of the site as follows:

  • Total resident population       2,970
  • Children up to 5 years              290
  • Adults 65 and older                 630
  • Percent white                            98.6
  • Percent Hispanic                         0.9

The residences closest to the site (total of eight) were observed to be several hundred feet to thesoutheast, northwest, and southwest. In addition, a small church is about a 100 feet northeast ofthe plating building. The nearest developed public park is about 1,500 feet northwest. Theclosest undeveloped park is about 2,000 feet southwest. There are no schools, nursing homes, orhospitals in the vicinity.

At the county landfill, the closest residences (total of three) are about a half mile south of thatproperty and a mile eastward. No park or health facilities are in the vicinity.

Natural Resource Use

Potable public water supplies in the Colby area are obtained from seven wells that extend into theOgallala aquifer that underlies the region. The aquifer also provides substantial water forirrigation and industry. In the site vicinity, the base of the Ogallala Formation is about 200 feetbelow ground surface; the depth to water is about 80 to 100 feet; and groundwater flowseastward. ATSDR staff learned from Colby water officials that the municipal system supplies thecommunity from a large storage tank that is refilled daily; each well is pumped on a rotatingschedule for durations of up to 24 hours. Thus, water from the well being pumped is blended inthe tank with water remaining from the previous days inflows from other wells. The closestpublic well is about 2,000 feet northwest of the site; none are east of the site, in the direction ofgroundwater flow. The formerly used Well #8, which was disconnected from service in 1980, islocated down gradient, about 1,000 feet east of the property (1).

ATSDR staff learned from Colby's director of public works that the water distribution lines in thesite vicinity extend to the city boundary, which is as far as 3,000 feet east of the site. Staff alsowere told that everyone between the site and the eastern city limits (in the direction ofgroundwater flow) is supplied by the public system except for one home that still uses a well. That home is in a residential area south of U.S. 24, about 2,500 feet east of the site. Homes andbusinesses east of the city limits rely on private wells except for a trailer court which hasconnected its system to the public water line. ATSDR staff saw several homes along Route 24immediately east of the city limits that use wells for their potable water supply.

The unnamed tributary east of the property discharges into Prairie Dog Creek several milesdownstream. Both are intermittent streams. The specific location at which the streams mightsupport a fishery is not known, but is estimated to be at least 15 miles from the site (1).

D. Health Outcome Data

The Kansas Department of Health and Environment at Topeka, Kansas maintains an annualsummary of vital statistics for all counties in the state. Please refer to the Public HealthEvaluation section of this document for a discussion of health outcome data for Thomas County.


None of the persons attending the public availability sessions voiced any health-related concerns.

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