Reade Manufacturing, now known as Reactive Metals & Alloys Corp.(REMACOR),owned and conducted a herbicide blending/formulating operation at the site during the period extending at least from 1942-63. U.S. Borax, Inc.(U.S. Borax), leased the site from REMACOR during the period 1963-68 and conducted a herbicide blending/formulating operation at the site. Habco, Inc., acquired the site in 1968 and conducted a herbicide blending/formulating operation at the site during the period 1968-86. In 1986, K.C. 1986 Limited Partnership, an entity affiliated with Habco, Inc., acquired the site. The site has apparently not been in active operation since 1986.
In 1989, Hardee’s Food Systems, Inc., acquired a leasehold interest in the site, and contracted with Terracon Environmental, Inc., to perform an environmental assessment of the site. That assessment indicated the presence of significant soil, groundwater and building contamination on or near the site. Primary contaminants found included arsenic, 2,4-dichlorophenoxyacetic acid (2,4-D), 2,4,5-trichlorophenoxyacetic acid (2,4,5-T), and pentachlorophenol.
In September of 1993, the Missouri Department of Natural Resources (MDNR) and the site owner, K.C. 1986 Limited Partnership, entered into a consent agreement which provided for K.C. 1986 Limited Partnership to investigate the site and submit to the MDNR for approval a written remedial action plan. As part of the investigation, conducted by K.C. 1986 Limited Partnership pursuant to the consent agreement, several sampling events aimed at better defining surface, subsurface and building contamination were conducted.
In 1996, the site was referred to the U.S. Environmental Protection Agency (EPA) by the MDNR. The EPA conducted a time-critical removal action in May 1996 to reduce or eliminate human exposure to arsenic-contaminated soil at the site through the exposure routes of ingestion, inhalation, and dermal contact. The action consisted of the placement of geofabric and crushed rock on areas of the site which were not covered (e.g., concrete), and the placement of additional fence around the perimeter of the site.
In December of 1996, the EPA entered into an Administrative Order on Consent with U.S. Borax. Under terms outlined in the Administrative Order on Consent, U.S. Borax agreed to, inter alia, prepare an Engineering Evaluation/Cost Analysis (EE/CA) that focused on contaminant source area removal at defined areas of the site.
Several sampling events were conducted by U.S. Borax from the period 1997 through 2001. Information from these sampling events was used primarily to support conclusions and determinations in the EE/CA. The sampling events conducted by U.S. Borax, as well as sampling events conducted by previous parties, can generally be summarized as follows:
Soil - Soil sampling has consistently shown the presence of several inorganic and organic compounds above background levels. To date, however, arsenic is the contaminant which has proven to be the most widespread as well as posing the most significant health threat. Arsenic concentrations have been detected at levels as high as 121,000 milligrams per kilogram (mg/kg), and have typically ranged from several hundred to several thousand mg/kg. These levels have been seen at depths ranging from ground surface to approx. 15-20 feet below ground surface. In addition, 2,4-D, 2,4,5-T and pentachlorophenol have routinely been detected in the soil analyses, in much lower average concentrations than arsenic. Other contaminants have been detected, but concentrations have generally been low.
Groundwater - Groundwater sampling has been similar to soil sampling data; highest contaminant concentrations have been arsenic (30,908 mg/l), 2-4-D (94 mg/l), 2,4,5-T (320 mg/l), and pentachlorophenol (8,062 mg/l).
Building - Concrete samples and wipe samples taken from the former blending facility building have indicated arsenic at 1,480 mg/kg and 171 ug/100 cm2, respectively.
The EE/CA was documented in a report entitled “Engineering Evaluation/Cost Analysis, 2251 Armour Road Site, North Kansas City, Missouri,” dated February 2002.
