Site Narrative:
The Tri-County Public Airport (TCPA) Site is located in rural Morris County. The property was developed in the early 1940s as the Herington Army Airfield (HAAF) and deactivated in 1946. The facility was used for processing aircraft crews and heavy equipment, and contained several buildings, including three general maintenance hangars, a large sub-depot (Hangar 1) and a motor pool. The property ownership was conveyed to the City of Herington in 1948.
The TCPA Site was discovered in connection with assessment work conducted between 1994 and 1996 by the Army Corps of Engineers (ACOE) investigating petroleum contamination associated with former site operations of HAAF. During the investigation, the chlorinated solvent trichloroethylene (TCE) was discovered in groundwater. Beech Aircraft Company (Beech), predecessor to Raytheon Aircraft Corporation (Raytheon), leased four hangars and several other buildings at the Site from 1950 until the early 1960's. Beech used TCE as a solvent in degreasers located in Hangars 1 and 4.
In 1989 TCE and carbon tetrachloride (a grain fumigant) were detected in groundwater samples collected in the nearby town of Latimer located three miles northwest of the TCPA Site. These findings along with the ACOE investigation findings prompted a series of investigations by EPA and KDHE at the TCPA Site and nearby private wells. The CT source was determined to be associated with the Latimer Agri-Services facility, and groundwater monitoring is currently being conducted by KDHE's State Water Plan/Orphans Site Program as the Latimer Groundwater Contamination Site (See Project Code: C5-064-70590).
Due to the extent of groundwater impacts in residential wells, affected residents were provided bottled water in 1997 until carbon filtration systems were installed and operational in 2000. A water supply line was constructed and completed in 2006, with residents in Latimer and nearby areas connected to the supply line. Area private water well sampling continues to date.
In 2000 Raytheon entered into a Consent Order (CO) with KDHE to perform a Remedial Investigation (RI) and Feasibility Study (FS) for the TCPA Site. The CO was amended in 2009 and 2013 to address Respondent company name changes. The RI was initiated in 2001 and completed with approval of the RI Report in 2008, and a Human Health Risk Assessment and Screening Level Ecological Risk Assessment were completed with approval of the Reports in 2009. A residential indoor air assessment was conducted in 2009 with contaminants of concern not detected above residential indoor air Kansas Risk-Based Standards, and Report approved in 2009. A FS Report was initially approved in 2010, and a FS Addendum Report was approved in 2015 that included revised recommended remedial alternatives for the Site.
In addition to private well remediation activities, source abatement actions and several pilot tests and interim remedial measures (IRMs) have been or are being conducted at the Site to address Site contamination and/or support the FS, which include the following: a soil removal action at Hangar 1 Area in 2005 as part of a Unilateral Administrative Order issued by EPA in 2004; MNA assessment (2011); ERD and tracer study (2012-2014); in-situ chemical oxidation permanganate injections IRMs (2009-present); and soil vapor extraction (SVE) pilot test/IRMs (2011-present).
All work at the Site ceased when Respondent (Hawker Beechcraft Corp.) filed for bankruptcy in 2012, and in 2013, upon emerging from bankruptcy and reorganization, Beechcraft Corporation (BC) resumed Site IRMs and sampling activities. On September 15, 2015, BC entered into a CO with KDHE to perform Corrective Action Plan/Corrective Action tasks at the Site. KDHE prepared a draft Corrective Action Decision (CAD) for the Site which outlined KDHE's preferred remedy for addressing contamination at the site. KDHE published the Final CAD on December 17, 2020 following a public comment period. Work continues at th e site as of July of 2025, monitoring has been conducted and shows a steady decline in contaminant levels. Additional in-situ chemical oxidation injections were completed August 2025. |