ONEOK FMGP - Concordia Site

Site Background

The ONEOK Former Manufactured Gas Plant (FMGP) Site is located southeast of the intersection of Republican and Mill Streets and is zoned light industrial. The Site is currently owned by the Abram Ready Mix Plant (Abram). Abram Ready Mix operates an above ground fuel tank, which services an adjacent fuel pump island located near the north entrance onto the Site.

The FMGP operated from 1913 to 1930, first by Eaken & Donelan, then Concordia Gas Company. In 1930, the Gas Corporation of Concordia was acquired by the Kansas Pipe Line & Gas Company of Salina, Kansas.

Investigation Findings

The United States Environmental Protection Agency, through a contractor, conducted a site investigation in 1993. This investigation analyzed soil and groundwater samples, identifying metals, semi-volatile organic compounds (SVOCs) and volatile organic compounds (VOCs) in subsurface soil and groundwater.

In September 2003, Burns & McDonnell conducted a Site Investigation (SI) which included two exploratory trenches. This investigation identified the location and depth of the below-grade gas holder, but did not located an alleged cistern. It also collected soil samples from inside the FMGP building and from within the below-grade gas holder and an adjacent unknown structure. Sample analysis identified polynuclear aromatic hydrocarbons (PAHs); benzene, toluene, ethylbenzene, and xylene (BTEX); arsenic; and lead as primary contaminants. A previously unknown structure on the north side of the gas holder contained crushed rock, sand, and fill material with some water and a black, viscous liquid five feet below ground surface (bgs), presumably the bottom of the structure.

Three surface soil sample had concentrations of one or more PAH compounds that exceed the RSK Tier 2 values. Additional, subsurface soil samples collected in the vicinity of the former purifiers were analyzed for arsenic and lead. Detectable concentrations of both metals were reported in each of these samples below RSK Tier 2 values.

In 2008, Burns & McDonnell completed an IRA (interim removal action) at the Site. The objectives of the IRA were: remove potential sources of soil and groundwater impacts by excavating MGP residuals and impacted material in and/or around select former MGP structures; and, manage and dispose of the excavated materials in accordance with KDHE and USEPA regulations. The excavations were terminated approximately 23 feet below the ground surface where groundwater was encountered. The presence of existing building foundations, concrete slabs and other Site impediments prevented the complete removal and disposal of all impacted soil. Approximately 1304 tons of soil was removed from the Site. Several soil confirmation samples were collected from selected locations along the sidewalls and floor of the excavations. Results from these confirmation analyses noted that although some analytes were present at concentrations above laboratory method detection limits, the concentrations in the remaining soil within the area of excavation do not exceed cleanup goals except for one constituent. Naphthalene remains at a concentration (1.3 mg/kg) exceeding the Tier 2 RSK residential (0.349 mg/kg) and non-residential (0.659 mg/kg) soil-to-groundwater pathway value. A geotextile barrier was placed in the excavation and the excavation was backfilled with clean fill. The surface was graded with six inches of crushed rock to match the existing grade. KDHE concluded that the IRA was successful in removing a majority of FMGP contaminated materials. The cost to complete the IRA was $434,861.69.

Five groundwater monitoring wells, CMW-01 through CMW-05, were installed between June 5, 2007 and August 29, 2007. These wells have been sampled multiple times including: 2007, 2009, 2010, 2013, and 2015. Based on information from these sampling events groundwater beneath the site flows to the northwest. The only constituent that has consistently been detected above RSK Tier 2 residential and non-residential values (0.01 milligrams per Liter (mg/L)) is arsenic ranging between 0.011 mg/L and 0.0202 mg/L.

One-Gas completed an assessment in August 2011 of background arsenic levels in groundwater. Analytical results for background arsenic ranged from 0.0020 mg/L to 0.0062 mg/L. The RSK Tier 2 Residential levels for arsenic is 0.01 mg/L. Thus the background samples were below the RSK Tier 2 Residential levels indicating that groundwater from off-site is not likely impacting on-site groundwater.

To address the more immediate IRA goal of preventing future exposure to possible residual contamination (both soil and groundwater), ONE-Gas recorded with the Cloud County Register of Deeds on December 1, 2009 and Environmental Use Control Agreement (EUC). Conditions of the EUC include: The Property shall not be used for residential purposes of any type; the Owner shall not allow water wells to be drilled, constructed, or used on the Property for domestic purposes. Additionally, the Owner agrees to provide post-construction maintenance of the ground surface to facilitate surface water runoff and drainage at the area on the Property where source removal was conducted.

Anticipated Activities

Based on summarized analytical data compiled during the various phases of assessment/investigation and the interim removal action (soil), there continues to exist minimal residual soil and limited groundwater contamination above the RSK Tier 2 values.

The proposed remedial plan for the Site is based on the remedial alternative analysis performed in the Corrective Action Study (CAS). The CAS-recommended remedial alternative is Alternative 2, which includes all previous response actions, the recording of an Environmental Use Control Agreement on the FMGP property and continued groundwater monitoring.

The recommended response action at this Site is Response Alternative 2 - LTM with EUCA. This option is the most cost effective, viable response action and provides suitable protection to human health and the environment. This remedy provides continued performance monitoring of selected groundwater monitoring wells and parameters. KDHE may modify this plan in response to public comments received during the public comment period and/or if new information becomes available.

A Public Information Strategy for the Site was developed by KDHE and includes implementation criteria for public participation requirements. Public notice of the availability of the Draft Agency Decision Statement will be published in the Concordia Blade Empire on August 12, 2019. The Draft ADS will be available for review at the Frank Carson Library, 703 Broadway, Concordia, Kansas 66901 from August 12, 2019 through August 27, 2019. Pertinent documents related to the Former Manufactured Gas Plant site are also available for review at the KDHE offices in Topeka, Kansas during this public comment period. To review documents in Topeka, please contact John K. Cook, Professional Geologist, at 785-296-8986. Public comments on the Draft ADS may be submitted to KDHE in writing during the 15-day public comment period at the address listed below.

Kansas Department of Health and Environment
Bureau of Environmental Remediation
Site Restoration Unit
1000 SW Jackson, Suite 410
Topeka, Kansas 66612-1367
Contact - John K. Cook, Professional Geologist
(785) 296-8986

Comments on the Draft ADS may also be submitted to KDHE by electronic mail to Comments sent by electronic mail must be received by KDHE by 5:00 p.m. on August 27, 2019. Through this process, the public and other interested parties are given the opportunity to provide input on the proposed corrective action strategy for the Site before the Agency Decision Statement is finalized.

KDHE has prepared an Agency Decision Statement (ADS) which identifies and defines the preferred remedial alternative for the Site. A 15-day public comment period will run from August 12, 2019 through August 27, 2019. The draft ADS and other key documents are available for the public to review online below, at the KDHE offices in Topeka, Kansas, and at the Frank Carson Public Library, 702 Broadway, Concordia, Kansas 66901.

Site Documents