ONEOK FMGP - Concordia Site
The One Gas Inc. (ONE Gas), formerly known as ONEOK, Inc., Former Manufactured Gas Plant (FMGP), Site (Site) is located southeast of the intersection of Mill and Republican Streets, Concordia, Kansas (approximately 1,000 feet south of Lost Creek and a mile south of the Republican River (Figure 1). The earliest record of deeds citation notes that the Concordia Gas Company took title to the property in 1915. Manufactured Gas operations ceased in or around 1930 when the Gas Corporation of Concordia was acquired by the Kansas Pipe Line and Gas Company. The property is currently zoned as Light Industrial and is now owned by the Abram Ready Mix Plant. No buildings associated with the FMGP operations remain.
Prior to and since the construction of the MGP, the properties around the Site have been used for industrial and residential purposes. The properties north of the Site have been occupied by:
- Concordia Roller Mills and farther north the Republican River from 1887 to 1905.
- A flour warehouse and dwelling located on the mill property in 1905.
- The Concordia Electric Light Company, located to the northeast from 1889 to 1911. The Concordia Roller Mill moved south of the electric plant in 1905. The facility was used as a carpentry shop in 1917 and a concrete products plant in 1927.
- Kansas Power and Light Company, located at the northeast corner of Republican and Mill Streets, was used for pole storage in 1946 (Union Pacific Railroad, 1946).
The properties to the east of the Site were used by the following facilities:
- The Concordia City Water Works operated a plant with five driven wells from 1889 to 1911. The 1905 Sanborn Map indicates the facility pumped water from a system of 24 well points. No evidence has been found to indicate the wells are still present.
- A spur of the Union Pacific Railroad was built directly east of the Site by 1905.
- Boyd Oil Company and Standard Oil Company occupied the east half of Block 176 from 1927 until at least 1993. Currently, there are no existing oil operations on this property; however, some ASTs, concrete saddles, and former facility buildings remain.
On behalf of the United States Environmental Protection Agency (USEPA), a consultant/contractor investigated the Site and recorded the results in the Site Investigation Report for Site Assessment Activity at Concordia FMGP (January 1993). The sample results identified heavy metals, semi-volatile organic compounds (SVOC), and volatile organic compounds (VOC) were located in the subsurface soil and groundwater. Elevated levels of zinc and mercury and six SVOCs were detected in the subsurface soil above background levels. Laboratory results also identified eight dissolved metals, five SVOCs, and 22 VOCs above background levels or above maximum contaminant levels (MCLs) in groundwater samples.
ONE Gas completed a Site Investigation characterizing soils in 2003. Two exploratory trenches delineated a below-grade gas holder, tank (unknown use), cistern, and other process equipment locations. The primary contaminants detected were Polynuclear Aromatic Hydrocarbons (PAH), Benzene, Toluene, Ethylbenzene, and Xylene (BTEX), arsenic and lead, exceeding Kansas Department of Health and Environment (KDHE), Risk-based Standards for Kansas, RSK Manual - 5th Version (October 2010, revised March 2014 and September 2015) (RSK) residential Tier-2 values for one or more PAH compounds.
- Diagram of the Concordia Former FMGP (PDF), showing current and historical structures.
Five groundwater monitoring wells (CMW-01 to CMW-05) were installed between June 5, 2007, and August 29, 2007. These monitoring wells primarily line the perimeter of the Site. These wells have been routinely sampled beginning in 2007 through the most recent groundwater sampling in August 2020. The only analytical constituent that has been consistently detected above KDHE Residential or Non-Residential Tier II RSKs values is arsenic (0.01 milligrams per liter (mg/L)). Arsenic has been detected at concentrations ranging from 0.011 mg/L in the sample collected from CMW-02 to 0.049 mg/L in the sample collected from CMW-05 during the August 27, 2020 event.
ONE Gas completed a background assessment of arsenic levels in groundwater in August 2011. Analytical results ranged between 0.0020 milligrams per liter and 0.0062 mg/L. The RSK Tier-2 Residential level for Arsenic is 0.01 milligrams per Liter (mg/L). The background assessment results note that the background arsenic levels do not appear to contribute to the on-site arsenic concentrations in groundwater.
In 2008 ONE Gas completed an Interim Removal Action (IRA). The IRA excavated approximately 1,604 tons of soil, ending when groundwater was encountered at 23 feet below the ground surface. The excavation was lined with a geotextile barrier and backfilled/compacted with clean fill. The surface was graded with six inches of crushed rock to match the existing grade. Confirmation sampling indicates that the IRA successfully removed most of the soil impacted above RSK Tier 2 levels. Existing building foundations and concrete slabs prevented the complete removal of the contaminated soil.
To prevent possible future exposure to soil and groundwater contamination ONE-Gas recorded an Environmental Use Control Agreement (EUCA) (08-EUC-0038) on December 1, 2009, with the Cloud County Register of Deeds, restricting future land use to non-residential and prohibiting drilling, construction, or use of water wells for domestic purposes.
The remedial alternative identified in the Final ADS (September 6, 2019) was Alternative 2 - long-term groundwater monitoring which included all previously completed excavation, response actions, and the Environmental Use Control (recorded with the Cloud County Register of Deeds. This remedy has proven to be protective of human health and the environment. Therefore, on the basis of the Administrative File summarized above, KDHE recommends that the Site be Conditionally Closed in accordance with KDHE Bureau of Environmental Remediation (BER) Policy, BER-RS-024, Site Closure in the State Cooperative Program, (February 2015).
The ADS was available for review from April 5, 2021, through April 20, 2021, during the 15-day comment period held to solicit written comments from the public. Any comments received will be addressed in the final ADS.
For additional information, please contact:
John Cook, KDHE-BER Project Manager