Former Unocal Chemical Distribution

Facility Site

Site Background

The Former Unocal Chemical Distribution Facility site is approximately 2.4 acres located at 2100 E. 37th Street North in Wichita, Kansas, within the North Industrial Corridor (NIC) site, an area of regional groundwater contamination. From 1953 until 1992 it was a chemical storage and distribution facility, receiving bulk shipments of containerized liquid chemicals by railcar and truck, storing bulk chemicals in aboveground storage tanks, blending bulk chemicals, and packaging and transporting bulk and containerized liquid chemicals to customers. The facility handled aromatic and aliphatic hydrocarbons, chlorinated hydrocarbons, petrochemicals, and others.

An accidental release of tetrachloroethene (PCE) occurred in 1989. Unocal contractors attempted to excavate the spill area; however, excavation would not completely remediate the affected area. The contractors installed a soil vapor extraction (SVE) system. Additional site characterization activities in 1990 and 1991 evaluated the nature and extent of subsurface contamination attributable to the Unocal facility, and as a result of information gathered, in 1992 KDHE and Unocal entered into a Consent Order for Remedial Investigation (RI) and Feasibility Study (FS). The Consent Order outlined the requirements for investigating and evaluating remedial alternatives.

The RI process was conducted in several phases from 1992 to 2007, ending with KDHE's approval of the final RI Report. The investigations identified soil and groundwater contamination originating from several release areas, each distinguishable by a unique set of chemical constituents, and referred to in the RI as Plumelets A-F. Contaminants of concern include but are not limited to: PCE and its degradation products trichloroethene (TCE), cis-1,2-dichloroethene, and vinyl chloride; benzene; naphthalene; 1,1,1-trichloroethane; 1,1-dichloroethene; 1,2,4-trimethylbenzene; 1,3,5-trimethylbenzene; toluene; ethylbenzene; and xylene.

The FS, performed in conjunction with the NIC site FS, was completed and approved by KDHE in July 2009. Evaluation of remedial alternatives focused on saturated soils and elevated dissolved-phase groundwater contamination at and near the facility. Downgradient groundwater contamination in Plumelets A and B is currently being addressed by a groundwater interim measure (IM) interceptor system, part of the response actions performed to date. Any contamination beyond the downgradient extent of the IM system will be further addressed as part of the remedial strategy outlined in the Final Corrective Action Decision for Interim Groundwater Remediation for the NIC Remedial System, currently being designed for implementation by the City of Wichita.

Unocal's contractors have implemented numerous remedial actions since 1989 to prevent, mitigate, or remedy unacceptable risk(s) posed to human health and/or the environment. These actions include SVE, groundwater pump and treat, soil excavation and off-site disposal, source area and downgradient enhanced anaerobic bioremediation via enhanced reductive dechlorination, and a phytoremediation system to address contamination in the western part of the site. Monitoring in some areas has been evaluating natural attenuation. In June 2011 KDHE and Unocal entered into an Environmental Use Control (EUC) Agreement which will protect human health and the environment by placing restrictions, prohibitions, and conditions on land use to reduce or eliminate exposure to remaining contamination.

Based on the FS and other key site documents, KDHE prepared a Draft Corrective Action Decision (CAD) to identify and define the preferred alternative remedy. KDHE is preparing the Final CAD to select a final remedy. All comments received by KDHE during the public comment period, which began February 11, 2013, and ended March 12, 2013, will be addressed by KDHE in the Responsiveness Summary Section of the Final CAD. KDHE also held a public availability session to present information regarding the preferred remedy and solicit public participation on March 5, 2013. KDHE may modify the preferred alternative or select another response action based on new information or public comments.

The Draft CAD and other key site documents are available for the public to review online here at KDHE's Former Unocal Chemical Distribution Facility webpage at, the KDHE offices in Topeka, Kansas, and at the Wichita Department of Public Works - Office of Environmental Health, 1900 E. Ninth Street, Wichita, Kansas 67214. Appointments to review the documents in Wichita may be made by contacting Shawn Maloney at 316-268-8351. To review the documents in Topeka, please contact Holly Burke at 785-296-6242.

Additional Information

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Portions of these reports may have been removed in order to make them web-ready. Complete copies are available by contacting Holly Burke.

KDHE Site Documents

Interim Measure and Recent Monitoring Documents

NIC Remedial Investigation Addendum, November 2005