Slurry Explosive Corporation Site,

Columbus


Site History

The Former Slurry Explosive Corporation Site (Site) is located near Hallowell, eleven miles west of Columbus, Kansas, at 3600 NW 74th Street, Columbus, Kansas 66725. The Site originally was part of the coal strip mining in the area and is surrounded by the Mined Lands Wildlife Area which is owned and managed by the Kansas Department of Wildlife, Parks and Tourism (KDWPT). The active manufacturing facility at the Site produces ammonium nitrate-based commercial-grade explosives and blasting agents used in the construction and mining industries. Currently operated by ORICA, the facility currently consists of approximately 10 acres of graveled truck parking and driveways, buildings that house the slurry-based explosives manufacturing, raw material warehouses, equipment maintenance, administration, and a magazine storage area for finished explosive products. Slurry Explosive Corporation's successor company, CHEMEX I, currently holds title to the land beneath the operations and is responsible for complying with the consent order.

The contaminants of concern (COCs) are primarily perchlorate, nitrate, and ammonia in soil, sediment, surface water, and groundwater. The Comprehensive Investigation was conducted in phases between January 2003 and December 2011. A Water Assessment Monitoring Program initiated in 2008 continued semi-annually through December 2018 and is planned to be conducted annually thereafter. The monitoring program included 20 monitoring wells and 7 surface water sample locations. The most recent sampling event conducted in December 2018 showed the highest concentration of perchlorate detected at 100,000 micrograms per Liter (?g/L), above the KDHE Tier 2 Risk-based Standard for Kansas (RSK) of 70.9 ?g/L for the non-residential pathway. The highest concentration of nitrate and ammonia were detected at 1,780 milligrams per Liter (mg/L) (above the Tier 2 RSK of 10 mg/L) and 37 mg/L, respectively.

Corrective Actions

Corrective measures implemented include the installation of Horseshoe Lake Dam in 2004, which provides a physical barrier that protects aquatic wildlife from the contaminants. It also provides a hydraulic barrier that prevents COCs from migrating into the larger lake area. Environmental Use Controls (EUCs) with deed restrictions have been in effect since 2013. The restrictions apply to the fenced-in 10 acres of the Facility property. They include the prohibition of the use of groundwater for domestic or irrigation purposes and provide guidance for soil disposition from excavation activities due to maintenance or construction. An additional EUC for the KDWPT land adjacent to the Site is being prepared to restrict human exposure to impacted groundwater and soil.

The Soil and Groundwater Management Plan was initiated in 2013 in concert with the EUCs on the property. The plan details the procedures to follow when impacted soil and/or groundwater are encountered during maintenance or construction activities. Approximately 500 cubic yards of impacted soil generated by maintenance activities were removed and appropriately disposed off-site.

A Screening-Level Ecological Risk Assessment (SLERA) was completed in 2012, and a Refined SLERA was submitted in 2013 to further evaluate the potential receptor's impact of exposure to perchlorate, ammonia and nitrate. The Human Health Risk Assessment was completed in 2014. GHD Services, on behalf of CHEMEX I, submitted the Corrective Action Study Report, September 2018, which KDHE subsequently approved.

Additional Information

For additional information, please contact:

  • Pamela Green, Environmental Specialist
    Remedial Section/Site Remediation Unit
    KDHE Bureau of Environmental Remediation
    Curtis State Office Building
    1000 S.W. Jackson St., Suite 410
    Topeka, KS 66612-1367
    Phone: 785-296-1935
    Pamela.Green@ks.gov

Site Documents