OSWER/OSRTI

Washington, DC 20460

NATIONAL PRIORITIES LIST (NPL) 

***Proposed Site*** December 2013 

WALKER MACHINE PRODUCTS, INC. Collierville, Tennessee 

Shelby County 

 Site Location:

The Walker Machine Products Site is located at 459 Washington Street. The property is approximately 5 acres in size 

situated along the south side of Washington Street east of downtown Collierville. There are several industrial properties in 

the vicinity; however, there is a residential neighborhood to the south, across Halley Street. 

 Site History:

Walker Machine produced automated machine screw products from 1953 until approximately 2002. Langley Wire Cloth 

has operated at the facility since 2006 manufacturing filters from wire cloth. This operation is not associated with Walker 

Machine Products and is not the source of contamination at the site.

 Site Contamination/Contaminants:

Walker Machine Products used chlorinated solvents, including tetrachloroethene (PCE) and 1,1,1-trichloroethane (TCA), to 

clean the finished products. A 1987 Tennessee Occupational Safety and Health Administration (OSHA) Inspection Report 

stated the company was draining spent solvent onto the ground and into the sewer drain in the rear of the building. An 

oil/water separator was used by Walker Machine Products which received solvent waste as well. The primary source of soil 

and ground water contamination is found in the area of the oil/water separator. 

 Potential Impacts on Surrounding Community/Environment: 

Soil and ground water below the site has been contaminated with PCE, TCA and their degradation products. The ground

water contaminant plume has migrated off-site under the adjacent industrial property-Witt International. The city of 

Collierville provides drinking water to residents from five drinking water plants that pump water from twelve different 

wells. Well field #1, consisting of 3 wells, is approximately 1⁄2 mile from the site, and only 1⁄4 mile from the documented 

edge of the ground water contaminant plume. This well field services 12,284 residents. 

 Response Activities (to date):

The EPA and the Tennessee Department of Environment and Conservation (TDEC) first investigated the site in 2007, 

collecting surface and subsurface soils and installing and sampling monitoring wells. From 2010 to 2012 the EPA and 

TDEC installed additional monitoring wells and soil gas sampling to try to determine the extent of soil and ground water 

contamination. Although the ground water contamination extends below the Witt International property, no sources of the 

contamination were found on the Witt International property. The source of the contamination was determined to originate 

on the former Walker Machine Products property. 

 Need for NPL Listing:

The state of Tennessee referred the site to the EPA because the ground water contamination has migrated and is 

approximately 1⁄4 mile from the city of Collierville Well #1. Other cleanup alternatives were evaluated, but are not viable at 

this time because Walker Machine Products is closed and the owner is deceased. No other regulatory programs are able to 

address the ground water contamination. The EPA received letters of support for placing this site to the NPL from the state.

[The description of the site (release) is based on information available at the time the site was evaluated with the HRS. The description may 

change as additional information is gathered on the sources and extent of contamination. See 56 FR 5600, February 11, 1991, or subsequent 

FR notices.]

For more information about the hazardous substances identified in this narrative summary, including general information regarding the effects of exposure to these 

substances on human health, please see the Agency for Toxic Substances and Disease Registry (ATSDR) ToxFAQs. ATSDR ToxFAQs can be found on the Internet 

at http://www.atsdr.csc.gov/toxfaqs/index.asp or by telephone at 1-888-42-ATSDR or 1-888-422-8737.