Yakima Railroad

The Yakima Railroad Area is approximately six square miles in size and includes parts of the cities of Yakima and Union Gap. The Yakima Railroad Area has groundwater contaminated with Perchloroethylene (also known as tetrachloroethylene, PCE, or perc) from past industrial use, and is centered around the railroad/industrial corridor of the greater Yakima area.
 
PCE, a halogenated hydrocarbon, is a common solvent with many commercial and industrial uses. Commercial and Industrial operations in the Yakima Railroad Area that have potentially contributed to the PCE contamination of ground water include dry-cleaners, machine shops, activated carbon regeneration, pesticide formulators and historic operations that have yet to be identified.

The history of the Yakima Railroad Area begins in 1987. The Environmental Protection Agency (EPA) investigated sites in Yakima for potential Superfund candidates. PCE was found in the soil and the groundwater. The EPA referred its findings to the State of Washington.

In 1991, the Washington State Department of Ecology defined the potentially affected vicinity as the "Yakima Railroad Area". A selection of wells used for domestic water supply were sampled throughout the area; many wells scattered throughout the study area showed PCE contamination. Several of these wells were shown to have PCE contamination concentrations above 4 ppb, the cleanup level for PCE in groundwater.

Ecology initiated a bottled water program, providing free bottled water to residents in the area who were using groundwater as their primary source of drinking water. In February 1992, the Potentially Liable Parties (PLPs) were issued as enforcement order to take over the bottled water program. New PLPs have since been added to the enforcement order.

The PLPs requested that Ecology do a search for additional PLPs. A credible evidence report was submitted to Ecology. Based on this report, additional soil and water samples were taken.

In June 1992, a grant application was submitted by the cities of Yakima and Union Gap to connect about 1,200 homes in the Yakima Railroad Area to the cities' water systems. Ecology provided a 100% grant of $6.4 million to the cities. Construction began in 1993, and to date, more than 1200 homes have been connected to the Municipal water supplies.

The number of PLPs has changed over time. New PLPs have been discovered and added to the list. Several PLPs have reached a de minimus settlement with Ecology and exited the cleanup process. 

Twice a year, we collect groundwater samples in a 6-square-mile industrial area that parallels the railroad corridor in the cities of Yakima and Union Gap where concentrations of tetrachloroethene (PCE) continue to exceed the state Model Toxics Control Act (MTCA) cleanup level.

The primary purpose of this monitoring is to evaluate the effectiveness of these cleanup actions at reducing the contaminant concentrations in the groundwater. The data may also be used to identify areas of contamination that require further action. Groundwater samples will continue to be collected semi-annually to monitor PCE concentrations in the project area.