Source Area and Environmental concerns
near 800 block of S. Lincoln Ave.

In October 2002, Colorado Department of Transportation (CDOT) workers on the Cherokee property discovered trichloroethylene (TCE) in high concentrations.

Prior to Cherokee purchasing the property from Gates Rubber Company, Cherokee conducted monitoring that detected TCE in groundwater, but not at the concentrations or the specific location later discovered by CDOT.

Within a week after the CDOT discovery, Cherokee began drilling monitoring wells in an effort to determine the extent of the TCE discovery and also began source area remedial actions. As of April 2004, Cherokee has installed 88 monitoring wells, all focused on determining the extent of TCE migration from the initial CDOT discovery.

Through these efforts, Cherokee has found TCE concentrations in groundwater along the 800 block of South Lincoln Street that caused initial concern over the indoor air quality for the nine homes along the 800 block of South Lincoln Street. Since the groundwater is not used as drinking water, the only way residents can be exposed to TCE is from the possibility of TCE volatilizing (vaporizing) from groundwater, through soil, and into homes impacting indoor air quality. (Read more about vapor intrusion)

Due to Cherokee's dedication in protecting human health, Cherokee sampled the indoor air quality at eight of the nine homes nearest the high groundwater TCE concentrations. These homes were tested for a second time in early 2005.

The indoor air sampling found concentrations of TCE far below the CDPHE health-based guideline and below national average background air concentrations. These results strongly support the finding that TCE from the former Gates property does not pose a risk to human health via indoor air.

In addition, sampling has determined that groundwater TCE concentrations above the CDPHE Action Level on and off the Cherokee property are limited to a localized area. CDPHE's groundwater Action Level is based on a groundwater concentration that protects residents from the only possible means by which residents could be exposed to TCE – indoor air.

The combination of these findings is extremely encouraging because no residents in the vicinity of the former Gates Rubber Company have a health risk associated with TCE.

Meanwhile, Cherokee is conducting activities at the source area to minimize the extent of the TCE plume. An anaerobic molasses solution is being regularly injected into wells along I-25 near the 800 block of South Lincoln that essentially causes bugs in the soil to eat the molasses and break down the TCE. This work has substantially decreased the size of the TCE plume.

Additionally, a soil vapor extraction system has been installed directly at the source that is pumping out pure TCE product. This work at the source area is on-going to ensure that the TCE stops its off-site migration.