An approved project to build 26 homes at 277 Fairchild Drive is being delayed by officials with the U.S. Environmental Protection Agency after they discovered the site's soil exceeded safety levels for trichloroethylene (TCE).
Representatives for the developer, Warmington Fairchild Associates LLC, say they will clean up the soil contamination over the coming months before proceeding with construction.
Dozens of samples taken last year at the property showed TCE levels that exceeded the EPA's safety levels. The agency defines unsafe TCE levels as exceeding 20,000 micrograms per cubic meter. Samples from the site had levels as high as 410,000 micrograms per cubic meter.
Before the TCE levels were known, Mountain View city officials had approved plans in 2015 for the Fairchild Drive property to be redeveloped into 22 rowhouses and four single-family homes. Previously, the site was an RV park and motel that was rented out as permanent housing.
In a settlement reached with the EPA earlier this summer, Warmington officials agreed to clean up the hazardous vapors in the top layers of soil. In addition, they will inject "bioremediation" chemicals into the aquifers below, which will help break down the TCE contaminating the groundwater.
EPA officials have classified TCE as a carcinogen by any route of chronic exposure. Mountain View's contaminated ground water plumes, in many places a legacy of the semiconductor industry, can result in exposure to TCE vapors, especially in poorly ventilated buildings. TCE is known to cause cancer and other health problems, including heart defects in children born to mothers who were exposed during critical stages of heart development, according to the EPA.
Warmington bears no responsibility for causing the contamination but agreed to help clean up the site in order to avoid prolonged delays for their development. The presence of TCE at the site is linked to the semiconductor firms Fairchild Semiconductor, Intel and Raytheon that previously operated industrial plants nearby. In recent years, the contaminated groundwater plume known as the Middlefield-Ellis-Whisman Superfund migrated into the Evandale neighborhood.
Warmington project manager David Agee said he expected the cleanup to take about six months. If all goes according to plan, construction on the homes could begin next spring, he said.