Stoel Rives Summer Associate Carly Moran co-authored this post.

Ground Zero: The Silicon Valley

In an attempt to cleanup airborne toxins contaminating a large area of Mountain View, California’s North Bayshore neighborhood, the U.S. Environmental Protection Agency (“EPA”) has presented plans to update their existing cleanup strategy.  Specifically, the EPA plans to revamp their cleanup strategy for the Teledyne/Spectra Physics Superfund site, which extends  into the western side of North Bayshore.

The focus of the EPA’s concern is the pollutant, trichloroethylene (“TCE”), an industrial degreaser used in the area’s bygone semiconductor industry. For nearly thirty years, the companies responsible for the pollution have been tasked with treating the groundwater that contains traces of TCE.

In recent years, the EPA has expressed concern over the health risks associated with TCE if the toxin evaporates and becomes airborne. Since 2015, about 45 homes in Mountain View have been tested for traces of TCE.  Upon investigation, it was revealed that some of the tested homes had cracks in the foundation slabs which allowed contaminated vapors to leak inside the homes.  This raised a health concern, as these toxins are particularly harmful if they accumulate inside buildings where people spend prolonged periods of time.  Even short-term exposure to these toxins can pose a threat to pregnant women, particularly during their first trimester.

The New Cleanup Plan: The Future of TCE Vapor Intrusion Remediation

Although the EPA has been monitoring the vapor-intrusion of these TCE toxins for some time, it has not been formally integrated as part of the existing TCE cleanup plan. Under the new cleanup plan, vapor intrusion review would be formalized into the existing plan.  The updated plan would also emphasize bioremediation, a method in which fortified microbes are injected into the groundwater to break down hazardous compounds into harmless byproducts.  Past trials of bioremediation have proved to be effective, with the levels of TCE going from 300 parts-per-billion to four parts-per-billion.

According to EPA project manager, Angela Sandoval, the new cleanup plan can potentially reduce the cleanup time frame from hundreds of years to just decades as a result of these new cleanup remedies. With this new cleanup plan, the EPA hopes to see the levels of TCE in the North Bayshore area of Mountain View decrease.