EPA seeks to remove Mountain View site from Superfund list, despite lingering chemical plume

A Mountain View property once brimming with toxic contaminants is now officially being pulled from the U.S. Environmental Protection Agency’s list of superfund sites, shortly before apartments are built there. It signals the end of a decadeslong cleanup operation, even though a chemical considered likely to cause cancer is still present on the site.

The site at 1710 Villa Street was previously home to the Jasco Chemical Corporation before it was designated as a Superfund site in 1989, becoming one of seven places in Mountain View where harmful chemicals have been discovered in the underlying soil and groundwater.

The process for removing Superfund sites, a formality known as “delisting,” is being pursued in record numbers under the Trump administration, though the cleanup work itself often has taken place years prior. The action to remove Jasco from the federal register comes despite the high levels of tetrachloroethene (PCE) in the groundwater, requiring that special measures continue to be taken at the site.

“At this point all response activities are complete, and the criteria for deleting the site from the national priorities list has been met,” said EPA project manager Eric Canteenwala at the April 28 Mountain View City Council meeting. “We’re kind of at the point where no further response is needed.”

Between 1976 and 1995, Jasco used the location for formulating and repackaging chemical products for sale, handling solvents in bulk and storing chemicals in eight underground storage tanks that have since been removed. Due to either poor waste disposal practices or leaking tanks, the site was found to be rife with nine harmful compounds, including PCE (also known as perchloroethylene or perc), benzene, vinyl chloride, methylene chloride and trichloroethene (TCE), which is known to cause cancer.

In the years that followed, the former industrial site was stripped down and excavated, with construction crews removing about 572 cubic yards of soil and backfilling it with concrete. Today, the excavated areas remain solid concrete down to 28 feet deep. Storage tanks were also removed during the cleanup, and groundwater was pumped to the surface and treated, Canteenwala said.

The Jasco property, a square-shaped patch of the Shoreline West neighborhood, is undeveloped, standing in stark contrast to the neighboring apartments and single-family home. And after years of monitoring the site, the EPA announced in 2014 that the cleanup was a success and the site was ready for commercial and residential uses.

And development is coming soon. In June 2019, the Mountain View City Council approved a project that would put a 226-unit apartment complex on the Jasco site and adjacent properties that includes two levels of underground parking. Though the project was approved, environmental documents for the proposal disclose a twofold problem: contamination is still present on the site, and construction activities could put nearby residents at risk.

PCE, a chemical used in dry cleaning and for degreasing metal that is classified by the EPA as a likely carcinogen, is still being detected in the site’s groundwater, though it is being attributed to an “off-site” source and therefore not a part of the EPA’s cleanup evaluation. Oversight of the contamination was passed off to state officials at the California Department of Toxic Substances Control, which has been unable to identify who is responsible for the PCE plume.

The project proposes placing a “vapor barrier” underneath structures to prevent PCE vapors from affecting residents living in the future apartment complex, as well as mitigation measures to ensure construction doesn’t spread contamination. The property is still subject to an environmental covenant overseen by the state, requiring the property owners to comply with vapor intrusion requirements, post-construction monitoring and soil management.

The EPA is scheduled to put out a notice of intent to remove Jasco as a Superfund site on May 11, soliciting questions and comments over 30 days.

For the EPA, delisting can be seen as a superficial act that happens long after remediation, similar to the Jasco site cleanup that was finished in 2002. But lately it has transformed into a priority, with the Trump administration touting a 13-year high in removing Superfund sites from the national priorities list as of 2018.

“This remarkable accomplishment is proof that cleaning up contaminated lands and returning them to safe and productive use is a top priority of the Trump EPA,” said Andrew Wheeler, then the acting EPA administrator.

Paradoxically, the Trump administration has also sought to slash funding to the federal agency each year by as much as 31%, and the backlog of unfunded superfund projects has grown as of 2019 to the largest in more than a decade.