The level of toxics in the groundwater under a new Shea Homes development is low, by northeastern Mountain View standards. But at least one local couple has backed out of a purchase nonetheless, citing particular concern over TCE there.
The 150-unit row home development known as "Mondrian" at 505 E. Evelyn Ave. is currently under construction. Its three-bedroom homes are priced at around $600,000, and appeared to be a good deal to the Zimmermans, a young newlywed couple.
"Well-priced three-bedroom homes in Mountain View are hard to find," Elaine Zimmerman wrote in an e-mail.
The Zimmermans put down a deposit and were given a week to look through a 150-page binder full of information, fill out forms and gather the necessary records. At the last minute, they found a page in the binder mentioning the toxin known as trichloroethylene, or TCE. After some Google searching, the couple found a Web site describing TCE as highly carcinogenic, and decided the low-priced home wasn't worth the worry.
With comparably sized new homes in the area going for $900,000, "We decided that $300,000 is the price of your health," Elaine Zimmerman joked.
Don Hofer, vice president of Shea Homes Northern California division, says the Mondrian homes are not at all dangerous. But he added that potential buyers unhappy with that or any aspect of the homes shouldn't buy them.
"We have full Department of Toxic Substances Control approval of the site for housing and it's very safe," Hofer said. "In regards to homebuyers that canceled, that's why we disclose these things. If they aren't comfortable with the situation they probably made the right decision for all of us."
The City Council approved a rezoning of the area, from general industrial to medium density residential, in April 2006. That decision gave Shea Homes the green light to design the complex, which later received city approval.
Real or imagined
Numerous epidemiological and lab studies on the health effects of TCE are compiled in a 2006 report from the National Academy of Sciences National Research Council. Some studies indicate that TCE causes human fetus development problems and might cause congenital heart defects. Other studies say it may be linked with Parkinson's disease. Inhalation of TCE fumes also can have neurological effects, the report says, such as slowed reflexes. Various forms of cancer also were cited as possible side effects.
Though the groundwater concentrations are much lower than at other housing sites in the city, such as at Whisman Station, Elaine Zimmerman was still concerned.
"Is it worth freaking everybody out? I don't know," she said. She worries that others may not be as diligent as she was in reading all of the fine print. "I just think of all those other couples I saw" touring the homes.
Soil and groundwater contaminated with TCE are a common phenomenon in northeastern Mountain View. Just north of the Mondrian project is Whisman Station, a 503-unit development built on the site of a former GTE operation which used TCE as a solvent. After construction, 40 homes were tested in 2004 for toxic TCE vapors, which can come up through the soil and into the air above. One home was found to have unacceptable levels of TCE in the air -- a problem which could have been caused by a tear in the special membrane developers installed in the foundation during construction.
The leak was mitigated by installing a ventilation system. Other Whisman Station homeowners did not allow the EPA in their homes.
At Mondrian, the source of the TCE is likely a small building once located at the center of the site that was used to store "significant quantities" of hazardous materials for semiconductor wafer manufacturer Pacific Western, which occupied the site after 1979. The 1962 building's first tenants were Memorex and the Carburundum Company. Less toxic VOCs such as PCE and DCE were also found on the site, along with low levels of the pesticide DDT, evidence of the vineyard and orchard uses there before 1962.
Analysis of groundwater samples at the northwestern edge of the site showed no connection with the TCE plume at Whisman Station.
One way to determine the risk of vapor intrusion is by measuring groundwater concentrations. Maximum concentrations at Mondrian are 21 parts per billion, versus over 100 parts per billion at Whisman Station, says Mountain View resident Lenny Siegel, director of the Center for Public Environmental Oversight.
"Chances of a vapor intrusion problem at Mondrian are probably lower than Whisman Station, but they can't be dismissed without more data or mitigation and follow-up sampling." Siegel said in an e-mail.
But Hofer says Shea Homes will not have the indoor air tested in the homes after construction. A sealing layer under the cement slab foundations, or "sub-slab membrane," is already being used at a "substantial cost," to prevent vapor intrusion, Hofer said, even though levels were not high enough for it to be a requirement.
The Department of Toxic Substances Control, which usually is in charge of air quality at a site, has classified 505 E. Evelyn Ave. as "no further action required," after a "voluntary cleanup agreement" was completed in 2006.
This was troubling to Siegel, who pointed out that the 21 parts per billion of TCE found in the groundwater at Mondrian is four times higher then the remediation goal the EPA is using at other Mountain View sites, such as Moffett Field, where 5 parts per billion is the goal of a major TCE plume cleanup.
After contacting a dizzying array of agencies, including the EPA, the state Department of Toxic Substances Control and the Regional Water Quality Control Board, the Voice was unable to determine if any government agency was working to clean up the site's groundwater. A spokesperson from Toxic Substances Control referred the Voice to Nathan King, the water board's project manager for a nearby site at 303 Ravendale Ave. King could not be reached by press time.
* An environmental impact report for 505 E. Evelyn Ave. can be downloaded from the city's Web site; a discussion of toxics begins on page 80
* The Academy of Science's TCE human health report summary is available here