Palo Alto normally is not considered at risk from toxic materials, but there are areas of contaminated groundwater and soil due to operations in the Stanford Research Park, plus spills of toxic materials in the Research Park from CPI occurred near homes. The most serious groundwater and soil contamination is by the HP Superfund sites at 1501and 640 Page Mill Rd.
Contamination from the 1501 site is local and remains on site. Contamination from 640 Page Mill and a Varian site at 601 California Ave. extends across El Camino into the California-Olive-Emerson (COE) area. It is being cleaned up but the pump-and-treat system seems to have reduced aquifer contamination about as low as pumping can accomplish. Addressing problems from toxics in the plating facility at CPI also is a serious issue.
The solvent of most concern is trichloroethene (TCE), a known carcinogen likely to cause Parkinson’s disease, liver and kidney damage. Recently it was identified as causing birth defects after exposures at levels as low as 2.1 micrograms/cubic meter.
TCE has been known to be toxic for over 100 years as a drinking water contaminant. Toxicity from breathing TCE vapors which entered occupied buildings from contaminated soil and groundwater was recognized as a serious problem in 1998.
Breathing TCE is worse than drinking contaminated water because it’s more easily absorbed into the body through the lungs. Vapor intrusion at levels above 3 micrograms/cubic meter in commercial buildings or 0.5 micrograms/cubic meter in residential buildings puts occupants at risk of serious health problems such as cancer.
Vapor levels beneath a building’s foundation can be more than 100 times greater than levels in nearby soil, as the foundation can trap vapors allowing them to concentrate. Vapor barriers, sub-slab ventilation and regular indoor air monitoring have become standard practice to prevent vapor intrusion of harmful levels of TCE into occupied buildings.
Unfortunately the Regional Water Quality Control Board (Water Board) which has oversight of our COE area doesn’t require vapor barriers and sub-slab ventilation under new construction, putting future occupants of those sites at unnecessary risk.
CPI which took over an old Varian building operates plating facilities that have had three spills and releases of toxic chemicals near Barron Park residences since 2006. Until last month the quantities of nitric acid and potassium cyanide were far above allowed limits under State regulations.
CPI claimed they needed thesequantities to operate effectively. Now they say they can operate fine with smaller quantities under the maximum allowed by the State. Neighbors want the plating area moved at least 300 feet from residential properties, but CPI says they can’t do that and remain competitive.
Of course there are other plating facilities within 20 miles of CPI that could do the work, but CPI ignores that. An alternative is to require plating operations to be removed after a 14 year amortization period, but that will continue to expose residents and people at Barron Park School to any future toxic spills. These hazards must be addressed and resolved now, not in 2026.