The Cupertino Courier
News
Contaminated area could be leaking poisons in groundwater
Cancer-causing chemicals are confirmed in Superfund site
By HUGH BIGGAR
Cupertino is home to one of the 23 Superfund sites in Santa Clara County--the highest number in a single county in the United States.
Nearby Sunnyvale has four Superfund sites, including two generated by Advanced Micro Devices.
At the moment, the city of Cupertino is planning to redevelop the area surrounding the Superfund site, known as North Vallco, and Apple Computer plans to build a second campus across the street. Since Superfund sites are regarded as risks to human health and the environment, the federal Environmental Protection Agency recommends both the city and Apple take proper precautions to ensure the area is safe.
"I hadn't heard about [the Superfund site]," said Marty Miller, chair of Cupertino's planning commission. At this time the city is in the process of redeveloping the mostly industrial North Vallco area, roughly bordered by Highway 280 Homestead Road, Wolfe Road and Tantau Avenue.
Miller said the Superfund property would have to be officially certified as safe and clear of contaminants for it to be developed. "Banks also wouldn't make a loan until the site has been cleared," he said.
The federal Environmental Protection Agency designated two properties at 10910 N. Tantau Ave. and 19000 Homestead Road as Superfund sites in 1982, due to the risks posed to human health and the environment. The Superfund sites are considered the EPA's national priorities, officially known as the National Priority List, for cleaning up toxic hazards.
"The NPL list is an environmental ranking process, with the primary driver being the threat to human health and the environment," said Penny McDaniel, a project manager with the EPA. In addition to the 23 Superfund sites in Santa Clara County, McDaniel said there are also thousands of NPL sites in the country.
In Cupertino, EPA found both Intersil and Siemens Corp. responsible for the city's Superfund site.
As a part of the two companies' work manufacturing semiconductors, both businesses contaminated soil
and groundwater from local spills and leaks from underground storage tanks, according to the EPA. Leaked or spilled chemicals included acids and highly toxic solvents such as chemical trichloroethylene, or TCE, on a site 1,500 feet from Calabasas Creek. Records show the toxins also leaked into groundwater used for the water supplies of the cities of Santa Clara, Sunnyvale and Cupertino. According to the EPA, at one point that water also fed wells within three miles used by 300,000 people. Five municipal wells used by the city of Santa Clara are also one mile from the site.
After the designation as a Superfund site, both businesses scoured the soil and groundwater, which, combined, measures about 15 acres. The cleansing efforts, costing more than $29 million, included removing and vaporizing soil, treating soil and groundwater and pumping out contaminated groundwater. The companies also removed underground storage tanks and have ceased operations at those sites.
Although some of the groundwater migrated off the site in the past, McDaniel said the groundwater is now contained and three contamination systems continue to operate.
"It takes a long time," she said of the cleansing, adding it could continue for 20 years.
"The site has a silty, clay soil," McDaniel said. "Contaminants adhere to that type of soil and flushing it out [of the groundwater] can take decades."
Even so, she said, health risks from exposure are under control.
"Pathways for exposure have been eliminated," McDaniel said.
Lavenia Millar, environmental programs manager for the city of Cupertino, said she was unaware of any completed cleanup work at the site.
"They are supposed to report back to us and we haven't heard from them in awhile," she said. The EPA is supposed to conduct five-year reviews of the site and the last one was scheduled in 2005.
McDaniel said the EPA and the San Francisco Bay Regional Water Quality Control Board will continue to monitor the site for potential hazards.
According to the EPA, such hazards, including the toxic chemical TCE, can cause cancer, leukemia, and respiratory and reproductive problems in humans through ingestion, contact or inhalation.
A 2003 study of TCE by EPA's scientific advisory board warned the chemical could be more harmful than originally thought. The board said the evaporated toxins could come up through the soil and into the atmosphere.
McDaniel said such reports are being closely watched.
"It has been determined that pathways of exposure are not a concern," she said of the Cupertino location. "However, science is always changing and if something comes up we go out and look at [a site] again."
Commissioner Miller said the effect of the Superfund designation on the future of the North Vallco area and possible impact on property values is difficult to determine.
"The city has an acute interest in making sure the site is safe before moving forward," he said. "[The Superfund designation] might make people very nervous."
Although Apple did not return calls for comment, McDaniel recommended it thoroughly investigate the land it plans to develop as a new $500 million campus at Tantau Road and Pruneridge Avenue. The campus is expected to house about 3,500 workers. "As far as we know, the groundwater hasn't migrated there," she said. "But it's close to an NPL site, so they should ensure they are not building on a site with toxic wastes. Due diligence is important and in their best interest."
