Despite political pressures to kill it, a long-delayed Environmental Protection Agency report has finally been released confirming the toxicity of the industrial solvent that has contaminated groundwater at a central Palo Alto Superfund site as well as in Mountain View.
The EPA's Final Health Assessment for trichloroethylene (TCE) characterizes the solvent, which was detected at the "Hewlett-Packard 620-640 Page Mill Road Superfund Site," as "carcinogenic to humans by all routes of exposure" and says that inhalation can cause "hepatic, renal, neurological, immunological, reproductive, and developmental effects."
Locals in Mountain View have paid particular attention to the EPA's findings on TCE, which was dumped into the ground by computer component manufacturers near North Whisman Road in the 1970s.
A link long has been suspected between TCE exposure and a cluster of seniors with Parkinson's disease and brain tumors on and around Walker Drive near Whisman Road. The Mountain View Voice reported in 2002 that six residents were found with Parkinson's on Walker Drive and four others were found nearby who had had brain tumors. They had all lived for decades next to an area that may have provided a steady supply of TCE vapors -- vapors that continue to be measurable in the outdoor air.
Activist and Whisman Road resident Jane Horton said the report's release was a small victory for the Walker Drive residents and many others who have been exposed to TCE nationwide.
"We can now say, 'Yes, this is a bad chemical and yes, it is proven,'" said Horton. "The fact this even happened, especially in this political climate, is a cause for celebration."
Some suspect that an air stripper used for years to treat TCE contaminated groundwater on the east side of Whisman Road near Walker Drive was partly to blame for the cases of Parkinson's, a degenerative disease affecting the central nervous system. Like a smokestack, the air stripper vented TCE to the atmosphere as contaminated groundwater was pumped to the surface.
"Everyone seems to think that there is something strange about this, everyone is concerned, especially the people who have Parkinson's," said resident Lori Hand in 2002. Hand said three had died and two others were in their 70s at the time. She said they had all lived there for over 40 years.
No evidence was found to make a link with the Parkinson's cluster. The air was never tested inside the homes of those with Parkinson's and Horton said the outdoor air wasn't tested until the air stripper was replaced with special filters that contained the vapors.
It was suspected that the TCE vapors, which have a half life of several days, were blowing into people's homes. "It's when it gets trapped in your home that it becomes a problem," Horton said.
Horton has some experience with that problem. Her Whisman Road home, which she purchased in 1975, was the only one in the area found to contain unacceptable levels of TCE vapors. The vapors were entering her basement from the large contaminated groundwater plume that computer component manufacturers left behind. A ventilation system now runs at all hours to keep the vapors out of the house, even in power outages, and her air is tested twice a year.
TCE vapors can still be measured in the outdoor air. Lenny Siegel, director of the Center for Public Environmental Oversight, said it was at 0.2 micrograms per cubic meter last time he checked, which is well below EPA's standards for indoor air. It wasn't uncommon for it to be well over 1 microgram per cubic meter at such sites when TCE was in use, which is above current standards for indoor air.
The EPA says 761 superfund sites are contaminated with TCE nationwide. People have died "horrible deaths" from their exposure to TCE in other places, Horton said. When she testified about TCE to the National Academy of Sciences, Horton recalled several "heartbreaking stories", including one form a brother and sister who carried their father's ashes. He was one of many workers of a Mattel toy factory in Oregon who died after exposure to high levels of TCE.
"This has really been long and lonely battle for individuals all throughout the country," Horton said.
The EPA's final health assessment for TCE is expected to accelerate cleanup efforts and make cleanup standards for indoor air and drinking water more stringent, especially in other states. By all accounts, the EPA's local cleanup standards are already relatively stringent and may not change much. But local activists say they are still frustrated by the slow pace of cleanup in the Whisman Road area.