Publication Date: Friday, October 04, 2002
EPA questions safety of Mountain View air
EPA questions safety of Mountain View air
(October 04, 2002)
More than a decade after they deemed it safe, officials say air in the Middlefield-Ellis-Whisman area needs more testing
By Faiza Hasan
More than a decade after claiming that Mountain View residents are safe from toxic chemicals in the city's groundwater, the U.S. Environmental Protection Agency now says it is unsure of whether chemicals escaping into the air are dangerous.
This step was prompted by recent research showing that Trichloroethene (TCE) -- which was leached into the city's groundwater by computer chip companies in the 1970s -- is 60 to 70 times more toxic than was previously thought.
The EPA is concerned that the TCE in the area known as the Middlefield- Ellis- Whisman Superfund site is now escaping into the air in the office buildings.
"TCE is persistent in the environment and it migrates easily," said EPA Toxicologist Stan Smucker.
"We are looking at chemicals escaping and entering the building, we are concerned that they might be inside the building," said Alana Lee, EPA project manager for the MEW site.
She said that the EPA will only require the polluting companies -- which include Intel, Raytheon, Fairchild and other -- to test those buildings which were former plant sites and which are now occupied by the semiconductor manufacturers to undergo testing. "We think (the tests) will be representative and based on those results will determine the potential risk to other residents," she said.
The companies will be required to conduct indoor, outdoor and possibly even soil tests. The data collected will determine the extent of exposure and the risks involved.
"Over seven to eight years the EPA's national center for environment assessment has been updating TCE health assessment; it was a long time coming," said Smucker. "TCE is one of the most common contaminant at the Superfund sites."
Surprisingly, when the original risk assessments for the MEW Superfund sites was done in the 1980s, the EPA did not even consider looking at the pathway TCE can take the groundwater into the air.
"When we initially evaluated the path, we did not look at the groundwater," explained Lee. "That was ten years ago."
"We know lot more today, there are more studies, more information," she said.
Another reason for the recent EPA decision is the fact that the five year review for the Superfund sites is coming up soon. The EPA feels that it would be a good opportunity to fill in the gaps in information and look at amounts of chemicals in the groundwater to see if they have changed.
The EPA will also study the emissions of TCE from air strippers, slender towers into which TCE-tainted groundwater is pumped and the TCE is allowed to evaporate, unfiltered into the surrounding air.
The strippers are used to remove contaminants from the old Fairchild chip factory. As the Voice reported in 2001, these air strippers are allowed to emit one pound per day of TCE. But some -- including one on the Netscape campus on Whisman Road -- were constructed under old regulations; because of a grandfather clause, they are permitted to release 24 pounds per day of the toxin.
"The Fairchild air stripper pumps out contaminated groundwater and emits low levels of chemicals from its stacks. We are asking Fairchild to re-evaluate those emissions with the new toxicity values by this week. It is part of our five year review," said Lee.
"The EPA is involved in toxicological studies that say that TCE is more toxic," said Lenny Siegel a Mountain View resident and head of the Center for Public Environmental Oversight. "There is a growing recognition that the earlier models (for detecting) indoor air exposure don't always work, that they are used not necessarily going to be accurate."
Environmental advocates praised the policy change.
"I'm pleased to learn that EPA is finally starting to pay attention to something we've been trying to change for years," said Ted Smith, executive director of the Silicon Valley Toxics Coalition, an environmental watchdog group. Smith has been advocating for EPA to test indoor air for the past decade.
Siegel also said that the EPA reassessment is a positive step. "This is something, once we see all the explanations, it may have significant national results," said Siegel. "It might result in a new policy and cause huge samplings to be done around the country."
Lee said that part of the reason EPA wants the companies to conduct the research is to find out more about the health risks. "We want to find out whether there is a potential risk to human health from indoor air contamination," explained Lee. It is generally believed it would take a lifetime of exposure to small amounts for any serious health problems to develop.
"It depends upon how much people have been exposed and for how long," said Siegel. "We are not talking about lethal doses, but exposure over a period of time increases the chances of serious diseases."
The serious risks include cancer and, according to Smucker, research shows that children are more susceptible to TCE as the toxin isn't cleared quickly from their bodies. He believes that there is no reason for panic, and asserted that the TCE concentration in the groundwater is not high enough for health risks.
Siegel agreed that people working at those buildings should not worry, for the TCE health risks are the same as those posed by other environmental problems. "I don't think people should panic," he said.