[CPEO-MEF] Companies promise to halt TCE releases in Mountain View

[Lenny Siegel <lsiegel@cpeo.org>]

Last night (February 18, 2003), at a Mountain View, California, City
Council study session, officials announced that the responsible parties
for the "MEW" Superfund Study Area had agreed to replace three
air-strippers with aqueous-phase carbon treatment units. These
electronics manufacturers, including a corporate descendant of Fairchild
Semiconductor, expect to spend a million dollars on the new equipment.
(MEW stands for Middlefield, Ellis, and Whisman, the three surface
streets that bound the study area, which officially encompasses three
properties on the Superfund National Priorities List.)

The three air strippers are designed to release volatile organic
compounds from groundwater that is pumped from a massive plume of
trichloroethylene and its daughter products. They have been particularly
controversial since the redevelopment of the property, where high-tech
software businesses such as Netscape and Nokia have replaced the pioneer
chipmakers of Silicon Valley. Looking like Disney's old Rocket to the
Moon ride, they stand out like sore thumbs on the modern high-tech
campuses. 

Because the air strippers were approved in the early 1980s, they have
not had to meet more recent standards for (hidden) visibility or off-gas
treatment. About two years ago, U.S. EPA explained that the units are
permitted to release contaminants at a level that met the Regional Ar
Quality Control Board's one-in-100,000 lifetime excess cancer goal.
However, based upon the concentrations in the water being run through
the strippers, EPA believed that actual releases are an order of
magnitude lower than those authorized in the permit.

Two decades ago, when EPA and the companies were designing the remedial
systems for this area, environmental activists argued that it didn't
make any sense to pump poisons out of the ground only to release them,
untreated, into the air. We were later successful in requiring off-gas
treatment at other water treatment units in the area, but these three
air strippers remained, as is, grandfathered in by the regulatory
system. As the property was redeveloped and the adjacent neighborhoods
gentrified, new employees and residents questioned the releases, with no
immediate success.

On January 22, 2003, EPA convened a public meeting to discuss the vapor
intrusion (indoor air) pathway at four Mountain View contamination
sites, including the MEW Study Area. EPA toxicologists explained that
Region 9 of EPA was using provisional Preliminary Remediation Goals for
TCE, based on the agency's continuing health assessment of the chemical.
Those new goals, which apply to air concentrations as well as water, are
significantly more stringent than the old standards, raising the
possibility that the permitted emissions may no longer be officially
"safe." Based upon existing data, EPA doubts that there is any acute
risk due to current exposures, but it has ordered new air sampling to
determine if concentrations are high enough to cause an unacceptable
increase in cancers in the long run.

Hundreds of people attended, and many expressed fear that they, their
co-workers, and families have been and continue to be exposed to unsafe
levels of TCE in the outdoor air. (Some of this fear was prompted by
news reports that long-term residents on one street adjacent to the MEW
Study Area reported a cluster of Parkinson's disease.)
They demanded that the off-gas from the air strippers be scrubbed.

In response, rather than add treatment devices to the air strippers, the
MEW companies are proposing to replace them with carbon filtration
systems that will directly extract the contaminants from the pumped
groundwater. They promise to install them as soon as EPA approves.

Local activists welcome the announcement. We expect to ask, however, who
will be exposed to the contamination when the carbon is regenerated elsewhere.

Meanwhile, EPA is moving ahead, in cooperation with the private
responsible parties, with plans to test indoor and outdoor air on and
near the MEW Study Area as well as the nearby residential complex built
on GTE's former property. That site is being addressed under the
Resource Conservation and Recovery Act (RCRA), not the Superfund law.

In my comments at the Council study session, I stressed the need to
develop a conceptual side model that considers all sources, all
pathways, and all receptors to determine whether air emissions from
contaminated groundwater pose a risk to the people who live and work in
my community.

Finally, environmental groups, the city government, EPA, and the MEW
responsible parties have all pledged to work together to establish a
community advisory group through which the people most affected will
have the opportunity to oversee the investigation of and response to
toxic air contamination in Mountain View.

Lenny
-- 


Lenny Siegel
Director, Center for Public Environmental Oversight
c/o PSC, 278-A Hope St., Mountain View, CA 94041
Voice: 650/961-8918 or 650/969-1545
Fax: 650/961-8918
<lsiegel@cpeo.org>
http://www.cpeo.org

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