A Google spokesperson said employees have been notified and an internal website has been set up with information on TCE and indoor air testing results.
TCE (trichloroethylene) has contaminated groundwater in the area and was recently found evaporating into Google's offices at 369 and 379 Whisman Road at levels above EPA limits.
TCE is known to cause cancer, among other health problems, including heart defects in children born to mothers who were exposed during critical stages of heart development, the EPA says.
The occupants of two homes on Evandale Avenue also have a cause for concern after the Environmental Protection Agency recently reported that their homes had elevated levels of TCE in the indoor air. The homes, exact addresses withheld, now have ventilation systems running at all hours to keep the vapors at bay.
Short-term exposure risks
Siegel raised the concern about short-term exposure after a local EPA official said last week that TCE's potential health concern comes from long-term exposure and a Google spokesperson told the Voice "The health of our Googlers was not put at risk in any way at any time."
Despite news reports to the contrary last weekend, a Google spokesperson said on Feb. 25 that Google has not evacuated the pair of buildings at 369 and 379 North Whisman Road, where over 1,000 employees have been housed since July.
TCE was left as groundwater pollution under the buildings by early chip manufacturers Fairchild, Raytheon and Intel, among others. The chemical was still found evaporating into the buildings built in 2003 despite decades of cleanup efforts, and ventilation systems that run around the clock to push out the vapors.
Despite Google's assurances that employees were notified, last Wednesday, an employee of the kitchen at 369 North Whisman Road said she did not know anything about the issue, but noted that she had seen several pregnant employees in the building.
Two other employees who were visiting the cafe at 369 Whisman Road from other Google buildings declined to comment, but one had not heard of an issue with TCE.
A company spokesperson declined to say who exactly at Google was notified. "We aren't going to get into the specifics of every internal action. We are incredibly transparent about this stuff, have a site up internally for anyone to view, held talks for interested Googlers, met one-on-one with those who had specific questions, and have continued to communicate to Googlers," the Google spokesperson said.
Risk to pregnant women
The level of vapors that employees in the Google buildings were exposed to, according to air samples taken in late December, were as high as 7.8 micrograms per cubic meter of air at 379 Whisman, indicating a potential risk to pregnant women, Siegel said.
The amount of TCE vapor that could trigger heart defects in unborn children is 2 micrograms per cubic meter when exposed at all hours of the day, 24 hours a day, seven days week, according to the EPA's Final Health Assessment for TCE, issued in 2011, Siegel notes. For 40 hour-a-week workplace environment, EPA officials in the Pacific Northwest say that 8.4 micrograms per cubic meter is a comparable number.
"The levels in these two buildings approach that number," Siegel told the Voice. "Considering that many women work 50 or 60 hours per week in a typical high-tech company, and that measured levels vary significantly over time, there is cause for concern."
It isn't clear how long TCE exposure takes to to cause birth defects, though there is a focus in EPA documents on a three-week period when major milestones of heart development occur in a fetus.
"Nobody knows for sure, whether it's one day exposure or three weeks (of exposure) that will cause cardiac birth defects," Siegel said. "The science hasn't been done."
"I want to know what Google employees were told, if anything, about the investigation," Siegel said. "Employees have a right to know and respond to elevated levels of TCE in their workplace."
In a review of decades of TCE research published in December, scientists concluded that there is "strong evidence" from various kinds of studies that TCE causes "fetal cardiac malformations."
The paper is titled "Human Health Effects of Trichloroethylene: Key Findings and Scientific Issues" and was written by a team of scientists lead by Dr. Weihsueh A. Chiu, the EPA's chemical manager for TCE.
"TCE is carcinogenic to humans by all routes of exposure and poses a potential human health hazard for non-cancer toxicity to the central nervous system, kidney, liver, immune system, male reproductive system, and the developing embryo/fetus," the paper says.
As far as cancer goes, the paper says the strongest evidence links TCE and kidney and liver cancers, as well as non-Hodgkin lymphoma, which had a spike in rates between 1996 and 2005 in the area around the plume, according to a Bay Area Cancer Registry report released last year.
The report comes as various EPA regions set different indoor air limits for TCE vapors in advance of a level expected to be set by EPA headquarters.
TCE limits exceeded
The EPA is uncertain as to how long Google employees may have been exposed, but it may have been five weeks or more, according to air sampling results obtained by the Voice.
In the fourth week of November, results were not a cause for alarm. Levels in the two Google buildings were below the limit of five micrograms per cubic meter as long as ventilation systems were on. But on Dec. 28 at 369 Whisman Road, levels around several offices and conference rooms were found above the limit with ventilation on, the highest being 6.4 micrograms per cubic meter. At 379 N. Whisman Road, levels were above the limit at one of six test stations, where it was recorded at 7.8 micrograms per cubic meter.
There was apparently a fix soon after. In the fourth week of January, tests found only trace amounts of TCE vapors in both both buildings with ventilation on. Sampling in 2010 and 2003 also found relatively low amounts.
Pregnant women would be particularly at risk if the ventilation systems were to fail or in case of a power outage. With ventilation systems off on Jan. 1, sampling results show concentrations well above the 5 micrograms per cubic meter limit at all of the workplace test stations at 379 Whisman, with levels as high as 120 micrograms per cubic meter. At 369 Whisman, limits were exceeded at four of five of test stations in the workplace, with levels as high as 30 micrograms per cubic meter with no ventilation.
"TCE is a hazardous substance with the potential to cause health effects," said EPA spokesperson David Yogi in an email. "EPA's indoor air cleanup levels are protective of short-term and long-term health concerns."
He said that when the EPA became aware that indoor air levels at commercial and residential buildings in the area exceeded its benchmarks, agency officials took immediate action to lower the contaminant levels.
To better protect workers in the future, the EPA reports that "sub-slab depressurization systems" are being planned to draw the vapors away before they can rise into the buildings.
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