In a meeting last week billed as a chance for the public to ask questions about the rise in non-Hodgkin lymphoma (NHL) rates, comments were sparse from residents of the affected area. In a portion of Northeastern Mountain View, nearly twice the expected rate of the disease was found among residents between 1996-2005 in a recent study by the Greater Bay Area Cancer Registry, reported by the Voice and by NBC 11 Bay Area.
Instead, more time was spent by experts who argued that the rise in cancer was either statistically insignificant or had no connection to Trichloroethylene (TCE) contamination east of Whisman Road. The industrial solvent was dumped in the ground there by early computer component manufacturers including Fairchild Semiconductor and Intel and continues to be part of a lengthy cleanup effort.
In the presentation, part of the Moffett Field Restoration Advisory Board's Nov. 29 meeting, the Cancer registry's Kurt Snipes described it as "not a conventional true cancer cluster."
"Should residents be concerned about getting NHL if you lived in those areas?" Snipes said. "Based on our best assessments — not any more than anybody else in the area."
Snipes said the study looked at three cancers associated with TCE — kidney and liver cancer and NHL. Kidney and liver cancer rates in north-eastern Mountain View were average. The study compared the number of cancer cases in the area between 1988 and 2010 with rates in several local counties. Between 1996 and 2005 researchers expected to find 17 cases of NHL but instead found 31 cases of the cancer, which starts in the blood and spreads throughout the body.
The area studied is roughly east Shoreline Boulevard, north of Central Expressway and south of Highway 101.
"Why did this group of people in that time period get non-Hodgkin Lymphoma?" Snipes said. "It is very hard to say. When the numbers are very small, the statistics can bounce around wildly and it's difficult to pin down significance."
Whisman Road resident Jane Horton, one of the few to have found unsafe levels of TCE vapors in their homes, still suspects a connection, especially those who live on and around Walker Drive where an "air stripper" may have exposed residents to TCE vapors until 2003. The air stripper was used as part of cleanup efforts by pumping contaminated groundwater to the surface so that TCE could evaporate. She wonders why other cancers weren't studied, like lung cancer and brain cancer.
"I've thought about this a lot," Horton said. "For people who breathe the vapors, we don't have data that says breathing TCE vapors causes X kind of cancer. I don't believe there are studies that correlate that. There were 17 cases expected and it was 31. It was a spike. I don't know if these are people on Walker Drive. I don't know where they are.
The Cancer registry has declined to say exactly where the people lived in each case.
Testing of the outdoor air for TCE vapors around the air stripper was never done, though it was requested, said Lenny Siegel, director of Mountain View's Center for Public Environmental Oversight and a national expert on toxic cleanup.
"Some of us asked for sampling" before the air stripped was shut off, Siegel said. "It was not done."
"What we were told is based on contamination in the ground water the amount released into the air was not much higher than what you would find in the area," Siegel said. But he admitted that "we don't have good data, we just have a calculation."
Siegel argued that there was no real pathway for the TCE to have reached residents in the three census tracts studied.
"We know that there's no evidence people have been drinking contaminated water," Siegel said. "The EPA and responsible parties have done a great deal of indoor air testing" and found safe indoor air in homes near the plume except that of Horton's home, a home at Whisman Station over the GTE Superfund site and "some commercial buildings." Everywhere else, "we have pretty good evidence people were not exposed to TCE from the plume," Siegel said.
"It's because we've all been working to prevent that," Siegel said. "It is irresponsible of news media to suggest that it was otherwise."
Snipes said NHL can also be "caused by viruses, HIV and pesticides."