TCE joins list of known carcinogens

Industrial solvent and degreaser was heavily used during the heyday of Silicon Valley's semiconductor industry

The prevalent groundwater toxin in areas around Palo Alto's Stanford Research Park and Mountain View's northern region received new recognition as a health hazard by federal officials. On Nov. 3, the U.S. Department of Health and Human Services announced it is adding trichloroethylene (TCE) to a list of known carcinogens in the department's biannual report on cancer-causing hazards.

The news comes as no big surprise. Federal health officials, for about 15 years, have warned that TCE could reasonably be linked to various forms of cancer. Since then about 20 epidemiological studies have shown a connection between TCE and various forms of cancer in mice, including kidney cancer and lymphoma, leading medical authorities to now reclassify it as a known carcinogen, said Dr. Linda Birnbaum, director of the National Institute of Environmental Health Sciences, which helps compile the carcinogen report.

"There's been concern about TCE and other solvents for a long time," Birnbaum said. "It takes a lot of analysis and a lot of review of the literature to compile this report."

The substance, an industrial solvent and degreaser, was heavily used on U.S. military bases and during the heyday of Silicon Valley's semiconductor industry. Tens of thousands of gallons of TCE were dumped into the ground and made their way into the groundwater in Santa Clara County before the chemical's hazards to public health were fully acknowledged.

Based on the new classification, a number of new regulations could be coming down the pipeline for TCE management, Birnbaum said. The White House is looking into further Environmental Protection Agency (EPA) limitations on TCE use in industrial degreasing and in dry-cleaning businesses. Data sheets for employee safety in handling toxic materials could also be updated, she said.

While the connection between TCE and cancer is now considered firm, the chemical's connection to other diseases remains less clear. Asked about a potential link between TCE and neurological degenerative diseases such as ALS, Birnbaum pointed to a 2014 study of the U.S. Marine Corps base Camp Lejeune in North Carolina, believed to have the largest TCE contamination in the country. The study tracked about 9,000 deaths at the base and found a higher hazard rate for ALS, but it was considered nonsignificant since it was based on small numbers, making it impossible to pin down separate effects, Birnbaum said. The link between TCE and various forms of cancer was far more evident.

TCE is among the most prevalent hazardous substances in the U.S., and it is found in at least 1,045 of the nation's Superfund sites, according to the Agency for Toxic Substances and Disease Registry. TCE is considered carcinogenic to humans by all routes of exposure, according to the EPA's 2011 health assessment report.

Related article:

Testing finds hazardous TCE under some College Terrace homes

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17 people like this
Posted by Campus Kid
a resident of Midtown
on Nov 12, 2016 at 9:09 am

Does anyone have a map of specific areas identified? I grew up on Stanford Campus ( very close) to College Terrace and on our short street there were many deaths due to cancer. A couple of us Camous kids have crossed paths as adults and independently mentioned this concern.

17 people like this
Posted by resident
a resident of Midtown
on Nov 12, 2016 at 9:40 am

Yes, please post a map of polluted properties.
Also post a list of which companies or property owners originated the pollution.
Thank you.

12 people like this
Posted by VS
a resident of Another Palo Alto neighborhood
on Nov 12, 2016 at 12:50 pm

VS is a registered user.

Why is the 2014 city water quality report, the most recent one that the city has available on line? Did the city stop transparency since then?

19 people like this
Posted by Marty
a resident of College Terrace
on Nov 12, 2016 at 4:27 pm

TCE as been found under the soccer fields Stanford built at the corner of El Camino and Page Mill, the staff housing Stanford Land Management is building next to College Terrace, and in the crawl spaces under a significant number of homes in College Terrace. Stanford will not take responsibility for this pollution. They claim the TCE detected under the homes in College Terrace is caused by homeowners storing white-board pens underneath their homes.

4 people like this
Posted by Bob Wenzlau
a resident of Crescent Park
on Nov 12, 2016 at 5:53 pm

WhatsDown is a mapping project we ( did in Palo Alto showing groundwater plumes. One can click on the plume and learn information. There are also numerous areas where land use will forever be restricted based on the occurrence of TCE and other chemicals. These areas are called institutional controls. We have been working to create a more structure approach to manage the legacy, as these residuals have persisted for nearly 50 years, and would reasonably persist for another 50 year. We had lots of support in this mapping by Palo Alto and Gunn High School interns. Use the chat tool if you have questions about the map or suggestions.

Web Link

5 people like this
Posted by Bob Wenzlau
a resident of Crescent Park
on Nov 12, 2016 at 5:57 pm

Actually, this WhatsDown link focuses a bit more on Palo Alto. In total we found about 12,000 parcels in the county impacted by shallow groundwater contamination, much containing TCE. Given the health issues, we have urged County Health and Supervisor Simitian's office to engage, but have met with reluctance. We can hope this coverage helps evolve the interest.

Web Link

9 people like this
Posted by TLM
a resident of Barron Park
on Nov 14, 2016 at 10:17 am

TLM is a registered user.

Here is a 2010 article from the Weekly that precisely describes contaminated areas under Stanford Research Park from TCE and other chemicals, as well as describing some of the decontamination procedures used in the past: Web Link

2 people like this
Posted by Brent Han
a resident of Gunn High School
on Nov 14, 2016 at 7:01 pm

The Gunn Investigative Medicine (I-MED) Club has been researching TCE for the past three years. We have collaborated with scientists and activists, including Mr. Wenzlau, to ascertain the challenges facing Palo Alto today. Our main concerns are vapor intrusion, plume expansion, and TCE permeating into the city's HDPE water pipes. The SF Regional Water Quality Control Board's 2015 Five-Year Review, for instance, claims that properties in the California-Olive-Emerson Plume with excessive subsurface TCE levels (above 0.48 ppb) are "safe." Yet it is only a matter of time before TCE and other volatile organic compounds accumulate at unsafe levels in the overlying spaces, where people live and work regularly.
We plan to release a news article and video concerning our research shortly. We also encourage readers to like our Facebook page, where we will coordinate with the public to take action.

Below are some useful links:

University Terrace Plume Map
Web Link

HP Superfund Site Plume Five-Year Review (Map on pp. 30-32; Vapor Intrusion Measurements on pp. 14-17)
Web Link

Gunn IMED Facebook Page
Web Link

8 people like this
Posted by Midtown Mom
a resident of Midtown
on Nov 14, 2016 at 10:34 pm

Hi! My house is not on top of the plume, but very very close to it (about 1.5 blocks.)
Two questions:

1) Is there a chance the plume will "move" or get bigger at this point?
2) What can we do to protect ourselves if our house is close to the plume? Should we test our indoor air quality?


6 people like this
Posted by resident
a resident of Midtown
on Nov 15, 2016 at 8:56 am

This is a Federally recognized problem now. Will Trump fix it or force HP to fix it or cover it up?

14 people like this
Posted by Just, Duh!
a resident of Another Palo Alto neighborhood
on Nov 15, 2016 at 12:22 pm

Those of us who lived in south SJ and were clients of Great Oaks Water Company in the 70's thru 90's already knew this!

2 people like this
Posted by Fred Balin
a resident of College Terrace
on Nov 15, 2016 at 12:33 pm

Fred Balin is a registered user.

Bob, Brent et al,

The Safety Element of the new Palo Alto Comprehensive Plan is on the agenda for a 5:30 pm meeting today (Tues., Nov. 15) of the Citizens Advisory Committee in Rinconada Library’s Embarcadero Room.

The draft section “Human-Caused Threats” can be found in Attachment D of the meeting materials at Web Link .

There appears to be just one program related to hazardous spills and plumes, known and unknown, in Palo Alto: "Policy S3.3: Continue working with appropriate agencies to clean up hazardous waste sites and contaminated groundwater."

I believe there is more that should be added. One item that comes to immediately to mind is the city taking responsibility for identifying and mandating state-of-the art mitigations when development occurs on or near hazardous materials sites. Palo Alto has every right to implement rules for buffer zones and building construction that go beyond those of the Department of Toxic Substances Control and the Region Water Quality Control Board.

Maybe you can come at 5:30 pm, speak then in oral communications, and add to the needs list.

11 people like this
Posted by Laughing
a resident of Community Center
on Nov 15, 2016 at 2:17 pm

Twenty years ago there were jokes about everyone from Menlo Park to San Jose drinking Chateau Trichloroethylene, another name for tap water!

2 people like this
Posted by Chip
a resident of Professorville
on Nov 16, 2016 at 2:37 pm

Back in the '70s, an industrial facility (maybe Fairchild?) was located slightly northwest of this area. I believe. There was a lot of discussion at the time of its closing about ground & groundwater contamination. If I recall correctly, the run-off from washing silicon chips was part of the cause.

Is this related in any way?

6 people like this
Posted by Toxic
a resident of Another Palo Alto neighborhood
on Nov 16, 2016 at 2:42 pm

For decades, TCE was used as a cleaning agent in several industries, and not just in Silicon Valley.

When I was growing up, a neighbor's daughter got a part-time job working at National Semiconductor in Sunnyvale, to help with college costs.

After five years of working as an assembler, this young lady developed a cough and a sickly color to her skin. After months of tests, it was determined that she had developed fatty liver disease as a result of TCE exposure in her work.

She improved somewhat after quitting that job at National Semiconductor, but was never truly well again for any length of time.

I was SHOCKED to see her obituary in the SF Chronicle last year: she had died of liver cancer after a long fight and unsuccessful wait for a liver donor!

I googled "fatty liver disease", and it seems it can turn into cirrhosis or liver cancer. A skinny 24-yr-old should NOT have fatty liver disease!

A non-smoking, non-drinking vegetarian should not have liver cancer! Even in her fifties.

7 people like this
Posted by Marty
a resident of College Terrace
on Nov 16, 2016 at 2:55 pm

Bob Wnnzlau said: "...Given the health issues, we have urged County Health and Supervisor Simitian's office to engage, but have met with reluctance..."

Why the reluctance from Simitian? I thought Democrats were supposed to care about pollution?

4 people like this
Posted by Brent Han
a resident of Gunn High School
on Dec 4, 2016 at 10:12 pm

Fred et al,

My friends and I would be happy to speak at Oral Communications come January. We've actually collaborated with City Staff in drafting a vapor intrusion policy like Mountain View's*, and can update the public then on our progress. Stay posted!

To Midtown Mom: Mr. Wenzlau's WhatsDown website is a superb mapping tool. You can also use the CA State Water Board's Geotracker website. Unlike WhatsDown, Geotracker doesn't show the extent of plumes (unless you click through technical reports.) TCE is said to smell like sweet cookie dough; I'm no expert, but if you are worried about contamination, I strongly urge you to test and encourage air flow (eg. open windows).

*See last 5 pages: Web Link

Geotracker: Web Link

Sorry, but further commenting on this topic has been closed.

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