College Terrace residents to test homes for TCE contamination

State toxic substances agency affirms Stanford mitigation plan and that neighborhood is safe

Dissatisfied with a state agency's assurances that hazardous chemical vapors from a former Stanford Research Park industrial site on California Avenue pose no risk to nearby residences, College Terrace neighbors plan to hire a consultant to monitor the indoor air-quality of their homes, they said.

The decision to move forward with their own consultant came after the state Department of Toxic Substances Control (DTSC) concluded that Stanford University's plan to mitigate the impact of toxins discovered on its property at 1601 California Ave. is sufficient and no additional testing at the site or adjacent properties is necessary.

Elevated contaminants in the soil were detected in one area — the vicinity of a former plating solution sump and operational areas of a former manufacturing facility — but the vapors from the chemical do not pose a threat to residents in nearby College Terrace, the agency concluded.

The university, which is building 180 homes for junior faculty on the property, plans to move a number of residences from the most contaminated "hot spots" to another location on the property as part of its mitigation plan. It also proposes to cap some of the contaminated areas with roads and add vapor barriers to new homes to prevent fumes from seeping in.

The site has been thoroughly evaluated; the extent of soil vapor is defined; the development plan protects human health; and an international expert on vapor intrusion concurs with Stanford's findings and approach to address the vapor problem, according to the agency.

The agency approved the Revised Supplemental Investigation and Risk Assessment Report on April 4, according to a letter supplied by Stanford.

For College Terrace residents who live just across California Avenue, concerns remain high that hazardous trichloroethylene (TCE) vapors found in the University Terrace construction site in November 2015 may still pose a risk to their neighborhood.

TCE is a solvent used mainly to remove grease from metal parts but also is an ingredient in adhesives, paint removers and other products. It breaks down slowly in soil and water and is known to cause some cancers, according to the U.S. Environmental Protection Agency (EPA).

But the university's consultant Haley & Aldrich, Inc., found the levels are below maximum levels allowable for residential sites, a finding that is in line with EPA guidelines, which are also accepted by the state DTSC, officials noted in their report.

College Terrace resident Fred Balin, who has been following the developments, said when TCE vapor becomes trapped in an enclosed space, it can concentrate and become a health hazard. The issue for College Terrace is that residents remain vulnerable because their homes do not have vapor barriers and other safeguards planned for the new construction, he said.

In January, a College Terrace Residents' Association subcommittee studying the site asked the DTSC to review Stanford's findings and require the university to remove the contaminated soil, conduct additional monitoring along their neighborhood's border, and take additional safety measures to prevent TCE from potentially migrating into the soil under their homes.

The subcommittee, which includes a research chemist, a NASA environmental scientist and a toxic-vapor-control expert, outlined nine major concerns and concluded that the consultant's report showed the TCE vapor has the ability to migrate through the soil. Subterranean water channels might transport the chemical vapors to their neighborhood, where it could enter their unprotected homes. The residents' position was supported by the Center for Public Environmental Oversight, a Mountain View-based watchdog group.

After reviewing Stanford's proposal, DTSC concluded that the university's plan for the development of University Terrace is adequately protective. In addition to moving some homes off of the contaminated area, and it will add compacted clean soil to a height of 15 feet, add 10-inch-thick concrete slabs that are resistant to cracking, and install vapor barriers and other measures to prevent vapor leakage. Homes will have a restrictions covenant that prevents digging up the foundation for future construction, DTSC noted.

DTSC also concluded that Stanford had remediated the site by removing the source of TCE when it removed the former plating solution sump in March 2015. Building demolition of 1601 California in March and April 2015 also included removal of all chemical-storage areas, piping, sewage and storm drain lines. The site did not reveal concentrations of TCE in the soil that would warrant deep excavation, the agency noted.

DTSC said that there was also no proof that the TCE soil vapor had migrated. It maintains that the soil vapor remains in defined areas.

The College Terrace subcommittee disagrees with this finding. Data it extrapolated from Haley & Aldrich's report shows the chemical vapor had migrated 300 feet and contaminated part of another site, at 1501 California Ave., which is also part of the development, said Ed Schmitt, research chemist and association subcommittee member who investigated the data.

DTSC wrote that TCE was not detected in soil vapor collected at nearby sampling at 1501 California at concentrations exceeding the DTSC screening level.

According to Lenny Siegel from the Center for Public Environmental Oversight, TCE was found in soil vapor at a depth of 25 feet at 1501 California, about 300 feet down-gradient from the former sump. DTSC had also previously attributed the presence of TCE vapor at 1501 California to the 1601 California sump release, he noted. Siegel said he supports installing venting technologies for the homes rather than barriers.

"Since TCE has moved 300 feet, either in aqueous or gaseous form, to the next property, I don't see how Stanford and DTSC can conclude that vapors cannot move 50 feet into homes," he wrote in response to DTSC's findings.

DTSC noted that TCE was detected in shallow groundwater beneath the 1601 California site, but the concentrations are limited in extent and below environmental screening levels for groundwater, and they would not contribute to vapor intrusion.

Out of nine groundwater samples taken by consultants, low TCE concentrations were found in two, at 45 and 13 micrograms per liter respectively, the agency wrote. Boring samples down to a depth of 68 feet did not show continuous migratory channels that would serve as potential pathways for the TCE-vapor contamination, DTSC wrote.

The spread of soil vapor also is not likely because the primarily fine-grained, clayey soil along California Avenue inhibits its migration, DTSC concluded.

"The sampling pattern and analysis demonstrate that TCE in soil vapor remains within the site. There are 15 soil-vapor sampling locations parallel to California Avenue and opposite the College Terrace community in which analytical results show that TCE either was not detected or detected below the DTSC residential screening level. These results lead to the conclusion that TCE-impacted soil vapor does not extend off site to S. California Ave.," DTSC wrote.

Siegel maintains there isn't enough data to justify assumptions about soil lithology or the direction and magnitude of TCE migration.

"Based on prevailing groundwater flows, I agree that vapor exposures in College Terrace are not likely, but I don't believe that enough groundwater or vapor sampling has been done to rule it out," he wrote.

Related content:

VIDEO: College Terrace resident Fred Balin joins Weekly Editor-in-Chief Jocelyn Dong and reporter Sue Dremann to discuss the underground toxins at Stanford Research Park

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27 people like this
Posted by Trust but verify
a resident of Evergreen Park
on Apr 12, 2016 at 11:27 am

I thank Fred Balin for driving the effort to look into this potential contamination and mitigation.

This type of issue is too important to merely accept the word of a party (i.e., Stanford) who clearly has a conflict of interest in the matter, and who would (naturally) want the issue to go away.

Not saying there is necessarily a problem, but we shouldn't be hand-wavy about it either.

Fred's video with the Palo Alto Weekly is worth watching.

22 people like this
Posted by resident
a resident of College Terrace
on Apr 12, 2016 at 11:44 am

TCE - the gift that keeps giving. Thank you Stanford.

15 people like this
Posted by Sean
a resident of College Terrace
on Apr 12, 2016 at 1:05 pm

This absurd concern about TCE is a device for local environmental alarmists to gain and maintain political power. [Portion removed.]

2 people like this
Posted by resident
a resident of College Terrace
on Apr 12, 2016 at 5:20 pm

[Post removed.]

21 people like this
Posted by Terrace Antelope
a resident of College Terrace
on Apr 12, 2016 at 6:23 pm

Terrace Antelope is a registered user.

Why complain about Fred trying to help keep us all safe and healthy... I for one am thankful he's taking the time to do and I don't think it will hurt our ability to be heard in the future.

8 people like this
Posted by Unconcerned neighbor
a resident of College Terrace
on Apr 12, 2016 at 6:24 pm

I live in College Terrace and I'm inclined to trust the state Department of Toxic Substances Control over my local residents' association. Just my 2 cents.

3 people like this
Posted by @Sean
a resident of Mountain View
on Apr 12, 2016 at 6:36 pm

[Post removed.]

3 people like this
Posted by Boo!
a resident of Crescent Park
on Apr 12, 2016 at 6:58 pm

[Post removed.]

3 people like this
Posted by resident
a resident of College Terrace
on Apr 13, 2016 at 11:25 am

TCe been there for years and years. Nobody was concerned then. Kind of funny.

19 people like this
Posted by resident
a resident of College Terrace
on Apr 13, 2016 at 11:40 am

Water pollution was a huge deal during the 1980s. The Feds designated high-pollution Superfund sites, including some here in Palo Alto. Cleanup efforts quieted during the Reagan/Bush/recession years. Maybe public awareness is picking up now that the economy is improving and we have enough money to finally cleanup these sites.

5 people like this
Posted by resident
a resident of College Terrace
on Apr 13, 2016 at 1:42 pm

Superfund is where soccer fields are. Shell we star there?

20 people like this
Posted by Trust Issues
a resident of Another Palo Alto neighborhood
on Apr 13, 2016 at 4:12 pm

Stanford is not trustworthy, at least not in its business dealings.

Need any more be said?

16 people like this
Posted by Ahem
a resident of Another Palo Alto neighborhood
on Apr 13, 2016 at 6:17 pm

This is not your grandfather's Leland Stanford Junior University. Over the last two decades "Stanford" has evolved into the University of Phoenix on steroids.

"Stanford" is not just a University. Today's "Stanford" is essentially a corporate conglomerate that has diversified into several industries outside of the education market, and now competes in the health care (400 clinics!), hospitality (hotel), housing development, and the commercial real-estate businesses (among others).

Stanford Land Management (the developer of University Terrace) is just a business unit of the diversified "Stanford" conglomerate. Palo Alto residents, and Leland Stanford Junior University students and employees should not expect Stanford Land Management to treat them any differently, than any other for-profit corporate bureaucracy.

3 people like this
Posted by Stanford and Palo Alto
a resident of Stanford
on Apr 15, 2016 at 3:27 pm

Some of the more public manipulations by Stanford include
* Stanford hired a former mayor of Palo Alto (and developer's attorney) and gave her a benign title, something like Communications Director. She is a land-use attorney and is now a Vice President.

* Not long ago Palo Alto's then Planning Director (Steve Emslie) hired Andy Coe, a Stanford PR exec. to be Interim Deputy Director in the Planning and Community Environment dept. Coe "resigned" his Stanford post. He has no education or experience in planning.
It became a public scandal and it was rumored that the planning staff also objected.
Web Link
Coe resigned and returned to his Stanford job.
I believe he is now Chief Government and Community Relations Officer,
Stanford Hospital.

These are just some manipulations that became public.

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

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