A cancer-causing chemical found at Stanford University's University Terrace housing development, which officials claim has not spread to the adjacent neighborhood, has been found in some College Terrace homes, according to a report submitted by several residents.
A professional hired by residents tested under 19 homes within about 100 to 200 feet of the site's border at 1601 California Ave. The consultant, Blayne Hartman, an expert in soil vapor sampling, analysis and intrusion, found levels of trichlorethylene (TCE) at six homes that exceeded the allowable levels mandated by state and federal Environmental Protection Agency guidelines. The data was analyzed by Ed Schmitt, a retired chemist and College Terrace resident, and the residents submitted a 32-page report to the Palo Alto City Attorney and the California Department of Toxic Substances Control (DTSC).
Stanford discovered the TCE and another hazardous chemical, polychlorinated biphenyl (PCB), after contractors demolished buildings at 1601 California Ave. in late 2015. The university, which is building 180 junior faculty residences at the site, submitted a revised subdivision map to the city that will relocate 29 residences and reconfigure some streets to avoid placing the homes on the most contaminated areas. On Tuesday, June 28, Stanford will ask the Palo Alto City Council to approve the map amendment.
City Planning and Community Environment Director Hillary Gitelman and City Manager James Keene are recommending the approval, according to a planning department memo.
But College Terrace residents say their consultant's findings demand that the city should postpone any approval until DTSC, which has oversight of hazardous material spills, has reviewed the new report and has signed off on a Preliminary Endangerment Assessment, according to a letter submitted to the city by resident Fred Balin, principal coordinator of the College Terrace study.
Stanford excavated 1,400 tons of dirt and removed the PCB, which clings to soil. But TCE, which was found to a depth of at least 25 feet, was not removed because it is present as vapor between soil particles, which is much harder to eliminate, according to assessments by university consultants. TCE exposure has been linked to kidney cancer and non-Hodgkin Lymphoma; short-term exposure can lead to birth defects in developing fetuses, according to the Environmental Protection Agency.
Stanford consultants have said the TCE poses no threat to College Terrace residents. University officials submitted a Hazardous Risk Assessment plan to the DTSC late last year, which proposes to move 29 planned residences within its development boundaries from atop the most contaminated spots. The university plans to go further than required by adding vapor barriers, ventilation and other measures to as-yet-to-be-constructed homes. But the plan offers no mitigation or protection for homes in College Terrace, which is just across California Avenue from the project site.
Stanford and DTSC have maintained that additional testing for vapor intrusion, which stopped at the project site's border on California Avenue, was not necessary. Stanford's consultants did not find evidence of TCE migration, and a March 18 finding by DTSC supported those results.
But the College Terrace testing found that in basements and crawl spaces of five homes the levels of TCE vapor exceeded state and federal maximum allowable "screening" levels by between 1.65 and 36.6 times above the federal and state Environmental Protection Agency's "screening" requirement of 0.48 micrograms per cubic meter. The crawl space levels ranged from 0.76 to 17.6 micrograms per cubic meter.
Hartman also tested the living rooms in those homes. In four of the five cases, a lower level of TCE was detected in the living room than in the crawl space, implying a source of TCE from below the first floor, according to a double-blind study, the report noted.
"The most likely mechanism for TCE to get into the crawl space area is by soil vapor diffusion from more concentrated soil areas," according to the report.
The testing did find potential anomalies. In the fifth home, the living room screening level was higher than that of the crawl space, raising the concern of an indoor source of TCE, such as contamination blown or tracked in; leaky, old cleaning or paint products or a non-representative crawl
space sample. Samples from a sixth home showed a living room TCE level higher than the federal/state screening level, although the crawl space measurement was below the allowable level.
Overall, five living rooms showed TCE concentrations ranging from 0.6 to 3.3 micrograms per cubic meter, or 1.25 to 6.8 times the federal/state level. The measurements ranged between 108 to 202.3 feet from Stanford's property line for the crawl space tests and 98 to 224.3 feet for the living room samples.
The report also sought to translate those numbers into relative cancer risk.
Based on the federal Environmental Protection Agency's equations for cancer risk, every TCE vapor concentration has an associated cancer risk. The state/federal 0.48 micrograms-per-cubic-meter level represents a one-in-a-million excess lifetime cancer risk. Cancer risks for crawl space/basement samples in excess of the federal/state 0.48 level are between one in a million to one in 27,000, according to the report.
"Even though the sample number is small, the data suggests there are higher levels of TCE in sampled homes found closer to the project's property line than only a hundred feet further away," the report noted. "Initial conclusion: The (DTSC) statement that 'the College Terrace community is safe with respect to potential vapor intrusion to constituents detected in soil vapor at University Terrace' is not supported by the data in this study."
Other residents support the College Terrace findings.
The city's staff report should describe long-term monitoring for the overall project site and the city should wait to review the proposed subdivision amendments until the DTSC review and after any additional requirements are completed by Stanford, Doria Summa and Margit Aramburu, wrote in a separate June 23 letter to the City Council.
The changes to the map Stanford has made are also not minor under the city's own definition, and the Planning and Transportation Commission should be directed to review the proposed design and improvement amendments as a new or revised filing, they wrote.
But the memo to the City Council from Gitelman and Keene disagreed with the residents' contentions and recommends that the City Council approve Stanford's proposed subdivision amendment. The final map deals with the subdivision of land and specifically addresses the contamination within the subdivided area, and that, in their view, is all that is required.
"The information regarding the off-site situation (College Terrace) should not affect the determination of the on-site situation," they wrote.
In separate request for comment made by the Weekly, city officials underlined that they view the TCE contamination at College Terrace as separate from the University Terrace site.
"DTSC has not yet determined the source of the off-site TCE identified in the residents' report. However, DTSC has thoroughly assessed the on-site TCE contamination and has informed the city and applicant that the revised layout coupled with passive mitigation measures make the site safe for residential habitation," Claudia Keith, chief communications officer for the city manager's office, forwarded on the city's behalf.
"There are multiple potential source of TCE in the area. In addition to former industrial uses in the area, consumer products containing TCE (cleaning products, spot removers, glues and adhesives) can also serve as indoor air sources," officials added.
Stanford spokeswoman Jean McCown said the university does not have much in the way of a comment. She said officials understand that DTSC is reviewing the residents' materials.
"The California Avenue edge of 1601 was extensively tested and no detectable levels of TCE were found," she said, noting DTSC's March 18 letter.
Keith said DTSC has informed the city that its agency will review the College Terrace sampling results, and, if warranted, will take follow-up actions.
"This is the appropriate next step and we look forward to hearing the results of DTSC's evaluation," Keith wrote.
DTSC officials said that Stanford hasn't yet proposed measures to address the area of most significant impact by the TCE and the process under DTSC's oversight hasn't concluded.
"At this point, we have just agreed that the risk assessment shows it is acceptable to construct the faculty housing where it is currently proposed," a spokesman said.
DTSC is reviewing the residents' report and officials will communicate with the community after the review is completed, he aid.
DTSC initially determined that the TCE would not be an intrusion into College Terrace because moving further away from the onsite sources the agency observed declining TCE levels. The chemical was not detected at concentrations above screening levels in the onsite soil gas samples nearest to the California Avenue boundary of the site, according to DTSC.