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TCE Groundwater Contamination Persists Near California Avenue

Barron Park Association Foundation wants EPA to take over cleanup.

Trichloroethene (TCE), the chemical compound known to cause birth defects and cancer in lab animals, continues to contaminate groundwater in the California-Olive-Emerson neighborhood near California Avenue in Palo Alto, according to a report by Hewlett-Packard.

Based on a January HP quarterly TCE report, the Barron Park Association Foundation (BPAF), a nonprofit organization charged with monitoring TCE cleanup, identified  several residential and commercial mixed-use properties that have soil-gas levels far higher than legally acceptable levels.

Namely, properties at 195 Page Mill Rd., 200 and 345 Sheridan Ave., and Birch Plaza are at risk, say foundation board members. “Most at risk is 200 Sheridan, where the two-level underground garage penetrates the aquifers, and the lower garage level periodically has contaminated ground-water leak inside,” board member Bob Moss said. Moss is also for Palo Alto Patch.

The property at 200 Sheridan Ave. houses offices on the ground floor, a popular Italian restaurant called and residential units on the upper floors. The owner of the building, Harold Hoback, said the building periodically had leakage in the garage during the last rainy season, Moss said. If the TCE-contaminated water has leaked into the garage, the toxins will evaporate into the air and can go into living spaces and expose people, Moss said.

Within the past year, Hewlett-Packard has tested 195 Page Mill Rd. for soil-gas levels of TCE, according to BPAF. Tests showed levels of "23,000, 25,000 and 150,000 micrograms/liter, far higher than any acceptable level for potential TCE exposure," stated a March BPAF letter to the San Francisco Bay Regional Water Quality Control Board. Environmental Protection Agency soil-gas action levels are 500 micrograms/liter for residential and 1,000 for commercial, according to Moss. This standard applies to Palo Alto; however, the water board has not enforced the levels, according to BPAF.

At 365 Sheridan Ave., the residential building “has an enclosed underground garage that is highly likely to experience vapor intrusion from both the aquifer and soils,” BPAF wrote in a letter to the regional water quality control board. 

BPAF has pestered the water board to perform official testing on contaminated buildings. The water board has had oversight for cleanup of underground-water contamination from the Hewlett-Packard 620-640 Page Mill Rd. Superfund site since 1991. Hewlett-Packard first found TCE leakage in 1981 from this site, said BPAF board president David Chalton. The company, which used TCE to clean electronics, occupied the premises during the 1960s, '70s and '80s. Leakage could have at any time during those years, Chalton said.

The water board has to do official testing in order to force Hewlett-Packard to clean up the mess, Chalton said. Yet the board has done nothing new to address increased levels of TCE in the groundwater, Chalton said. To date, it still has not done any testing on the identified buildings, said Chalton.

In the past, Hewlett-Packard has cooperated with other areas of cleanup, but “they don’t want to spend the money unless required,” Chalton said. “That’s why we want the water board to do testing to see if TCE is really a problem or not. The water board has been reluctant to do that, and we have been trying to get the EPA to put pressure on it,” he said.

“We’ve been fighting them for eight years to do indoor sampling and to require new buildings to have proper vapor barriers to prevent soil gas from getting into buildings,” Moss said. “Basically, I’ve given up on the water board."

The city of Palo Alto must enact a law requiring developers to put in vapor barriers, Moss said. Palo Alto has not done anything because the water board has not recommended such barriers, he said.

Mountain View has had a city ordinance since 1993 requiring newly constructed buildings to have vapor barriers to prevent TCE gas from entering living and working spaces, Moss said. The EPA has aggressively cleaned up much of the contamination across 101 freeway from Moffett Field, he added. Nothing of the sort has happened in Palo Alto, he said.

“We already know the soil-gas levels at the Birch Plaza site are 6,400 micrograms/liter, which exceed action levels of 500 for residential and 1,000 for commercial,” Moss said. “The Birch Plaza project still has no requirement for vapor barriers or indoor air monitoring." Last November, the City Council approved construction plans for Birch Plaza, at 305 Grant Ave.

“We’re fed up with it,” Moss said.

Cleaning up the mess requires a long process of pumping contaminated water out of the ground and filtering it, Chalton said. Palo Alto uses an outdated 20-year old pump-and-treat system, which is inadequate and has caused TCE buildup in some wells, according to Moss.

The "existing pump and treat system seems to have reached saturation in VOC removal" and "apparently will not reduce the levels of  TCE to acceptable levels just by pump and treat," stated a BPAF letter to the water board. The BPAF has recommended a few alternatives to pumping, such as oxidation treatment and abiotic/biotic treatment.

Using the current pump-and-treat system would take 100 years to fully remove, the EPA and U.S. Navy has said, according to Moss. To date, however, neither the EPA nor the water board have done anything new to address ongoing high levels of TCE contamination in Palo Alto.

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