PALO ALTO (CBS SF) — Stanford University is making some big changes to a housing project after a potentially cancer-causing toxin was found in the soil.

The university is still moving forward with the project after the state’s toxic substances control department gave the project the green light.

But one neighbor KPIX 5 talked to Wednesday night wants more data.

“I just want confirmation that it’s safe,” Ed Schmitt, Vice President of the College Terrace Residents Association said.

Schmitt is concerned that Stanford’s massive new faculty housing project across the street from his home is being built on soil containing trichloroethylene, or TCE.  TCE is a chemical found in degreasers, and was recently found on the university’s construction site.

“Where’s the data? Assure us that we’re safe. That’s all. That’s all we’re asking,” Schmitt said.

TCE is a carcinogen that when found in soil under a home, its vapors can creep through the foundation, and seep inside to build up in possibly dangerous concentrations.

Stanford says the project is safe, but is taking precautions by adding fresh soil in areas where TCE was found, moving the homes far away from contaminated soil, and putting protective vapor barriers under all the affected homes.

Still, Schmitt worries rains from El Nino could spread TCE to the rest of the neighborhood.

“I don’t understand how rain comes down, washes into this hole, without carrying some of the toxic materials with it,” Schmitt said.

Stanford says that given how far down TCE was found, sometimes as deep as 25 feet underground that exposure is highly unlikely.

Years ago, PCB was also found on that site, but has since been cleaned up.