Responding to concerns from the Barron Park neighborhood about potential hazards of a nearby plating shop, Palo Alto officials are considering a new zoning law that would ban such operations near residential areas.

The City Council is set to discuss on Oct. 6 the city's next move in addressing neighborhood anxieties about the hazardous materials stored by Communication & Power Industries (CPI), a technology company that operates a plating shop at 607-811 Hansen Way. Though CPI has been in its current location since the 1950s, its plating shop expanded in 2006, when the company incorporated its San Carlos operations into the Palo Alto facility.

Since then, the company has been involved in at least three accidental releases of hazardous materials. In 2005, CPI released nitric acid gas, creating a noxious odor. In spring of 2008, the company was involved in two chemical spills, one in March in the company's rear driveway and another that took place in May and affected Matadero Creek. In the latter case, the company was found to have dumped 50 gallons of dilute wastewater containing copper and nickel because of "improper weekend shutdown of process equipment and improper opening of a containment valve that discharges to the creek," a report from the Department of Planning and Community Environment states.

Though the company has since reduced the quantities of hazardous materials stored onsite, neighbors have continued their calls for shutting down the operation. In 2012, the city completed an amortization study to determine how much time the city should give the company to close down its facility, should a decision to do so be made (the study determined that the time should be 20 years, with the clock starting to tick in 2006, when CPI last made a major upgrade to its plating shop).

After considerable pressure from Barron Park residents, the city also commissioned a risk assessment for the CPI site. In February, the consulting company AECOM released a study that considered various scenarios, including different types of chemical spills and a breach of nitric acid. It concluded that these events have a relatively low risk of impacting individuals off-site, though in one scenario, the consultants determined that off-site consequences could potentially extend 92 feet from the source.

Last month, another study was completed by AECOM with a focus on an "extreme event" such as a major earthquake that causes hazardous chemicals to mix in CPI's plating shop. Such an event would have a "toxic endpoint" (defined in the report as "air concentration of an acutely hazardous substance above which there may be serious acute health effect following a single short-term exposure") of 616 feet from the plating shop, AECOM found.

A companion study, performed by Albus-Keefe and Associates, considers a range of earthquake intensities that could cause a wholesale failure of the building. The study determined that it would take a peak ground acceleration of 1.07 g to 1.33 g (with g being the force of acceleration due to gravity) to cause the building to collapse. The lower-end acceleration of 1.07 g has a 1.1 percent chance of occurring in the next 50 years, the study found, while the higher-end acceleration of 1.33 g has a 0.4 percent chance of occurring during the same time span.

The study notes that current California Building Codes require structures similar to CPI's to be designed for earthquake events having a probability of exceedance equal to 2 percent in 50 years.

CPI, for its part, has persistently disputed neighbors' suggestions that its facilities are unsafe. In a February email to Palo Alto City Manager James Keene and Planning Director Hillary Gitelman, CPI's attorney characterized AECOM's report as validating the company's assertions about the low risk of its operations.

"I would think that CPI's neighbors would be thrilled by such a report," wrote Mark Steres of the firm Aleshire & Wynder, LLP. "Instead, the neighbors present at the meeting wanted to tear apart and discredit the AECOM report and did not believe the results. There appears to be a total distrust of CPI by the neighbors and a belief of a 'conspiracy' by CPI to do evil things. CPI is dismayed by this reaction as it cannot be farther from the truth."

Seres notes that CPI has been operating the site for more than 60 years and that "during this entire time there has not been one single neighbor harmed as a result of operations at CPI."

Keene responded by assuring that the city "has no intent to 'target' CPI" but noting that the city, at a minimum, would like to make sure "no new uses such as CPI are located within close proximity to residential zoning districts." The city's approach may also "contain procedures for existing uses to come into compliance with the revised provisions of code," Keene wrote in the March 20 letter to CPI.

He assured the company that the city "will hear and consider all relevant facts and perspectives and will make reasonable judgments based thereon."

"The relevant facts include those articulated in your letter but also the fact that AECOM's analysis of extreme events suggests some potential for limited off-site exposure in one scenario and the fact that neighbors of CPI have little trust in the company's ability and willingness to safeguard their health and safety," Keene wrote.