OAKLAND — A Santa Clara county man is suing a Bay Area stem cell research and development company on allegations he was fired from a senior management job for voicing concerns about a manufacturing practices he says puts stem cell therapy patients’ lives at risk.

Rob Williams’ wrongful termination and retaliation lawsuit against StemCells was filed in Alameda County Superior Court this week and seeks punitive damages against the Newark-based, publicly traded company that receives millions in government and private grants.

StemCells hired Williams in December to oversee the facility where stem cells cultures are cultivated for clinical trials. The lawsuit alleges he was fired in May in retaliation for making complaints about “dangers/defective products that the company was releasing into the commerce stream for human clinical trials.”

StemCells, Inc. spokeswoman Andrea Flynn said the allegations are without merit and Williams was terminated for performance deficiencies.

“The elements of manufacturing practices that concerned Mr. Williams were immediately and carefully reviewed by the company,” Flynn wrote in an email. “The company’s primary concern has always been, and will continue to be, the safety and tolerability of stem cell transplantation in its clinical trials.

“To date, no patients participating in the clinical studies have experienced any product related safety concerns,” Flynn wrote.

Daniel…