On March 4, 2019, a hidden camera inside Berkeley Engineering and Research captured senior materials engineer David Xu pouring a substance into coworker Rong Yuan's water bottle. Lab tests later revealed cadmium levels in the water 3.5 million times above the federal threshold — cadmium being a toxic heavy metal used in industrial battery production and linked to kidney failure, bone disease, and cancer.
An Alameda County judge just granted Xu's request to have his felony conviction expunged.
Yuan had suspected something was wrong for months before he got proof. In January 2019, his mother visited him at work and noticed a strange taste and smell in his water. Yuan installed the hidden camera on February 11, 2019. Three weeks later, the footage caught Xu in the act. Berkeley police arrested him. The Alameda County District Attorney's Office charged him with a felony.
Then California's criminal justice system did what California's criminal justice system does. Xu entered a no-contest plea — accepting the conviction without admitting guilt — and prosecutors agreed to reduce the charge. His sentence: two years of probation. Not two years in prison. Two years of checking in with an officer. He completed probation in March of this year, and on October 12, the judge signed off on wiping the record entirely.
Yuan asked for $500,000 in restitution. He received $7,000. The judge at the time of sentencing called the probation deal "extremely generous, considering everything in this case." Generous is one word for it.
"My blood was frozen," Yuan said of watching the surveillance footage. "I cannot let him go." He fought the plea deal. He fought the reduced charge. He told the court Xu's actions were deliberate, methodical, repeated. "It's planned," Yuan said. "I don't think he deserves a second chance."
The court gave Xu a second chance anyway. And then a third — erasing the conviction from his record so future employers would never know that a materials engineer with access to industrial chemicals used them on a colleague's drinking water.
The restitution gap tells you everything about where the priorities landed. Yuan asked for half a million dollars for what amounts to months of being slowly poisoned at work. The system returned $7,000 — roughly the cost of a used Honda Civic — and moved on. Yuan's father died last year. Yuan has said he believes the stress of the case contributed.
California has spent a decade systematically lowering the consequences for criminal behavior. Shoplifting under $950 is effectively decriminalized. Drug possession was reclassified. Property crime goes uninvestigated in half the major cities. But there was always a line — violence against another person, poisoning, the kind of premeditated act that separates a mistake from malice. Xu didn't snap. He didn't act in the heat of the moment. He walked into a workplace, day after day, with a toxic substance, and put it in another man's water.
The expungement means Xu's record is clean. No felony. No conviction visible on a background check. A materials engineer who poisoned a coworker with cadmium at 3.5 million times the safe level walks into his next job interview with a blank slate.
