For two years, Rong Yuan, a trained metallurgist, worried that she was going crazy. Her hair began falling out due to chronic nausea and vomiting, but doctors couldn’t figure out what was causing her mysterious illness.
When her mother noticed a strange taste in the water in the bottle she kept on her desk at the Berkeley Engineering and Research Center, she considered a horrifying explanation.
Maybe she was poisoned.
Yuan decided to secretly install a camera in her workplace, and the footage captured made her stomach twitch. In a video from March 4, 2019, her colleague David Xu can be seen approaching her desk, pouring a substance into a bottle, screwing the cap back on, and quickly walking away.
Tests showed that water samples from her bottles contained levels of the toxic heavy metal cadmium that far exceeded federal drinking water limits, court documents state. Xu was arrested in 2019 and ultimately convicted of one count of felony poisoning. His motive for the crime is unclear.
On Monday, a judge granted Xu’s request to dismiss the felony charges after his probation ended earlier this year.
Yuan has avoided public attention for years, but said she recently decided to break her silence because she feared Xu might find a job at another company and continue harming others.
“Once the judge approves his application, no company will be able to find criminal records based on background searches; now they also need to conduct Internet searches,” Yuan told The Times on Tuesday.
She initially posted the video and spoke to the San Francisco Standard last week after learning of his upcoming hearing.
Under California law, a judge must dismiss the intoxication charge if all probation conditions are met.
“We join the victims in opposing this motion under Penal Code Section 1203.4,” the Alameda District said. Atty. Ursula Dixon released a statement Tuesday. “The court granted the motion over objections. We hope the survivors can continue to heal emotionally and physically from this shocking event.”
Yuan said she had been dealing with chronic health issues for years and believed her father’s death last September was caused by some contaminated water he ingested. In 2019, Ms. Yuan, her mother and father all tested positive for cadmium in their blood.
Xu was charged in 2019 with attempted premeditated murder and special circumstances causing grievous bodily harm, as well as two counts of aggravated intoxication. After several days in custody, he posted $2 million bail and was released under GPS monitoring, allowing him to resume a semi-normal life with his family as criminal proceedings dragged on for years.
In 2023, then-Alameda County Dist. Atty. Pamela Price offered him a plea deal for felony poisoning without any additional jail time. During the sentencing hearing, the judge said the deal was “very generous” considering everything in the case, and doubled his probation from one year to two years, SF Standard reported. Xu never served any additional prison time.
Price was elected in 2022 on a platform of criminal justice reform but was recalled by voters in 2024 frustrated by critics who said she was too lenient on criminals.
“The system has failed me,” Yuan told The Times. “He didn’t stay in jail.”
According to the Standard, Xu’s defense team presented a toxicologist’s report in court that concluded Yuan was unlikely to continue to suffer adverse health effects from cadmium.
Last week, Yuan published a research paper on the long-term effects of cadmium poisoning on herself, her mother and her father.
According to the study, she began experiencing symptoms of nausea, retching, migraines, shortness of breath and hair loss in February 2017, around the time she believed Xu began to poison her. Later that year, she suffered multiple bouts of violent vomiting, causing her to stay home from work.
She wrote that in 2018, she continued to experience severe symptoms of vomiting and diarrhea after drinking water in the office, prompting her parents to fly to the United States to care for her.
“In November and December 2018, I brought water home from get off work twice, and my mother used the water to cook porridge,” she wrote in the newspaper. “After every meal, my whole family would have acute episodes of severe vomiting, watery diarrhea and extreme weakness.”
She wrote that before drinking water, her father’s high blood pressure was under control and he walked six miles a day. Over the next few years, his symptoms worsened, he suffered repeated strokes, and he died of heart failure in 2025.
She wrote that she still suffered from liver and gastrointestinal problems, which she attributed to cadmium poisoning.
“Cadmium stays in the human body for a long time and causes lasting damage to my health,” Yuan told The Times. “My father passed away; my health and my mother’s suffered.”
Former Times staff writer Alejandra Reyes-Velard contributed to this report.