New details have surfaced in the investigation into an apparent unintentional poisoning at Atria Park of San Mateo assisted living facility that killed one person and sent two more to the hospital.
According to sources with direct knowledge of the investigation, security video shows a worker using a chemical cleaner - now identified as Ecolab Ultra Klene. The chemical comes in a large container, and the worker decided to pour some into a smaller jug.
However, the jug the worker chose is the same type as those the facility uses to serve fruit juice. Another worker confused the containers and served the chemical to the residents.
Family members of the 93-year-old woman who died of the poisoning said she was a longtime resident of San Mateo with nine children who all want answers.
"This is an egregious mistake, and it's not one you're going to see too often," said Niall McCarthy, who is not associated with the case but is an attorney specializing in elder abuse in the county.
"Under California law, the definition of neglect of a senior citizen is failing to protect them from safety hazards," he said. "So not only here did they fail to protect them from safety hazards, they created the safety hazard."
Kathryn Stebner, another elder abuse attorney, said she has filed two elder abuse lawsuits against the facility. In at least one of those cases, Stebner claims a resident died due to negligence.
"It didn't come in a juice container if it's poison, so I actually have a hard time believing that," she said.
The district attorney told NBC Bay Area his office is not involved in the case because, as of now, there's no evidence the poisoning was intentional or criminal.
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Police continue to investigate the case.
Editors note: An earlier version of this article noted a different Ecolab product. We have since learned the cleaner involved was Ecolab Ultra Klene.