County officials are looking for a missing computer disk that contained the names, addresses, Social Security numbers and other personal information of thousands of home health care workers and their clients.
The disk was lost last week after the county sent it by courier to a software vendor's office in San Jose to determine workers' eligibility for health care benefits, county officials said.
"We've been doing this for three years and there has never been a glitch. But it's missing and we don't know what happened," said Kristin Bengyel, executive director of the county's program that oversees 10,000 home-care workers.
Officials at the San Jose software company, Refined Technologies Inc., said they never received the disk. The courier service, DHL, told county officials that the file was delivered May 10, though the county didn't require anyone to sign for the delivery.
"Best case is that nothing has been made public, but clearly this is a vulnerability and we've talked about coming up with a different procedure," said County Administrative Officer Bart Bohn.