The office of privacy commissioner Jennifer Stoddart says it received formal complaints after a Human Resources and Skills Development Canada employee lost a USB key containing the personal information — including social insurance numbers — of about 5,000 Canadians.
Anne-Marie Hayden, a spokeswoman for Stoddart, says the privacy commissioner has also taken close to 200 calls from people expressing concern about the breach.
Human Resources says an extensive search for the key continues.
The department has no evidence that information on the missing key has been used for fraudulent purposes.
A spokeswoman for Human Resources Minister Diane Finley calls the loss of the key a serious and completely unacceptable incident.