The files on about 75 workers from across the Prairies included their names, social insurance numbers and earnings, according to the report.
Statistics Canada acknowledged it goofed. Global said the statistics agency intends to apologize to every person listed in the files.
The federal office of the privacy commissioner is investigating the breach.
Census worker Melissa Mouat, from Calgary, was among people angered that employment records made it to auction of used federal government furniture last weekend. "I think it's kind of a pathetic irony that I spent my entire summer reassuring (census respondents) that, no, you can give me this information , it will be safe with me -- and then they go off and sell mine," the census worker said.
"How difficult is it?" Mouat asked. "I know these people are disorganized but all you have to do is open the drawer and remove the information. That's my stuff and I'm not OK with that."
She expressed concern that criminals could get their hands on personal information. "Identity theft is huge."
Her father, Thomas Mouat, who also worked on the census, said: "They're telling everybody that the data is safe and then they're including my data for free with a filing cabinet that somebody purchased second-hand from them."
Global did not identify the person who bought the filing cabinet, but said it was sold at Edmonton's Gary Hanna Auctions.
Gary Hanna said his auction house receives truckloads of used government furniture. He said sometimes there are files.
"We try to check everything when it comes in but it's difficult, when we're running a sale a week, to catch everything," Hanna said.
Jerry Page, Statistics Canada director for the western region, said the agency has detailed written instructions in place to check each piece of furniture before sending it to auction.
"I'm appalled, frankly. I'm responsible and I have to take total responsibility for it," Page said.
"Obviously I'm not going to open every file drawer personally in 12 offices across Western Canada but at the end of the day the buck stops here.
"Somebody didn't do their job in this case, I'm sorry to say."
Raymond D'Aoust, assistant federal privacy commissioner, said the privacy office is always concerned when personal information leaks out. "We are looking into it."