Raleigh, N.C. — Wake County schools sent out thousands of postcards to parents that inadvertently contained their children’s Social Security numbers, officials said Thursday.

Michael Evans, a spokesman for the Wake County Public School System, said the postcards were reminders for parents who opted to send their children to magnet or traditional calendar schools to let the district know if they want to keep their children there.

"A programming error caused Social Security numbers to be printed on some address labels,” Evans said.

Of the 15,000 postcards that were sent out across the district, about 5,000 had Social Security numbers printed on them.

“Those Social Security numbers should be locked down,” said parent Karen Newton.

Newton said the two postcards that she received contained both her daughters' Social Security numbers.

“There are people out there who will figure out…these are Social Security numbers and could lift them. I think it is very irresponsible,” Newton said.

Evans said the error can be attributed to an old system the district used, which used a student’s Social Security number as their nine-digit identification number. The district’s new system assigns a random nine-digit number to students.

Students that were already entered in to the old system were still assigned their Social Security number as an identification number.

Evans said the computer pulled the wrong fill causing some students to be identified by their Social Security number. The error affected students who were in elementary school when the old system was in place. Those students would be in middle or high school now.

“We feel terrible about it,” Evans said.

Evans said the district is doing a cross-reference check and notifying the state Attorney General’s Office, as well as the Wake County Board of Education. Parents will be notified individually.

“We are going to be offering them a year of free credit report checks for their families,” Evans said.

The school system will pay $20 per student for each credit check.