A mailer sent by Aetna Student Health company informing students of available insurance plans for the 2013-14 academic year included students’ social security numbers on the address labels. [RED LETTERS added — actual information removed to protect privacy.]

Approximately 18,700 students’ social security numbers may be compromised after a mailing error caused the numbers to be printed on the outside of envelopes sent directly to students, University spokesperson McGregor McCance confirmed in an email Wednesday.

“The University is in the process of notifying students whose information was exposed,” McCance said. “The University will provide affected students free credit monitoring.”

Aetna Student Health, the organization which provides students health insurance if they buy through the University, sent out a mailer informing students of health insurance options for the 2013-14 academic year. Students’ social security numbers were printed on the line above their names on the address labels, though they were not labeled as such.

“We are aware of the unfortunate situation and regret that it occurred,” Aetna spokesperson Cynthia Michener said in an email. “We are working with the University to notify affected students and help ensure that an incident of this nature doesn’t happen again.”

“Our focus is on notifying those affected, providing them information regarding credit monitoring and assistance, and ensuring that such an incident will not occur again,” McCance said.