The Finnish Social Security Institution (Kela) has apologized for a possible breach of its obligation to maintain the confidentiality of its clients' data.
In a press release, the agency explained that the personal data of 80,000 customers could have been potentially exposed due to the use of a new type of paper that allows to see through the address window of the envelope.
The case affects a mailing of 80,000 letters between August 26 and 27.
"Although the problem was detected quickly, the letters unfortunately had time to leave to the customers. The paper quality has now been changed. We are sorry for our mistake," says Kela's IT Director Jukka Melanen.
Kela, who prints around 60,000 letters daily, no longer uses the type of paper that caused the problem.
The case has been reported to the Finnish Data Protection Commissioner.