Energy supplier United Consumers has sent thousands of e-mails to customers containing e-mail addresses, home addresses and names of other customers. According to a supplier spokesperson, 2,865 customers have received the e-mail chain.

The data breach came about when sending the monthly update on the energy use of customers. When sending, the address of the previous addressee was not deleted, resulting in a large chain mail.

In this way, some customers received thousands of emails in a short time and could see the addresses and names of other customers. The energy consumption is not leaked through the mails. For this, customers must first log in.

According to United Consumers, the problem was discovered fairly quickly, which meant that the mailing could be stopped and the number of affected customers could be limited. The technical error has since been found and corrected. The energy supplier will now investigate how it could arise.

United Consumers will report the data breach to the Dutch Data Protection Authority, a spokesperson said. Once the internal investigation has been completed, the authority will be officially notified.

Affected customers will be informed by United Consumers on Tuesday via a text message.