A data tape containing information from 12,799 electricity bills has been lost.
Old billing information, names and addresses are included on the record of payment demands produced on August 10 last year, NIE Energy said. It did not contain any banking details but the electricity company has written to customers.
The latest loss follows a string of similar lapses involving child benefit claimants and car drivers, among others.
The tape did not contain any bank, debit card or any other similar information that would be classified as sensitive under the Data Protection Act.
It held details such as account name and address, customer number, bill amount, previous payment and account balance from electricity bills dated August 10, 2009.
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