Information relating to 8000 claims was accidentally released to an EQC customer and their lawyer last week.
Both EQC and the lawyer involved took steps to fix the problem and are waiting on confirmation that the customer who received the information has deleted it.
EQC boss Sid Miller says a staff member failed to follow several key security steps including well-established password protection of the documents despite receiving the proper training.
He says it's disappointing and shows their systems, processes and training need more tightening.