In a major privacy breach, 18 hard drives used by the Kanagawa Prefectural Government to store taxpayers' data were auctioned online over the summer instead of being destroyed, prefectural officials disclosed Friday.

The hard drives were sold by an employee of a Tokyo-based recycling company that had been commissioned to scrap them. Nine have been retrieved by the prefecture but the rest remain unaccounted for.

The situation came to light after a man contacted the prefectural government after buying nine of them. Kanagawa officials are asking that anyone who may unwittingly come into possession of the data refrain from disclosing it.