The New York Times reports that European Union officials have accused major search engine providers such as Google, Yahoo! and Microsoft of violating user’s personal rights by storing private data for too long. The Article 29 Working Party, an EU advisory board made up of 27 European national privacy chiefs issued a letter to the three companies on Wednesday urging them to appoint outside auditors to ensure that practices used to render data collected from individuals anonymously truly removes all links to a person.

European Union rules state that search engines are required to remove all traceable links to individual computer users “completely and irrevocably” after six months. However, all three search engines currently keep data for longer than 180 days, in some cases up to 18 months. The search engines claim that the data – which includes all types of information that a computer user enters into a search engine field – is rendered anonymous, but the Article 29 Working Party believes this is not enough.

The letter singled out Google, the market share leader at 80 percent, for its privacy practices.

“Considering Google’s dominant position in almost every E.U. member state, with a market share of up to 95 percent in some national search engine markets, the company has a significant role in European citizens’ daily lives,” the European panel wrote. “The company’s apparent lack of focus in data retention is concerning.”