LONDON – Ireland's data regulator has launched an investigation of Facebook over a recent data breach that allowed hackers access to 50 million accounts. The probe could potentially cost Facebook more than $1.6 billion in fines. The Irish Data Protection Commission said Wednesday that it will look into whether the U.S. social media company complied with European regulations that went into effect earlier this year covering data protection. It's the latest headache for Facebook in Europe, where authorities are turning up the heat on dominant tech firms over data protection. Last month, European Union consumer protection chief Vera Jourova said that she was growing impatient with Facebook for being too slow in clarifying the fine print in its terms of service covering what happens to user data and warned that the company could face sanctions.