Exterior view of the Facebook corporate office in Dublin, Ireland. Shutterstock.com

The Irish Data Protection Commission announced Wednesday that it had launched an investigation into Facebook, likely the first such inquiry of a major tech company since the implementation of the European Union’s General Data Protection Regulation back in May.

The IDPC’s investigation, which was announced via tweet, was spurred by Facebook’s announcement Sept. 28 that a data breach on the platform impacted approximately 50 million users, less than 10 percent of whom are reported to be EU residents. The IDPC is responsible for upholding EU data privacy laws in Ireland, where Facebook’s European headquarters are located.

“In particular, the investigation will examine Facebook’s compliance with its obligation under the General Data Protection Regulation (GDPR) to implement appropriate technical and organisational measures to ensure the security and safeguarding of the personal data it processes,” the IDPC tweeted.

Menlo Park, California-based Facebook is the first major U.S. tech company to report a large data breach since the GDPR’s implementation date, and the Irish commission’s handling of the hack could set the standard for future investigations.

The handling of breaches could change under the GDPR regime, which sets hefty fines for companies that don’t strongly protect user data. Fines can result from not informing impacted users of an incursion within 72 hours. Facebook informed users of the breach Sept. 28 and said in a blog post that the problem was discovered Sept. 25.

The company could be hit with a fine if the EU determines Facebook did not take the necessary steps to prevent a data breach or broke other GDPR regulations. The highest fine a company can face under GDPR is 4 percent of its annual turnover—about $1.63 billion for Facebook.

Facebook’s post-breach blog post from vice president of product management Guy Rosen outlined the company’s steps to address the hack. He said that hackers used the platform’s “view as” security feature to steal Facebook access tokens and subsequently take over user accounts.

Facebook said Sept. 28 that law enforcement had already been contacted, the vulnerability in its code had been fixed and nearly 90 million accounts’ access tokens were reset to boost security. The “view as” feature was also disabled.

Rosen wrote Facebook had launched its own investigation. According to a statement Wednesday, the tech company has also been working with the IDPC.

“We have been in close contact with the IDPC since we have become aware of the security attack and will continue to cooperate with their investigation,” a Facebook spokesperson said.

The data breach is just one of Facebook’s many recent troubles. Last week, the social network was sued by its former content moderators for allegedly traumatizing them with disturbing images, videos and other posts on its platform.

Facebook has also faced scrutiny over the Cambridge Analytica data breach, which was revealed in March 2018. Political data firm Cambridge Analytica harvested data from millions of Facebook accounts and allegedly used the information to influence elections, including the U.S. 2016 presidential race.

In July, U.K. Information Commissioner Elizabeth Denham said she intended to fine Facebook £500,000 ($647,517.50) for the Cambridge Analytica breach because, as she told Politico and other outlets, the company “failed to provide the protections required under data protection laws.”