The government will start scanning Facebook, Twitter, Instagram and other social media accounts of thousands of federal employees and contractors applying and re-applying for security clearances in a first-ever policy released Friday.

Federal investigators looking at applicants’ backgrounds to determine their trustworthiness will not ask for passwords or log in to private accounts, limiting their searches to public postings. And when they find information that has no relevance to whether they should have access to classified information, it will be wiped from government servers, the policy promises.

The directive from Director of National Intelligence James Clapper is an official acknowledgment that social media is a tool as important to security clearances as interviews with friends and family and other checks the government has made for decades.

More and more people, whether suspected terrorists or those who have allegedly committed mass shootings, have posted their intentions on public social media sites or talked about violent views. Just this week, the Secret Service said it would investigate Donald Trump’s former butler over his racially explicit Facebook posts calling for President Obama to be killed.

“Agencies make security clearance decisions using a ‘whole person approach’ to assessing who is an acceptable security risk,” Beth Cobert, acting director of the Office of Personnel Management, told lawmakers Friday at a hearing on the new policy.