It was not just the information on 4.2 million Federal employees. It also was the information of 21.5 Americans who had a background check run on them by the government. This includes independent contractors who were checked out because they were providing goods or services to the government any time over the last 15 years. If like me you required a background check to provide services to the government, your personal data may be at risk.
http://thehill.com/policy/cybersecurity/248091-doi-scrambles-to-patch-security-holes-after-opm-hack