ABC News postulates the massive OPM hack somehow went undetected for more than a year:

However, U.S. officials speaking on the condition of anonymity say unequivocally such information was put at serious risk by the OPM hack. Of utmost concern are U.S. employees stationed overseas, including in countries such as China, whose government would covet personal information on relatives and contacts of American officials living in the communist country, according to officials.

“If the SF-86’s associated with this hack were, in their entirety, part of the stolen information, then that would mean the potential release of a staggering amount of information, affecting an exponential amount of people,” one U.S. official told ABC News on Sunday.

Acting as the government’s human resources division, OPM conducts about 90 percent of background investigations for the federal government. Information from SF-86 forms dating back three decades could have been exposed in the cyber-attack, which the U.S. government strongly suspects was carried out by hackers in China, sources said.

The term “asleep at the wheel” does not convey a strong enough message presenting how utterly unprepared OPM appears to have been to prevent, or at least be aware of, this attack.