That massive data breach we wrote about last week was apparently much worse than first reported; it now looks like the (possibly Chinese) hackers may have the personal data of every single US government employee, including retirees and former employees.

If true, this will go down as the worst security failure in history.

J. David Cox, president of the American Federation of Government Employees, said in a letter to OPM director Katherine Archuleta that based on OPM’s internal briefings, “We believe that the Central Personnel Data File was the targeted database, and that the hackers are now in possession of all personnel data for every federal employee, every federal retiree, and up to one million former federal employees.”

The OPM data file contains the records of non-military, non-intelligence executive branch employees, which covers most federal civilian employees but not, for example, members of Congress and their staffs.

The union believes the hackers stole military records and veterans’ status information, address, birth date, job and pay history, health insurance, life insurance, and pension information; and age, gender and race data, he said. The letter was obtained by The Associated Press.

ABC News is reporting that the hack of the federal Office of Personnel Management went undetected for more than a year.