China's hack into 32 million federal personnel records now stands as the biggest computer breach in American history, and threatens U.S. national security way more than the IT espionage of Edward Snowden and Chelsea Manning, according to a House chairman probing the attack.

"It's probably the biggest data breach in the history of our country, and certainly our government," said Rep. Jason Chaffetz, chairman of the House Oversight and Government Reform Committee.

"If you compare it to some of the things that happened with Snowden and Chelsea Manning, you're going to look back on this and say it was by far the biggest, most difficult to deal with, because you have so much information about people who are in the government," the Utah Republican said, adding, "This is a national intelligence problem that we will be dealing with for decades to come."

The China hack is deemed worse than the espionage of Chelsea Manning and Edward Snowden, said a House chairman. AP Photos

The New York Times reported on Sunday that officials fear that China will be able to identify spies inside the country from the information stolen from Office of Personnel Management computers.

Chaffetz revealed in a speech to the centrist Ripon Society last week that OPM was given strong warnings that its antiquated computer system was open for attack. The speech was later provided to Secrets.

"The Office of Personnel Management is working on a Cobol operating system — something that was implemented in the 1960s. It has no dual authentication, no encryption, and is something that the inspector general had been warning about for nearly a decade," he said.

"It got so bad last year that the inspector general literally wrote to the OPM director and said, 'Unplug it! Turn it off! You're going to lose all the data!' And sure enough, they did," he added.

Paul Bedard, the Washington Examiner's "Washington Secrets" columnist, can be contacted at pbedard@washingtonexaminer.com.