WASHINGTON — The National Security Agency declassified three secret court opinions Wednesday showing how it scooped up as many as 56,000 emails and other communications by Americans not connected to terrorism annually over three years, revealed the error to the court and then fixed the problem.
Director of National Intelligence James Clapper authorized the release.
The opinions show that when the NSA reported its inadvertent gathering of American-based Internet traffic to the court in 2011, the Foreign Intelligence Surveillance Court ordered the agency to find ways to limit what it collects and how long it keeps it.
Three senior U.S. intelligence officials said Wednesday that national security officials realized the extent of its inadvertent collection of Americans' data from fiber optic cables in September 2011. One of the officials said the problem became apparent during internal discussions between NSA and Justice Department officials about the program's technical operation.
"They were having a discussion and a light bulb went on," the official said.
The problem, according to the officials, was that the top secret Internet-sweeping operation, which was targeting metadata contained in the emails of foreign users, was also amassing thousands of emails that were bundled up with the targeted materials. Because many web mail services use such bundled transmissions, the official said, it was impossible to collect the targeted materials without also sweeping up data from innocent domestic U.S. users.
The officials did not explain, however, why they did not prepare for that possibility when the surveillance program was created and why they discovered it only after the program was well under way.