For at least six years, law enforcement officials working on a counternarcotics program have had routine access, using subpoenas, to an enormous AT&T database that contains the records of decades of Americans' phone calls parallel to but covering a far longer time than the National Security Agency's hotly disputed collection of phone call logs.
The Hemisphere Project, a partnership between federal and local drug officials and AT&T that has not previously been reported, involves an extremely close association between the government and the telecommunications giant.
The government pays AT&T to place its employees in drug-fighting units around the country. Those employees sit alongside Drug Enforcement Administration agents and local detectives and supply them with phone data from as far back as 1987.
The scale and longevity of the data storage appear to be unmatched by other government programs, including the NSA's gathering of phone call logs under the Patriot Act. The NSA stores the data for nearly all calls in the United States, including phone numbers and time and duration of calls, for five years. Unlike the NSA data, the Hemisphere data includes information on the locations of callers.
Hemisphere covers every call that passes through an AT&T switch not just those made by AT&T customers and includes calls dating back 26 years, according to Hemisphere training slides bearing the logo of the White House Office of National Drug Control Policy. About 4 billion call records are added to the database every day, the slides say; technical specialists say a single call may generate more than one record.
The slides were given to The New York Times by Drew Hendricks, a peace activist in Port Hadlock, Wash. He said he had received the PowerPoint presentation, which is unclassified but marked "Law enforcement sensitive," in response to a series of public information requests to West Coast police agencies.
The program was started in 2007, according to the slides, and has been carried out in great secrecy.
The Obama administration acknowledged the extraordinary scale of the Hemisphere database and the unusual embedding of AT&T employees in government drug units in three states.
But they said the project, which has proved especially useful in finding criminals who discard cellphones frequently to thwart government tracking, employed routine investigative procedures used in criminal cases for decades and posed no novel privacy issues.
Crucially, they said, the phone data is stored by AT&T and not by the government, as in the NSA program. It is queried for phone numbers of interest mainly using what are called "administrative subpoenas," those issued not by a grand jury or a judge but by a federal agency, in this case the DEA.
Brian Fallon, a Justice Department spokesman, said the program was paid for by the DEA and the White House drug policy office but that the cost was not immediately available. Officials said four AT&T employees are now working with the DEA.