Border-patrol drones being borrowed by other agencies more often than previously known The records show that the border-­patrol drones are being commissioned by other agencies more often than previously known. Most of the missions are performed for the Coast Guard, the Drug Enforcement Administration and immigration authorities. But they also aid in disaster relief and in the search for marijuana crops, methamphetamine labs and missing persons, among other missions not directly related to border protection. Because they have sophisticated cameras and can remain in flight for many hours at a time, drones create novel privacy challenges. Civil libertarians have argued that these aircraft could lead to persistent visual surveillance of Americans on private property. Government lawyers have argued, however, that there is no meaningful legal distinction between the use of unmanned and piloted aircraft for surveillance. Hundreds of missions The issue has become a hot topic in Congress; the Senate Commerce, Science and Transportation Committee is scheduled to hold a hearing on the subject Wednesday. For now, drone flights in the United States are tightly restricted for safety reasons. Other than the military, Customs and Border Protection is one of the few agencies permitted by the Federal Aviation Administration to fly unmanned aircraft on a daily basis within the country's borders. As a result, Customs and Border Protection is facing heavy demand to fly its unarmed drones to benefit other law enforcement agencies that lack their own. In 2010, for example, Customs and Border Protection conducted 76 drone missions for other agencies. The next year, that number quadrupled, and it remained at nearly the same level in 2012. Although the border agency has acknowledged that it flies drones for other law-enforcement departments, it has revealed little about the number and precise nature of the missions. All told, Customs and Border Protection flew 687 drone missions for other agencies from 2010 to 2012, according to the records provided to the San Francisco-­based Electronic Frontier Foundation. Last summer, the border agency released a batch of records indicating that it had flown fewer than 500 missions during that period. Officials offered no explanation for why the earlier release of documents was incomplete. Congress has directed the FAA to gradually open the national airspace to public and commercial drone traffic in the coming years. In the meantime, however, there is a huge, unfed appetite among police agencies for drones and their powerful surveillance tools, which include infrared cameras and specialized radar. Customs and Border Protection has a fleet of 10 unarmed Predator B drones. They are virtually identical to an Air Force drone known as the Reaper. Both are manufactured by General Atomics, a major drone producer based in Southern California. The FBI and other federal law enforcement agencies have their own drones, but they are more rudimentary than those operated by Customs and Border Protection. The Defense Department is prohibited from using its drones in the United States for law enforcement David V. Aguilar, who was the acting chief of Customs and Border Protection until he retired last year, said calls for surveillance help from other agencies began to jump as word got out about the drones" capabilities. "As the other entities found out we were able to fly, and where we were able to fly, the requests started to come up," said Aguilar, who is a partner at Global Security & Intelligence Strategies, a Washington-based consulting firm. He said the requests were granted only if there was a pressing law enforcement purpose or a public safety emergency. "There was a sensitivity attached to this," he said. Customs and Border Protection flies its drones within a 25-mile-wide corridor along the nation's northern and southern borders, as well as over the Caribbean Sea and Gulf of Mexico. Jenny Burke, a spokeswoman for the agency, said 95 percent of its drone flights "are devoted to CBP's border security mission." She said that the drones are sometimes deployed in support of federal disaster-response efforts and that they can be used to provide aerial mapping of flood zones and storm-stricken areas. Sophisticated sensors The logs, which were heavily redacted before being released, detail hundreds of missions and attempted missions. In every case, the name of the government agency borrowing the drones was blacked out, but CBP officials separately provided overall totals of how often various agencies used its drones. The sensors mounted on the drones, records show, often were equipped with radar technology capable of detecting movement on the ground. The drone logs record many uses of a surveillance system called VADER, for Vehicle and Dismount Exploitation Radar, to spot individual people and vehicles, though its reliability varied. When one agency used a drone to check out reports of "a launching device" that shot bundles of contraband between homes on both sides of the U.S.-Mexico border, the drone detected "no suspicious activity" during its flight in May 2012. Yet in other cases, the drones watched drugs move across the border in backpacks, speedboats, pickup trucks and river rafts. In June 2012, a drone equipped with VADER spotted a truck south of the border installing a temporary ramp over a fence. A silver Chevrolet Suburban SUV soon drove over the ramp, clearing the fence, in full view of the drone. Agents alerted to the activity recovered 2,317 pounds of marijuana. Jennifer Lynch, a senior staff attorney with the Electronic Frontier Foundation, expressed frustration that CBP officials would not release the names of sheriff departments for which the agency flew drones. She also expressed concern about policies allowing for indefinite retention of video feeds and other data collected during flights related to investigations. "We don't know what's happening with that data, and that creates a bigger privacy risk," Lynch said.