The New York Police Department has unmarked vans that can X-ray nearby objects, and the public knows little about them: how many the department has, who's being examined, or what the vehicles cost, for example. To learn more about the vans—whose radiation could raise health concerns—ProPublica filed a Freedom of Information request three years ago. But the NYPD refused to release information that it said could "permit those seeking to evade detection to conform their conduct to the times, places, and methods that avoid NYPD presence and are thus most likely to yield a successful attack." Last month, however, a judge finally called on the NYPD to release material on the vehicles, ProPublica reports.
"The hallmark of our great nation is that it is a democracy, with a transparent government," the state Supreme Court judge said. Other government departments have provided information about the vehicles, which are also used, for example, at border crossings. The "backscatter" vans, ProPublica reports, use technology similar to old airport scanners. They emit about twice the radiation of such scanners, but that's far less than what's emitted by medical X-ray machines. "It's not that the radiation from these machines is very high," a physicist earlier told ProPublica. "It's, 'Does the benefit outweigh the risk?'" There are also questions over privacy. The NYPD, however, plans to appeal the ruling on safety grounds.