For more than three years, ProPublica has been fighting to force the NYPD to disclose the details of its fleet of X-ray vans. Earlier this year, New York State Supreme Court Judge Doris Ling-Cohan ruled that the NYPD couldn’t shield itself from Freedom of Information requests simply because disclosing fleet details could interefere with ongoing investigations. The New York Civil Liberties Union has filed an amicus curiae (friend of the court) briefing arguing against the NYPD’s position, but New York Police Commissioner Bill Bratton continues to stonewall reporters.

“Those are issues I’d prefer not to divulge to the public at this time,” Bratton said. “I will not talk about anything at all about this — it falls into the range of security and counter-terrorism activity that we engage in.”

That type of “It’s for your own good,” attitude is precisely the kind of carte blanche that created the modern NSA in the first place. The NYPD is neither a military organization nor a government agency tasked with protecting New Yorkers from far-flung threats across the globe. It’s a local police force that serves the needs of its own citizens, and its policies and practices must be open to civilian review. As the recently-filed amicus brief notes, “How is the NYPD ensuring that innocent New Yorkers are not subject to harmful x-ray radiation? How long is the NYPD keeping the images that it takes and who can look at them? Is the NYPD obtaining judicial authorization prior to taking images, and if so, what type of authorization? Is the technology funded by taxpayer money, and has the use of the vans justified the price tag? The current price tag is between $729,000 and $825,000 per van.

While these vehicles are referred to as X-ray vans, they don’t use conventional X-ray imaging. Instead, they rely on backscatter technology. Conventional X-ray machines detect hard and soft materials based on how much energy makes it through the target, while backscatter X-rays detect how much energy is reflected from the target. These are the machines that raised substantial privacy concerns when they were first deployed. The image below is Susan Hallowell, director of the Transportation Security Administration’s research lab.

The NYPD’s refusal to turn over information related to its use of these technologies runs afoul of multiple Supreme Court rulings and safety regulations. First, the Supreme Court has ruled in the past that using high-tech sensors to search a person’s house or person is illegal unless a warrant is obtained. Second, there’s very real concerns over the safety of backscatter X-ray devices. In her initial decision, Judge Ling-Cohan wrote:

Petitioner states in his affidavit, and respondent does not dispute, that: backscatter technology, previously deployed in European Union airports, was banned in 2011, because of health concerns; an internal presentation from American Science and Engineering, Inc., the company that manufactures the vans, determined that the vans deliver a radiation dose 40 percent larger than delivered by a backscatter airport scanner; bystanders present when the van is in use are exposed to the radiation that the van emits… moreover, petitioner maintains, and it is not disputed by the NYPD, that ‘there may be significant health risks associated with the use of backscatter x-ray devices as these machines use ionizing radiation, a type of radiation long known to mutate DNA and cause cancer.

Backscatter and the inverse square law

Without proper oversight, it’s impossible to know if the NYPD is deploying its backscatter technology in a manner that guarantees the safety of both its own drivers and the general public. Backscatter X-rays, like other forms of electromagnetic radiation, follow the inverse square law, which states that the intensity of the energy radiating from a point source is inversely proportional to the square of the distance from an object. In English, this means that an object twice as far away only receives 1/4 the energy. Wikipedia notes that while the Earth is three times farther from the sun than Mercury, the latter planet receives nine times as much radiation. Mars is roughly four times farther from the sun than Mercury, and receives roughly 1/16 as much solar radiation.

This has direct correlation to the backscatter X-ray question and its impact on health. Much has been written about the impact of properly-tuned backscatter systems operating in airports. Backscatter systems operating in mobile vehicles are an entirely different question. How were these deployed? Did the NYPD clear the area of humans before it activated the systems? Has anyone ever walked between a backscatter system and its intended target, and what steps did the NYPD take to inform the individual of the potential risks of having done so?

These are not minor quibbles over fact-finding and the NYPD, unlike the US military, is directly beholden to the citizens of New York City, which it claims to protect. Those citizens have a right to know when the city deploys new, incredibly expensive technologies that vacuum up tax dollars and create potential health problems. That’s before we touch on the nature of such surveillance, which previous cases have established should only be used when a warrant has already been secured.

The “just trust us” defense was tired before the Snowden leaks. Two-and-half years after, it’s completely bankrupt. Time and time again, we’ve seen ample evidence that various authorities in America have abused their power, lied to judges about the nature of surveillance, and fought for the right to spy on ordinary Americans in complete disregard for such minor niceties as due process of law.