Modern technology may be working to keep us safe, but many wonder where the line between safety and privacy lands these days.  New technology allows airport security screeners to peak under your clothes and the same x-ray technology is being used by new roving vehicles looking through the exteriors of vehicles and buildings.  American Science & Engineering, a company based in Billerica, Mass., has reportedly sold U.S. and foreign government agencies hundreds of these backscatter x-ray scanners mounted in mobile vans.

While the biggest buyer of AS&E’s machines over the last seven years has been the Department of Defense for security operations in Afghanistan and Iraq, Joe Reiss, the company’s vice president of marketing, reports to Forbes that law enforcement agencies have also used the vehicles to investigate terrorist threats within the U.S.

The Z Backscatter Vans, or ZBVs, as the company calls them, bounce a narrow stream of x-rays off and through nearby objects, and read which ones come back. Absorbed rays indicate dense material such as steel. Scattered rays indicate less-dense objects that can include explosives, drugs, or human bodies. That capability makes them powerful tools for security, law enforcement, and border control.

As Forbes‘ Andy Greenberg notes, this is the same technology that has privacy advocates challenging the use of full-body scanners in the nation’s airports.

On his radio program this morning, conservative host Glenn Beck spoke with Rep. Jason Chaffetz, R-Utah, about the privacy implications of this developing technology and government’s role in utilizing it:

As a lawmaker on the Oversight and Government Reform Committee, I’ve been trying to get the administration, I’ve been trying to get the company to tell me who’s buying these vans? What are you doing with these vans?  There are some legitimate uses.  I mean, if you’re going to inspect cargo coming out of a port, I buy that. [...]

I want us to be as safe and secure as possible, but I’m not willing to give up every bit of liberty that I have.  And I fundamentally at my core just don’t trust the federal government.  They have been elusive — and I’m being generous — elusive in their answers to my questions.  … They will not confirm whether they’re just using them at the ports or just overseas. …

Click here to watch the full conversation (via RightScoop).