Ouch

You’ve probably heard something about it. The Pentagon’s new toy dubbed the Active Denial Technology (ADT) which according to the Sandia National Laboratory provides, “an effective non lethal active-response mechanism to disperse, disturb, distract, and establish the intent of intruders.”

The weapon, something like a weaponized microwave would be fitted to “military” vehicles and is destined for crowd control. The beam would instantly heat water beneath a target’s skin to 130 degrees Fahrenheit. It does this by emitting a 95 GHz non-ionizing electromagnetic beam of energy that penetrates approximately 1/64 of an inch into human skin tissue, where nerve receptors are concentrated. Within seconds, the beam will heat the exposed skin tissue to a level where intolerable pain is experienced and natural defense mechanisms take over.

The military and Sandia say it is safe and would have no long lasting effects.

Of course, there are those who beg to differ.

The ADS weapon's beam causes pain within 2 to 3 seconds and it becomes intolerable after less than 5 seconds. People's reflex responses to the pain is expected to force them to move out of the beam before their skin can be burnt. A report from the Columbia School of Journalism said that when the weapon was tested recently at Kirtland Air Force Research Laboratory in Albuquerque, N.M test subjects who were hit said it felt like having your entire body wrapped around a light bulb.

John Pike of think tank Globalsecurity.org fears that the beam power needed to scare people may be too close to the level that would injure them. Air Force scientists helped set the present skin safety threshold of 10 milliwatts per square centimeter in the early 1990s, when little data was available, says Louis Slesin, editor of Microwave News.

That limit covers exposure to steady fields for several minutes to an hour - but heating a layer of skin 0.3 mm thick to 50 °C in just one second requires much higher power and may pose risks to the cornea, which is more sensitive than skin. A study published last year in the journal Health Physics showed that exposure to 2 watts per square centimeter for three seconds could damage the corneas of rhesus monkeys.

Details of the ADS tests only became somewhat availabe after after Edward Hammond, director of the US Sunshine Project - an organisation campaigning against the use of biological and non-lethal weapons - requested them under the Freedom of Information Act.

In fact, volunteers who took part in the tests were, according to New Scientist, banned from wearing glasses or contact lenses during those tests due to “safety fears.” The magazine says, “The precautions raise concerns about how safe the Active Denial System (ADS) weapon would be if used in real crowd-control situations.”

In addition to the ban on eye wear, in the third of a series of tests, subjects were required to remove, “…any metallic objects such as coins and keys to stop hot spots being created on the skin. They also checked the volunteers' clothes for certain seams, buttons and zips which might also cause hot spots.”

During the experiments, people playing rioters put up their hands when hit and were given a 15-second cooling-down period before being targeted again. One person suffered a burn in a previous test when the beam was accidentally used on the wrong power setting.

Neil Davison, co-ordinator of the non-lethal weapons research project at the University of Bradford in the UK, says in New Scientist controlling the amount of radiation received may not be all that simple. "How do you ensure that the dose doesn't cross the threshold for permanent damage?" he asks. "What happens if someone in a crowd is unable, for whatever reason, to move away from the beam?"

Ouch! Sources: Mindfully.org, New Scientist, Sandia National Laboratory, Columbia School of Journalism