After a lengthy test phase, the U.S. Army has decided that it will not use one of its most tested non-lethal weapons:  the ADS.

The story of the ADS begins with the U.S. Military's interest in creating non-lethal solutions to disperse angry crowds and other hostile parties.  From sonic weapons to strobe lights, many exotic solutions have been tried, though none have been broadly embraced by the U.S. armed forces.

Among the most intriguing non-lethal weapons was the Humvee-mounted "pain ray" cannon, a 95 GHz microwave heat ray formally known as the Active Denial System (ADS).  The device, which has a range of 500 meters, was manufactured by Communications and Power Industries (CPI), a Palo Alto, California-based defense contractor.

The ray was supposedly safe, creating a sensation of intense burning and pain.  As the waves were of higher frequency than those of a typical food microwave oven (2.45 GHz) they only penetrated 1/64 of an inch into the skin, lowering the risk of tissue damage or cancer.  While there were concerns about long term effects of exposures, the ray was purportedly safe.

CPI was awarded a $6.4M USD contract in 2004 to produce two of the weapons, and by 2007 had a working product.  After reportedly being considered in 2006 for an Iraq deployment, the device was finally shipped to Afghanistan in 2010 for field testing.

The ray was tested 11,000 times on over 700 people, including a Reuters journalist, who commented, "Similar to a blast from a very hot oven – too painful to bear without diving for cover."

Despite relative success, the BBC News is reporting that the U.S. armed forces leadership has confirmed that the device has been shipped out of Afghanistan and will not see its first official action in the field.

Colonel Shanks, Chief of Public Affairs for ISAF comments, "The ADS was not used and was shipped from Afghanistan. The operational need for the device was not approved by commanders."

No specific reason was given for the decision to pull the device.

Even if that spells the end for the cannon prototype, the device may live on in a smaller version of the ADS, the Silent Guardian.  Defense contractor Raytheon is working on the device which it looks to market to law enforcement agencies in the U.S. and abroad.  The joystick-aimed cannon has a range of 550 meters.  Raytheon also looks to market the device to the military.