People sniffer
Encyclopedia
People sniffer was the field name for a series of U.S. Army personnel detectors used during the Vietnam War
. The purpose was to detect enemy soldiers in hidden positions, which were often employed in the jungle combat conditions of Vietnam. The U.S. military used two different versions of the people sniffer, one backpack version and one helicopter-mounted version.
s unique to human beings; such as those found in urine and sweat. The technology was developed by General Electric
for the Army's Chemical Corps. Sweat, being partially composed of ammonia
, when combined with hydrochloric acid
produces ammonium chloride
. Chemical officers planned the detection missions, later known as Operation Snoopy, while individual Chemical Corps soldiers learned how to use the detector equipment and conduct detection operations.
sent John D. Baldeschwieler to Vietnam in order to conduct controlled experiments and determine the ability of the people sniffers to detect ammonia. The tests showed that the people sniffer responded randomly to ammonia indicators, making it a very subjective instrument. Despite this, the ability of the people sniffer to detect other effluents, such as smoke, helped it to remain a valuable tool during the Vietnam War
.
The Viet Cong (VC) and the North Vietnamese Army (NVA) were able to develop effective, low-tech countermeasures to the people sniffers. The airborne sniffers soon became recognizable to the VC and NVA and they would attempt to avoid detection by not firing on Operation Snoopy missions. (Snoopy's ability to detect smoke meant it could easily locate ground troops firing with small arms, even if under cover and camouflaged.) In later Snoopy operations, the detection helicopters were disguised as gunships in order to provoke easily detectable small arms fire.
Another effective decoy used by the NVA and VC involved hanging buckets of mud with urine in trees and then moving into another area. Tactics such as these essentially rendered people sniffers ineffective in jungle terrain, but they remained useful in open areas, such as those found in the Mekong Delta
.
Vietnam War
The Vietnam War was a Cold War-era military conflict that occurred in Vietnam, Laos, and Cambodia from 1 November 1955 to the fall of Saigon on 30 April 1975. This war followed the First Indochina War and was fought between North Vietnam, supported by its communist allies, and the government of...
. The purpose was to detect enemy soldiers in hidden positions, which were often employed in the jungle combat conditions of Vietnam. The U.S. military used two different versions of the people sniffer, one backpack version and one helicopter-mounted version.
Detection method
The detection method used by people sniffers depended on effluentEffluent
Effluent is an outflowing of water or gas from a natural body of water, or from a human-made structure.Effluent is defined by the United States Environmental Protection Agency as “wastewater - treated or untreated - that flows out of a treatment plant, sewer, or industrial outfall. Generally refers...
s unique to human beings; such as those found in urine and sweat. The technology was developed by General Electric
General Electric
General Electric Company , or GE, is an American multinational conglomerate corporation incorporated in Schenectady, New York and headquartered in Fairfield, Connecticut, United States...
for the Army's Chemical Corps. Sweat, being partially composed of ammonia
Ammonia
Ammonia is a compound of nitrogen and hydrogen with the formula . It is a colourless gas with a characteristic pungent odour. Ammonia contributes significantly to the nutritional needs of terrestrial organisms by serving as a precursor to food and fertilizers. Ammonia, either directly or...
, when combined with hydrochloric acid
Hydrochloric acid
Hydrochloric acid is a solution of hydrogen chloride in water, that is a highly corrosive, strong mineral acid with many industrial uses. It is found naturally in gastric acid....
produces ammonium chloride
Ammonium chloride
Ammonium chloride NH4Cl is an inorganic compound with the formula NH4Cl. It is a white crystalline salt that is highly soluble in water. Solutions of ammonium chloride are mildly acidic. Sal ammoniac is a name of natural, mineralogical form of ammonium chloride...
. Chemical officers planned the detection missions, later known as Operation Snoopy, while individual Chemical Corps soldiers learned how to use the detector equipment and conduct detection operations.
XM-2
The XM-2 personnel detector manpack, also known as the E63 manpack personnel detector, was the first version of the people sniffer employed by the Army. The XM-2 featured a backpack mounted sensor with an air intake tube on the end of a rifle. The XM-2 was problematic in often detecting the soldier carrying it rather than the enemy. The device also made a distinct sound, easily detectable by the enemy.XM-3
The XM-3 airborne personnel detector was a helicopter mounted personnel detector and the second version of the people sniffers. The XM-3 used two independent and identical units that operated in two separate modes. In 1970, the XM-3 became the M3 personnel detector; the M3 became standard issue and was employed almost daily in LOH-6, OH-58 and UH-1 helicopters.Effectiveness
While useful, the detectors had to be used with some caution. People sniffers were known to be oversensitive and would often detect civilians or animals excreting bodily waste. In 1967 the Army Scientific Advisory PanelArmy Science Board
The Army Science Board is a Federal Advisory Committee organized under the Federal Advisory Committee Act. It is the Department of the Army senior scientific advisory body that was chartered in 1977 to replace the Army Scientific Advisory Panel...
sent John D. Baldeschwieler to Vietnam in order to conduct controlled experiments and determine the ability of the people sniffers to detect ammonia. The tests showed that the people sniffer responded randomly to ammonia indicators, making it a very subjective instrument. Despite this, the ability of the people sniffer to detect other effluents, such as smoke, helped it to remain a valuable tool during the Vietnam War
Vietnam War
The Vietnam War was a Cold War-era military conflict that occurred in Vietnam, Laos, and Cambodia from 1 November 1955 to the fall of Saigon on 30 April 1975. This war followed the First Indochina War and was fought between North Vietnam, supported by its communist allies, and the government of...
.
The Viet Cong (VC) and the North Vietnamese Army (NVA) were able to develop effective, low-tech countermeasures to the people sniffers. The airborne sniffers soon became recognizable to the VC and NVA and they would attempt to avoid detection by not firing on Operation Snoopy missions. (Snoopy's ability to detect smoke meant it could easily locate ground troops firing with small arms, even if under cover and camouflaged.) In later Snoopy operations, the detection helicopters were disguised as gunships in order to provoke easily detectable small arms fire.
Another effective decoy used by the NVA and VC involved hanging buckets of mud with urine in trees and then moving into another area. Tactics such as these essentially rendered people sniffers ineffective in jungle terrain, but they remained useful in open areas, such as those found in the Mekong Delta
Mekong Delta
The Mekong Delta is the region in southwestern Vietnam where the Mekong River approaches and empties into the sea through a network of distributaries. The Mekong delta region encompasses a large portion of southwestern Vietnam of . The size of the area covered by water depends on the season.The...
.
Further reading
- "Sniffing Out the Enemy", Time Magazine, June 9, 1967, accessed October 24, 2008.
- Vining, Mike R. "A People Sniffer Operation that Went Horribly Wrong", Army Chemical Review, Summer 2008, pp. 14–15, accessed October 24, 2008.