The M138 bomblet was a sub-munition of the U.S. chemical weapon, the M43 BZ cluster bomb. The bomblet contained BZ, an

incapacitating agent The term incapacitating agent is defined by the United States Department of Defense as: :"An agent that produces temporary physiological or mental effects, or both, which will render individuals incapable of concerted effort in the performance o ...

and was developed with the M43 in 1962. The M138s, along with all other U.S. BZ weapons were destroyed during the 1980s.

History

The U.S. Army Chemical Corps began mass-production of the chemical

M43 BZ cluster bomb The M43 BZ cluster bomb, or simply M43 cluster bomb, was a U.S. chemical cluster bomb intended to deliver the incapacitating agent known as BZ. The weapon was produced in the early 1960s and all stocks of U.S. BZ were destroyed by 1989. History ...

in March 1962.Smart, Jeffery K.
Medical Aspects of Chemical and Biological Warfare
'': Chapter 2 - History of Chemical and Biological Warfare: An American Perspective,
PDF
: p. 51), ''

Borden Institute The Borden Institute is a U.S. Army “Center of Excellence in Military Medical Research and Education”. In 1987, U.S. Army Colonel Russ Zajtchuk conceived the idea for a “Center of Excellence in Military Medical Research and Education,” u ...

'', Textbooks of Military Medicine, PDF via

Maxwell-Gunter Air Force Base Maxwell Air Force Base , officially known as Maxwell-Gunter Air Force Base, is a United States Air Force (USAF) installation under the Air Education and Training Command (AETC). The installation is located in Montgomery, Alabama, United States. O ...

, accessed December 11, 2008.Davison, Neil.
'Off the Rocker' and 'On the Floor': The Continued Development of Biochemical Incapacitating Weapons
", Bradford Science and Technology Report No. 8, Department of Peace Studies,

University of Bradford The University of Bradford is a public research university located in the city of Bradford, West Yorkshire, England. A plate glass university, it received its royal charter in 1966, making it the 40th university to be created in Britain, but ...

(UK), August 2007, p. 5, accessed December 11, 2008. The M43 was designed to utilize the M138 bomblet. The M138, like its parent cluster bomb and all BZ munitions, were stored at

Pine Bluff Arsenal The Pine Bluff Arsenal is a United States Army installation in Jefferson County, Arkansas, about eight miles northwest of Pine Bluff and thirty miles southeast of Little Rock. Pine Bluff Arsenal is one of nine Army installations in the United ...

in Arkansas. Between 1988 and 1989 all U.S. BZ munitions, including the M138 bomblets were demilitarized and destroyed.Mauroni, Albert J. ''Chemical Demilitarization: Public Policy Aspects'',
Google Books
, Greenwood Publishing Group, 2003, p. 19, ().

Specifications

The M138 bomblet had the largest continuous diameter of any chemical bomblet in the U.S. arsenal, a full 72 millimeters (mm).Trott, p. 1 The M138 also possessed the thickest steel walls of U.S. bomblets, about 3 mm. The M43 cluster bomb was designed to hold 57 M138s, arranged in three stacks of 19 bomblets. Each bomblet held about of the

BZ, also known as

3-Quinuclidinyl benzilate 3-Quinuclidinyl benzilate (QNB) (IUPAC name 1-azabicyclo .2.2ctan-3-yl hydroxy(diphenyl)acetate; US Army code EA-2277; NATO code BZ; Soviet code Substance 78) is an odorless and bitter-tasting military incapacitating agent.QNB: Incapacitating Age ...

. The bomblets themselves were composed of M7 canisters which held a 50/50 mixture of pyrotechnic and agent (pyromix).Trott, p. 70 Each bomblet was a thin-walled cylinder that held an M150A2 "all-ways" acting impact fuze with an M308 delay element. The M138 became armed immediately upon separating from the M43 cluster bomb and its M30 cluster adapter. When the bomblet impacted the ground it ignited the fuze, and, after a short delay, the pyromix was ignited.

Tests involving the M138

The M138 was the subject of various tests, including those to determine its effectiveness and its detonability as demilitarization plans for BZ weapons ramped up during the 1980s. Tests undertaken at Pine Bluff Arsenal in 1981 showed that the M138 was a non-detonable item.Trott, p.57 Because of these test results it was determined that any demilitarization plant need not include provisions for the containment of accidental detonation of the M138. Regardless, an Army report issued on the results of the testing emphasized that extreme care must be exercised in order to prevent accidental detonation of the M138 bomblets as they were destroyed. Other testing of the M138 was carried out by the U.S. Army's Deseret Test Center under the auspices of

Project 112 Project 112 was a biological and chemical weapon experimentation project conducted by the United States Department of Defense from 1962 to 1973. The project started under John F. Kennedy's administration, and was authorized by his Secretary ...

.Project 112/SHAD Fact Sheets
", Force Health Protection & Readiness Policy & Programs, The Chemical-Biological Warfare Exposures Site, accessed December 11, 2008. These tests, known collectively as "Tall Timber" were carried out from April through June 1966 at the Waiakea Forest Reserve near Hilo,

Hawaii Hawaii ( ; haw, Hawaii or ) is a state in the Western United States, located in the Pacific Ocean about from the U.S. mainland. It is the only U.S. state outside North America, the only state that is an archipelago, and the only state ...

. The purpose of the Tall Timber tests was to determine the effectiveness of BZ-filled M138 bomblets in a

tropical forest Tropical forests (a.k.a. jungle) are forested landscapes in tropical regions: ''i.e.'' land areas approximately bounded by the tropic of Cancer and Capricorn, but possibly affected by other factors such as prevailing winds. Some tropical fore ...

environment. The tests used statically ignited M138 bomblets containing live BZ incapacitating agent.Fact Sheet — Tall Timber
", ''Office of the Assistant Secretary of Defense (Health Affairs)'', Deployment Health Support Directorate, accessed December 11, 2008.

History

Specifications

Tests involving the M138

See also

Notes

Further reading