Medical Aspects of Chemical Warfare (2008) - The Black Vault

History of the Chemical ThreatFig. 4-12. A chemical warhead for the Honest John rocket.It was designed to break apart and disperse the sphericalbomblets of nerve agent.Photograph: Courtesy of Research, Development and EngineeringCommand Historical Research and Response Team,Aberdeen Proving Ground, Maryland.to be used. Because most agents were extremely corrosive,long-term storage of unitary munitions waslogistically problematic.The idea behind binary munitions was to createnerve agent in the weapon after firing or droppingby mixing two nonlethal chemicals. The two nonlethalchemicals could be stored separately, solving theproblem of long-term storage and making handlingsafer. The Navy initially took more interest in thebinary program during the 1960s and requested a500-lb bomb designated the “Bigeye.” In the Army,however, the binary program received high priorityonly after the production of unitary chemical munitionswas halted.The M687 projectile used a standard M483A1 155-mm projectile to carry the chemical payload. Thechemical reactants were contained in two separate,plastic-lined, hermetically sealed containers. Theseleak-proof canisters were loaded through the rear ofthe shell and fitted one behind the other in the bodyof the projectile. The forward canister containedmethylphosphonic difluoride and the rear canistercontained isopropyl alcohol and isopropylaminesolution. 26,27M687 projectiles were shipped and stored withonly the forward methylphosphonic-difluoride–filledcanister in place to ensure safe handling. A fiberboardspacer occupied the cavity provided for the isopropylalcohol and isopropylamine solution canister. Projectileswere secured horizontally on a pallet, as opposedto the conventional vertical position used for otherFig. 4-13. The M139 4.5-in spherical sarin bomblet usedin the Little John rocket. The vanes on the outside of thebomblet created a spin, which armed the impact fuse. Theexplosive burster is in the center, and sarin fills the two outercompartments.Photograph: Courtesy of Research, Development and EngineeringCommand Historical Research and Response Team,Aberdeen Proving Ground, Maryland.155-mm projectiles. This orientation permitted rapidremoval of the projectile’s base with a special wrench.The fiberboard spacers were removed and replacedwith the isopropyl alcohol and isopropylamine solutioncanisters. The fuse was installed just prior to firing.Upon firing, setback and spin forces caused thefacing disks on the canisters to rupture, allowing thereactants to combine to form sarin while en route tothe target. 26,27The last open air test of lethal agents took place atDugway Proving Ground on September 16, 1969, whena 155-mm projectile filled with sarin binary reactantswas test fired. Throughout the early 1970s additionaltest firings took place using simulants. In 1976 theArmy standardized the M687 binary GB2 155-mmprojectile (Figure 4-14).In addition to the M687, the Army also worked onthe Bigeye bomb and other projectiles, including an8-in projectile. None of these was ever standardized.Standardization of the M687 did not lead immediately123