Scientists from the US Army's Edgewood Chemical Biological Center (ECBC) are developing new smokescreen compositions to help soldiers effectively mask themselves from enemy fire.
Developed under a multi-year programme, the new formula is expected to replace the army's World War II-era MP-2S-HC screening smoke grenade, which delivers a dense cloud of grey hexachloroethane smoke with a discharge time of 100 seconds.
The scientists are currently considering four basic smoke compositions, the first of which is a zinc-free composition, HX, which is similar to the hexachloroethane composition but doesn't generate a toxic, irritant smoke containing zinc chloride.
ECBC Pyrotechnics and Explosives Branch senior engineer Joseph Domanico said the chemical reaction of the HX composition produces slightly less combustion products and has a higher efficiency, which results in a similarly dense smoke cloud.
"This combination makes it the most exciting smoke composition in a long while," Domanico said.
The second hexachloroethane-free composition encapsulates chlorine atoms in a plastic matrix, which are subsequently freed by the heat of combustion, enabling the smoke to pull water from the atmosphere, thus producing a dense smoke cloud.
Commenting on the second composition Domanico added: "The advantage of this composition is that none of the ingredients are water soluble, and that nearly eliminates the contamination of water supplies."
A solid solution of magnesium and aluminium capable of producing a large quantity of metal oxides as its main smoke component is the third candidate, while the last is a lithium-combustion technology composition.
Designed to easily blend in a binder, or in any other suitable mixing system, the third composition can be used in grenades, short-range mortars and even in long-range artillery, to help soldiers maintain suitable distances from their targets.
All compositions are scheduled to undergo testing and evaluations in combat conditions, including cold to hot environments and forest, desert and urban terrains, before becoming the army's smoke composition of choice for the next century.
The army is expected to consider performance, manufacturing cost, toxicity, environmental impact and the availability of materials while selecting the final composition.
Image: The US Army ECBC's Pyrotechnics and Explosives Branch detonates a HX smoke test grenade to evaluate its composition at an undisclosed location. Photo: courtesy of the US Army.