An iodine grenade releases purple smoke.

An iodine grenade releases purple smoke. (Photo provided by CCDC Chemical Biological Center Pyrotechnics Branch.)

Iodine Grenade Could Provide Biological Decontamination

Iodine Grenade Could Provide Biological Decontamination

By Gay Pinder

Critical to military operations is the ability to easily ensure books, papers, computers and electronics recovered by warfighters in the field are free from biological hazards. Researchers at the U.S. Army Combat Capabilities Command (CCDC) Chemical Biological Center are working on a device that could get the job done with the pull of a pin.

Amee Polk and Mike Kauzlarich are working with iodine smoke, a step along the path to developing an iodine grenade and other iodine delivery mechanisms to make the retrieval of information materials safer for the warfighter.

“When warfighters are out in the field, there’s some concern that they may be exposed to biological agents,” engineering technician Kauzlarich said.

Warfighters may carry an assortment of information materials, from papers to PCs. Before gathering those materials to return to basecamp, they would have to undergo decontamination for possible biological agents.

In cases of a biological threat, like Ebola, the typical decontamination method is to spray everything with bleach. “It’s incredibly corrosive,” Kauzlarich said. “If warfighters hope to preserve information, they need another method of decontamination that leaves the files intact. Our idea was to come up with something that they could use without destroying the files.”

“You could conceivably pull the pin on the grenade, roll it into a room or tent and shut the door and wait while the grenade does its work,” Polk described.

The idea for the iodine grenade was sparked by another study the pyrotechnics team, including Pyrotechnics Branch Chief Nino Bonavito, read about a university that was firing a shotgun primer at a thin film of metal coated with iodine in an attempt to vaporize the iodine.

By using iodine pentoxide (an iodine compound with a lot of oxygen), Polk said the team was convinced they could generate iodine more efficiently.

“We combine iodine pentoxide and a copper metal powder and apply heat to it,” Polk revealed. “This is a thermite-like reaction, where the oxygen switches from the iodine pentoxide, liberating the iodine, to the metal fuel. The oxygen then bonds with the copper and we get copper oxide.”

Free of propellants, the grenade works like a roadside safety flare or a bug bomb. Once engaged by pulling the pin, the grenade emits a purple smoke that Polk and Kauzlarich call Ravens smoke (an allusion to Baltimore’s NFL team).

“Because it vaporizes, the iodine can get into all the nooks and crannies of items in a room,” Polk said. She also said the copper oxide created in the process is a plus since copper is a natural antimicrobial, has low toxicity and is easy to clean up.

Kauzlarich points to another plus the iodine grenade provides.

“You can’t ask warfighters to jump out of an airplane in the middle of the night carrying a 55-gallon drum of bleach,” he said. “But we can give warfighters various forms of this iodine grenade to lighten their load – everything from little capsules to a grenade to a smoke pot and they could place these in a room to kill the organisms, ensuring the safety of the warfighter.”

The iodine grenade is effective against spores and vegetative cells – a cell that is not actively growing. Resistant to heat, radiation and chemicals, spores are some of the hardest life forms to kill.

“We achieved 7 log reduction – total death, complete kill,” Polk said. “It’s very difficult to break that outer shell of the spore and the fact that we were able to kill those is huge.”

Polk sees yet another advantage to the grenade. “It’s almost impossible to develop a resistance to iodine. It’s a small molecule so it penetrates the membranes of the organism and they can’t build up a resistance like they can to an antibiotic. There is no pathway for the cell to protect itself.”

Polk also sees a broader use for the grenade beyond the warfighter. She said the iodine grenade could also be used by first responders and healthcare workers in the field. “You could use it like a bug bomb and knock a biological threat down, so you don’t have to go into a contaminated site wearing level A [the highest level of personal protective equipment].”

So far, the team has tested the grenade only in the lab chamber using a 20 gram pellet. Next steps include perfecting the ratio of iodine pentoxide to metal fuel, defining contact time and testing the grenade in a larger space like a room or house.

“All the things you need money to do,” Polk said.

Armed with the Bernard E. Douda Young Scientist Award she recently received from the International Pyrotechnics Society, Polk will present the project to the Defense Advanced Research Projects Agency (DARPA) with the hope of gaining funds.

Those funds can’t come soon enough for the team.

“It’s only a matter of time until we run up against some real biological threat,” Kauzlarich warns. “A commander doesn’t want to hear about problems, he wants to hear about solutions and we’re supposed to have the solutions before the problems emerge.”

An iodine grenade releases purple smoke. (Photo provided by CCDC Chemical Biological Center Pyrotechnics Branch.)