Preparedness

SNL and Merlin: A New Way to Look at Decontamination

by Rob Schnepp
By Rob Schnepp, rschnepp@domprep.com

In 1997, the Department of Energy (DOE) received a mandate from Congress to develop improved technologies for use in the “Global War on Terrorism.” One purpose of that mandate was to find a more effective way to decontaminate (decon) potential biological and chemical agents – in other words, something better than the traditional water-based decontamination agents employed by most fire agencies at the time.

Fast-forward to the New Mexico desert, home of the Sandia National Laboratory (SNL), where a new decontamination solution, DF100, was developed as an initial response to the mandate. A peroxide-based foam solution, DF100 proved to be quite effective at rapidly deactivating nerve agents as well as destroying all conventional biological pathogens considered to pose a credible threat.

Fast-forward again to the current version of the SNL solution, called DF200. “Right now, it’s the top dog in decon,” said Dennis Smagac, founder and director of business development at Intelagard Inc., a company based in Broomfield, Colorado. “The U.S. military and the Capitol Hill police are using Intelagard’s Merlin™ system, a compressed-air foam delivery system, with DF200 as the decon solution,” Smagac said. “It’s a very efficient combination. It’s mobile, and not dependent on having water available.” DOE has licensed two companies to manufacture the SNL solution, Smagac said: Modec, in Denver; and Envirofoam Technologies in Huntsville, Alabama.

“Spectacularly Effective” – Fast, Too Intelagard specializes in the design of compressed-air foam (CAF) systems for the deployment of liquid-based solutions, like the SNL DF200 solution, and various firefighting and hazardous materials foam concentrations. It was Intelagard’s Merlin CAF system, using DF200 that was used to clean the U.S. Senate office buildings that were discovered, not long after the 9/11 terrorist attacks, to be contaminated with anthrax.

The SNL formulation is spectacularly effective at deactivating chemical warfare (CW) agents, biological pathogens, and many toxic industrial chemicals (TICs). In studies conducted by Envirofoam and the U.S. military, DF200 achieved a 99 percent neutralization rate against nerve agents such as soman (GD) and VX, with a 15-minute contact time. Within one hour, the nerve agents were completely destroyed, without the formation of any toxic byproducts. Sulfur mustard was broken down with equal effectiveness, and many TICs – including sodium cyanide, butyl isocyanate, carbon disulfide, phosgene (gas), chlorine (gas), and anhydrous ammonia (gas) – were 99 percent neutralized within one minute of contact time with SNL DF200.

DF200 also proved to be a highly effective decontamination agent against biological warfare agents when tested against simulants for anthrax and plague, achieving a “7-log” kill – i.e., 99.99999 percent – within 15 minutes of contact time (further testing on live warfare agents confirmed the effectives proven on the simulants). The Bovine Corona Virus, a surrogate for Severe Acute Respiratory Syndrome, aka the SARS virus, was successfully inactivated after a one-minute exposure to a 10 percent concentration of SNL DF200. (For additional information on technical specifications of the DF200 foam solution, visit www.sandia.gov/SandiaDecon/.)

“DF200 can be applied in any fashion and still be effective,” according to Mark Tucker, technical contact at Sandia National Laboratory. “The solution may be applied through compressed-air foam systems, or as a liquid in a paint sprayer or even a bug sprayer.

“The purpose of using DF200 is two-fold,” he added. “It’s intended to be used for remediation efforts [e.g., the decontamination work at the U.S. Senate buildings], or for decon.”

Environmentally Friendly, and Approved by EPA When the DF200 is applied through a CAF system such as Merlin, the resulting foam enhances the contact time between the decon solution and the substance. Contact time is a critical factor in deactivating or neutralizing the hazard. “Essentially,” Tucker said, “the foam holds the agent, and the peroxide, which is a little stronger than what you have at home, breaks the chemical bonds. To activate the foam solution, a surfactant, a fortifier, and a booster are mixed inside a five-gallon bucket. Once the components are mixed, the foam solution is ready to go – with about an eight-hour pot life.” Figure #1 shows a bucket of DF200 foam solution.

DF 200 also has been proved to have no compatibility issues with materials such as wood, paper, plastic, concrete, or asphalt–typical construction materials found at hazardous materials incident sites. But it may, according to Tucker, be mildly corrosive to ferrous materials such as iron and steel.

“The SNL DF200,” Smagac said, “Is environmentally friendly, and has received approval from the U.S. Environmental Protection Agency for use on chem/bio agents.” Figure #2 displays the partial components of the DF200 decon solution.

The Merlin system, along with the SNL DF200 foam solution, is used by all Federal Emergency Management Agency-sponsored urban search and rescue teams in the United States. The combination is an effective one, allowing both for portability and for rapid decon in the field–important advantages when a team is operating in potential collapse areas and/or in other places where water may not be available. The Merlin, seen in figure #3 during a training exercise, functions as a fully independent handcart, capable of delivering a variety of liquids from twin 7.5-gallon tanks.

When dispensing foam, the Merlin has the ability to expand the DF200, or standard firefighting foams, in ratios ranging from 1:1 all the way up to 70:1, depending on the type of foam used and the configuration of the nozzle. High-pressure self-contained breathing apparatus cylinders provide the “power” that makes the Merlin a truly portable compressed-air foam-dispersal system. Figure #4 shows an example of DF200 training foam being applied through a foam aspirator nozzle.

For additional information about compressed-air foam solutions and the Merlin system, visit Intelagard