Chemists working for the U.S. Armed Forces report that a new hydrogen peroxide-based decontaminant has proved highly effective against a wide range of weapons of mass destruction, ranging from chemical agents to anthrax and radioisotopes.
What’s more, the decontaminant can be used at very low temperatures and is made of generally benign substances that can be absorbed harmlessly into the environment.
The hydrogen peroxide-based decontaminant, Decon Green, was tested for effectiveness against chemical agents VX, soman, and HD, the chemical of mustard gas; the biological agent anthrax; and two radiological isotopes cesium-137 and cobalt-60.
Ten authors, led by George W. Wagner of the U.S. Army Edgewood Chemical Biological Center at Aberdeen Proving Ground, Md., published their findings in the April 7 issue of the American Chemical Society's journal Industrial Engineering and Chemistry Research. They reached a conclusion that “hydrogen peroxide-based decontaminants such as Decon Green exhibit broad-spectrum efficacy for not only chemical and biological agent decontamination, but also radiological isotope removal, thus, providing for potential radiological/nuclear mitigation as well.”
The co-authors included two of Wagner’s colleagues at the Edgewood Chemical Biological Center, as well as researchers from the Naval Surface Warfare Center in Dahlgren, Va.; the U.S. Army Cold Regions Research and Engineering Laboratory in Hanover, N.H., and Pacific Northwest National Laboratory in Richland, Wash.
Decon Green was developed a few years ago as an environmentally friendly alternative to other decontaminants. Wagner was the principal inventor, and various iterations of Decon Green have been available since 2003, he said.
The authors of the paper say that the material uses only ingredients that are environmentally friendly and many are edible. It is designed to leave no lingering hazards in the environment and also, when it is used properly, to pose no toxic threat to people.
According to the paper, chlorine bleach-based decontaminants, for instance, react with the blistering agent HD to create undesirable byproducts. Some are carcinogenic, and other byproducts, even after reacting with the decontaminant, can still raise blisters.
Hydrogen peroxide serves many purposes. A familiar form is in a solution used on wounds as a disinfectant. It is used in toothpaste to whiten teeth. The concentrations of hydrogen peroxide in solutions for those purposes range from 1.5 to 3 percent. A 10 percent concentration of the chemical, however, can cause irritation to skin and even blistering.
Decon Green is 35 percent hydrogen peroxide, a common industrial concentration with a freezing point of -33 °C. It is readily available and inexpensive, and it can be used in cold weather without freezing. The authors tested the decontaminant at -32 °C and found it effective on simulants of VX and HD.
The ingredients in Decon Green include propylene glycol, which is used in cough syrup, and propylene carbonate, which is found in cosmetics. Three other ingredients are food additives: potassium citrate, which is also sold as a remedy for kidney stones; bicarbonate, and molybdate, which is used in energy bars. The only part of Decon Green that is not approved for internal or external use is the surfactant Triton X-100, which is biodegradable.
Left exposed to the atmosphere, hydrogen peroxide, H2O2, breaks down into water and oxygen.
The decontaminant was designed for treating heavy vehicles and equipment after they have been exposed to chemical, biological, radioactive, or nuclear materials. Abbreviated “CBRN,” they are the weapons of mass destruction.
Tests were conducted on materials found in vehicles: Glass, rubber, steel, aluminum, and aluminum panels painted with chemical agent resistant coating, which is common on U.S. military equipment.
In uses against chemical and biological agents, Decon Green frequently outperformed conventional treatments. In the killing of anthrax spores, where an older and a newer version of Decon Green were tested against bleach, the results were a virtual tie. Contamination was undetectable on glass slides 15 minutes after decontamination, and also undetectable in fluid suspension an hour after treatment.
Tests of effectiveness on chemical agents included trials conducted on panels of unpainted aluminum and panels with chemical agent resistant coating. A piece of latex film was laid onto the surface for fifteen minutes directly after decontamination and then at 45 through 60 minutes after decontamination. The contact test simulates a human hand resting on the treated surface. A chemical solution was used to remove the residue of the toxic agent for measuring after the contact tests.
The surfaces were contaminated with 1,000 micrograms of an agent per square centimeter. The coated surfaces were more resistant to decontamination. For VX, total decontamination was 94.1 percent on the coated panel and 99.997 on the untreated aluminum.
HD appeared to be more efficient than the other agents at penetrating the coating. After an hour, decontamination of the coated surface had reduced the blister agent by 79 percent.
According to Wagner, these results are superior to previously observed results using conventional decontaminants. Those results were not specified in the paper.
Decon Green was compared to water as a control in removing radioisotopes for various vehicle materials. On two surfaces—steel and rubber—the hydrogen peroxide-based decontaminant clearly outperformed water in removing cobalt-60. After 15 minutes of decontamination time, Decon Green had removed about 97 percent of the isotope from rubber and 48 percent from steel. Water was able to remove 66 percent from rubber and 7.7 percent from steel in the same time.
In removing cesium-137, however, Decon Green performed no better than the control using plain water.
A dry version called Decon Green Zero (that is, zero liquids) was created using two solid compounds, peracetyl borate and Peroxydone. It can be reconstituted as a liquid by the addition of propylene glycol and water for use at sub-zero temperatures, or with water for use at temperatures above freezing. The dry version has the advantage of being lighter and more compact than a liquid, and therefore more conveniently portable. The testing described in the paper indicates that there is a tradeoff in effectiveness.
It was tested in comparison to an all-weather version of Decon Green, and mixed with a 50-50 mixture of propylene glycol and water. The propylene glycol and water mixture was used by itself as a control. Because the low-temperature facilities were not designed for the use of toxic agents, the tests substituted common simulants for VX and HD.
The all-weather formula reduced the VX simulant by 87.1 percent and the HD simulant by 72.5 percent. Results for Decon Green Zero were 82.1 percent and 65.5 percent respectively. The control reduced the VX simulant by 76.6 percent and the HD substitute by 48.8 percent
The paper, “All-Weather Hydrogen Peroxide-Based Decontamination of CBRN Contaminants,” was published in the April 7 issue of the American Chemical Society journal Industrial Engineering and Chemistry Research.