The events of September 11, 2001 and the anthrax contamination of government buildings have brought home to us the possibility of other terrorist attacks on public places. One specific concern is a terrorist attack on a government building, museum or other place where historic documents, photographs, artwork or other national heirlooms could be contaminated with bioagents.
The TSWG Atmospheric Plasma Decontamination Project
APP was contracted by the Technical Services Working Group, an agency of the U.S. Government, to investigate the use of the prototype Atmospheric Plasma Decontamination (APD) System as a stand-alone unit for the rapid decontamination of these highly valued items following a terrorist attack. APP validated the unit's efficacy against bacterial endospores using the AOAC Sporicidal Activity Test-Official Method 966.04. The EPA requires the use of this test as a benchmark to assess the performance of decontamination systems against bioagents like Bacillus anthracis endospores. APP also measured physical effects of the plasma on a range of materials similar to items of concern (documents, art, etc.). While an effective decontamination method, the APD has little effect on the physical properties (color, flexibility, etc) of many materials, unlike other decontamination methods that would irreparably discolor documents, for example.
Figure 2. The APD test stand.
Tests were conducted using the APD test stand shown in Figure 2. The glove box (center of photo) is used to prevent accidental biocontamination of samples from mold spores or other common airborne microorganisms. The APD itself is visible as the glowing purple cylinder to the left of center. Air is pumped into the plasma, and the exhaust from the plasma is used to treat the samples which are contained in a sample holder that is visible just above the 2nd glove port from the left. Once treated, the samples are transferred to the right half of the glove box for microbiological processing.
Materials that are ruined by standard decontamination processes showed little effects due to decontamination by APD. Examples - cotton tapestry and color laser-printed copy paper.
Figure 3. A tapestry shown before (left) and after (right) APD treatment.
Figure 4. Laser printed copy paper. The larger blocks are untreated,while the smaller blocks have been decontaminated using the APD system.
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