Development of a prototype dry decontamination method for particulate contamination: The DryCon system

This article describes the development of a prototype dry decontamination system (DryCon) for use in the event of a contamination incident involving a particulate contaminant. Disrobing and showering is currently recommended almost exclusively in mass decontamination, although it may not be feasible when water is scarce, in cold weather environments, or when there may be compliance issues with the requirement to disrobe, ie, unwillingness to disrobe. During disrobing, dust particles could also re-aerosolize, leading to inhalation of contaminants.

The DryCon prototype uses air jets for dry decontamination. The system is portable and can run on building-supplied 220-V power or generator power. Multiple contaminated persons can be treated rapidly, one after the other, using this system.

We tested DryCon in a controlled environment, using a manikin and three different types of fabric squares to investigate its effectiveness, with a decontamination time of 60 seconds.

At the higher airflow tested, ie, 90 percent of full blower speed or approximately 540 cfm (15 m3/minute), mean decontamination efficiencies of 56.8 percent, 70.3 percent, and 80.7 percent were measured for firefighter (FF) turnout fabric, cotton denim, and polyester double knit fabric, respectively.

Removal of this easily re-aerosolized fraction of the contaminants helps protect contaminated people, as well as healthcare providers they come in contact with, from the potential risk of further inhalation exposures from the re-aerosolization caused by doffing clothing.

The results demonstrate the promise of the DryCon system for use where water is not available, as a first step prior to wet decontamination, or in an industrial setting for post-work-shift decontamination. Further lab and field research will be necessary to prove the effectiveness of this technique in real-world applications and to determine if respiratory protection or other personal protective equipment (PPE) is needed during use of the DryCon system.