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


  • Barbara M. Alexander, PhD, PE, CIH
  • H. Amy Feng, MS
  • Gabriel Merk, BS



decontamination, air shower, emergency response, engineering control, particulate


Objective: 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.

Design: 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.

Setting: 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.

Main outcome: 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.

Results: 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.

Conclusion: 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.

Author Biographies

Barbara M. Alexander, PhD, PE, CIH

Senior Service Fellow, Division of Field Studies and Engineering, Engineering and Physical Hazards Branch, National Institute for Occupational Safety and Health, Cincinnati, Ohio

H. Amy Feng, MS

Statistician, Division of Field Studies and Engineering, Engineering and Physical Hazards Branch, National Institute for Occupational Safety and Health, Cincinnati, Ohio

Gabriel Merk, BS

ORISE Fellow, Division of Field Studies and Engineering, Engineering and Physical Hazards Branch, National Institute for Occupational Safety and Health, National Institute for Occupational Safety and Health, Cincinnati, Ohio


Fitzgerald GJ: Chemical warfare and medical response during World War I. Am. J. Pub. Health. 2008; 98(4): 611-625.

Lake W, Schulze P, Gougelet R, et al.: Guidelines for mass casualty decontamination during an HAZMAT/weapon of mass destruction incident: Volumes I and II. Ft. Leonard Wood, MO 2013.

U.S. Departments of Homeland Security and Health and Human Services: Patient Decontamination in a Mass Chemical Exposure Incident: National Planning Guidance for Communities 2014.

Chilcott RP, Larner J, Matar H: Primary Response Incident Scene Management: PRISM Guidance, Volume 1, Second Edition. Primary Response Incident Scene Management (PRISM): Guidance for the Operational Response to Chemical Incidents 2018.

Cibulsky SM, Sokolowski D, Lafontaine M, et al.: mass casualty decontamination in a chemical or radiological/nuclear incident with external contamination: Guiding principles and research needs. PLoS Curr. 2015; 7.

Matar H, Price SC, Chilcott RP: Temporal effects of disrobing on the skin absorption of chemical warfare agents and CW agent simulants. Toxicology. 2010; 278(3): 344-345.

Carter H, Drury J, Rubin GJ, et al.: Public experiences of mass casualty decontamination. Biosecur Bioterror. 2012; 10(3): 280-289.

USFA: Fire department response to biological threat at B’nai B’rith Headquarters, Washington, DC: USFA. Report No. USFA-TR-114 1997.

Carter H, Amlôt R, Williams R, et al.: Mass casualty decontamination in a chemical or radiological/nuclear incident: Further guiding principles. PLoS Curr. 2016; 8: ecurrents.dis.569a583b893759346e893759511a893759070cb893759900d893759352.

McDonagh A, Byrne MA: The influence of human physical activity and contaminated clothing type on particle resuspension. J Environ Radioact. 2014; 127: 119-126.

Layshock JA, Pearson B, Crockett K, et al.: Reaerosolization of Bacillus spp. in outdoor environments: A review of the experimental literature. Biosecur Bioterror. 2012; 10(3): 299-303.

Byers RJ, Medley SR, Dickens ML, et al.: Transfer and reaerosolization of biological contaminant following field technician servicing of an aerosol sampler. J Bioterrorism Biodefense. 2013; S3(011): 1-8.

Power S, Symons C, Carter H, et al.: Mass casualty decontamination in the United States: An online survey of current practice. Health Secur. 2016; 14(4): 226-236.

Chilcott RP: Managing mass casualties and decontamination. Environ Int. 2014; 72: 37-45.

Amlôt R, Carter H, Riddle L, et al.: Volunteer trials of a novel improvised dry decontamination protocol for use during mass casualty incidents as part of the UK’S Initial Operational Response (IOR). PLoS One. 2017; 12(6): e0179309.

Josse D, Wartelle J, Cruz C: Showering effectiveness for human hair decontamination of the nerve agent VX. Chem Biol Interact. 2015; 232: 94-100.

Matar H, Guerreiro A, Piletsky SA, et al.: Preliminary evaluation of military, commercial and novel skin decontamination products against a chemical warfare agent simulant (methyl salicylate). Cutan Ocul Toxicol. 2016; 35(2): 137-144.

Roul A, Le C-A-K, Gustin M-P, et al.: Comparison of four different fuller’s earth formulations in skin decontamination. J Appl Toxicol. 2017; 37(12): 1527-1536.

Chilcott RP, Larner J, Durrant A, et al.: Evaluation of US Federal Guidelines (Primary Response Incident Scene Management [PRISM]) for mass decontamination of casualties during the initial operational response to a chemical incident. Ann Emerg Med. 2019; 73(6): 671-684.

Ranade MB: Adhesion and removal of fine particles on surfaces. Aerosol Sci Technol. 1987; 7(2): 161-176.

Fletcher R, Briggs N, Ferguson E, et al.: Measurements of air jet removal efficiencies of spherical particles from cloth and planar surfaces. Aerosol Sci Technol. 2008; 42(12): 1052-1061.

Ziskind G, Fichman M, Gutfinger C: Resuspension of particulates from surfaces to turbulent flows—Review and analysis. J Aerosol Sci. 1995; 26(4): 613-644.

Ibrahim AH, Dunn PF, Brach RM: Microparticle detachment from surfaces exposed to turbulent air flow: Effects of flow and particle deposition characteristics. J Aerosol Sci. 2004; 35(7): 805-821.

Ibrahim AH, Dunn PF, Qazi MF: Experiments and validation of a model for microparticle detachment from a surface by turbulent air flow. J Aerosol Sci. 2008; 39(8): 645-656.

Phares DJ, Smedley GT, Flagan RC: Effect of particle size and material properties on aerodynamic resuspension from surfaces. J Aerosol Sci. 2000; 31(11): 1335-1353.

Harris AR, Davidson CI: Particle resuspension in turbulent flow: A stochastic model for individual soil grains. Aerosol Sci Technol. 2008; 42(8): 613-628.

Smedley GT, Phares DJ, Flagan RC: Entrainment of fine particles from surfaces by gas jets impinging at normal incidence. Exp Fluids. 1999; 26: 324-334.

Pollock DE, Cecala AB, Zimmer JA, et al.: A new method to clean dust from soiled work clothes. presented at: 11th U.S./North American Mine Ventilation Symposium: 2006.

Cecala AB, Pollock DE, Zimmer JA, et al.: Reducing dust exposure from contaminated work clothing with a stand-alone cleaning system. 12th U.S./North American Mine Ventilation Symposium 2008. Reno, Nevada: 2008.

Alexander BM, Baxter CS: Flame retardant contamination of firefighter personal protective clothing—A potential health risk for firefighters. J Occup Environ Hygiene. 2016; 13(9): D148-D155.

Fent KW, Alexander B, Roberts J, et al.: Contamination of firefighter personal protective equipment and skin and the effectiveness of decontamination procedures. J Occup Environ Hygiene. 2017; 14(10): 801-814.

NIOSH: Rapid dry field decontamination method for firefighters. Engineering research report. Cincinnati, Ohio: U.S. Department of Health and Human Services, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health; 2017.

Loughran TM, Shea MJ: The effectiveness of air showers in the contamination control process; 1996. Available at Accessed October 19, 2020.

Tsepelev AV: Evaluating the efficiency of air shower in removing lead from army combat uniform swatches loaded with gunshot residue. Bethesda, Maryland: Uniformed Services University of the Health Sciences; 2016.

Slagley JM, Paschold H, Engler JM: Evaluation of coverall field dry aerosol decontamination methods using a manikin. J Occup Environ Hygiene. 2017; 14(7): 502-509.

NIOSH: Demonstrations of Control Technology for Secondary Lead Reprocessing. Volume 2. Cincinnati, Ohio: U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health; 1983.

Mukai C, Siegel JA, Novoselac A: Impact of airflow characteristics on particle resuspension from indoor surfaces. Aerosol Sci Technol. 2009; 43(10): 1022-1032.

McDonagh A, Byrne MA: A study of the size distribution of aerosol particles resuspended from clothing surfaces. J Aerosol Sci. 2014; 75(Suppl. C): 94-103.

Kesavan J, Humphreys P, Nasr B, et al.: Experimental and computational study of reaerosolization of 1 to 5 μm PSL microspheres using jet impingement. Aerosol Sci Technol. 2017; 51(3): 377-387.



How to Cite

Alexander, PhD, PE, CIH, B. M., H. A. Feng, MS, and G. Merk, BS. “Development of a Prototype Dry Decontamination Method for Particulate Contamination: The DryCon System”. American Journal of Disaster Medicine, vol. 15, no. 4, Oct. 2020, pp. 261-73, doi:10.5055/ajdm.2020.0375.