Personnel Decontamination Line Sprayer Options for
Biological Contamination Incident Response
PURPOSE
To provide EPA responders information on conventional and innovative methods for conducting
personnel decontamination during a Bacillus anthracis (Ba) or other biological agent response. This brief
summarizes comparison studies (coupon and manikin) of two different types of sprayers for use in the
personnel decontamination (decon) line.
SUMMARY
This Technical Brief summarizes two studies (large coupon testing [1] and manikin testing [2]) that
compared the efficacy and performance of electrostatic sprayers (ESSs) and conventional backpack
sprayers (CBSs) for personnel decontamination in a decon line.
Both sprayer types performed well in the PRE decontamination efficacy studies, as liquid and aerosol
inoculation of a Bo surrogate onto PPE were evaluated. Operational parameters of the sprayers were
also assessed. Table 1 provides a summary and comparison of both sprayers as used in these studies.
Table 1. Decon Line Sprayer Comparison
Conventional Backpack Sprayer (CBS)
Electrostatic Sprayer (ESS)
Efficacy*
>6 log reduction
>6 log reduction
Spray Rate
996 rriL/min
62 mL/min
Aqueous Spray Volume
~2000 mL
~250 mL (with 2X spray duration)
Waste Generated
450 mL (coupon)
6 mL (coupon)
PPE Coverage Spray Duration
2 minutes (manikin)
4 minutes (manikin)
Liquid Runoff
1 Liter (manikin)
Minimal; not quantifiable (manikin)
Reaerosolization During Spray
1X 104 CFU (manikin aerosol inoculation)
2.8 X 101 CFU (manikin aerosol inoculation)
*Decontamination efficacy was calculated in terms of the log reduction (LR). An efficacy benchmark of 6 LR was used to
distinguish between effective and ineffective decontamination approaches.
CFU = colony forming units
INTRODUCTION
The personnel decon line, established in the contamination reduction zone (CRZ) following a biological
incident, is essential for ensuring that potential contamination from workers' personal protective
equipment (PPE) does not migrate outside this zone. Conventional decon procedures can lead to the
physical removal of biological contaminants, but copious amounts of decontaminant solution are often
used, leading to large volumes of aqueous-based waste.
CBSs frequently used in decon lines, have the potential to generate a significant quantity of aqueous-
based waste due to the volume of decontaminant sprayed and runoff liquid from PPE, following multiple
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entry teams moving through the decon line. Additionally, these sprayers may cause liquid splash-off
when spraying PPE surfaces, which could lead to reaerosolization. It has been demonstrated in a previous
decon line study [3] with fluorescent tracer particles, that a CBS in conjunction with scrub brushes led to
contamination spread outside the CRZ. This contamination spread was minimized by the elimination of
the scrub brush process and the use of a misting nozzle on the decontaminant sprayer. However, runoff
liquid volume and reaerosolization were not measured.
As a continuing effort to improve and optimize biological decon line procedures, recent EPA research
efforts have been conducted to determine if portable ESSs are feasible alternatives to conventional
sprayers used by the emergency response community. ESSs have been used for decades in various
industries such as agriculture, automotive industries, and healthcare because of their uniform surface
coverage characteristics [4]. More recently, ESSs have been used for personnel decontamination in
emergency responder decon lines, though their use has not been thoroughly evaluated.
Both studies summarized here used the same biological surrogate, sprayers and aqueous-based
decontamination solutions [dilute bleach (1 in 10 diluted with water)] as described below.
DECONTAMINATION MATERIALS
Sprayers Tested
The two sprayers shown in Figure 1 were tested on PPE-covered
coupons and manikins dressed in PPE.
The electric backpack sprayer (Figure 1A) is approximately 36
inches (in) high by 24 in wide by 6 in long. This CBS has a variable
speed pump, an adjustable spray cone nozzle, a 4-gallon
capacity, and a hose made of reinforced/braided polyvinyl
chloride (PVC). This sprayer has been used in previous EPA
decontamination studies and is representative of the type of
conventional handheld sprayer nozzle typically used in personnel
decon lines.
The ESS (Figure IB) is approximately 22 in high by 16 in wide by
10 in long and produces smaller electrically charged spray
droplets that are carried to the target in a gentle low-pressure
air stream. The sprayer tank has a capacity of 1 gallon and a spray
gun with hose length of 15 feet (ft). The sprayer also is equipped
with a patented MaxCharge™ technology electrostatic spray gun
that delivers droplets with a volume median diameter (VMD) of
40 micrometers (|am) [5].
Decontaminant
The decontamination agent used in the sprayers consisted of 10% diluted bleach (DB) as referenced in
the EPA Consequence Management Advisory Division's "BioResponse Decontamination Line Standard
Operating Protocol" (SOP) [6]. The solution was prepared in fresh 1-liter batches on each test day.
Neutralizing agents were used to stop the decontamination reaction to achieve a prescribed contact
time of 5 minutes as specified in the SOP.
(A)
SHURFlo 4 ProPack
Rechargeable Electric
Back Pack Sprayer SRS-
600 (Pentair-SHURFlo,
Costa Mesa, CA)
SC-ET HD electrostatic
sprayer (Electrostatic
Spraying Systems ESS,
Watkinsville, GA)
Figure 1. Electric Backpack Sprayer (A);
SC-ET HD Air-Assisted Electrostatic
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COUPON TEST RESULTS
0)
n
n
1 'e
£
cc
U) 4.0
o
_l
0 3.0
1 J
t2.0j
W
1.0
0.0
Surface Log Reduction:
Backpack Sprayer vs. Electrostatic Sprayer
7.7
7.0
5.7
7.3
7.2
6.9
7.2
Nitrile
Butyl Latex Tyvek Tychem Neoprene Chemtape
¦ Backpack Sprayer (7.2 ± 0.4) Electrostatic Sprayer (7.0 ± 0.7)
*Denotes no CFU detected above detection limit
Figure 3. Surface Decontamination Efficacy by Material Type
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MANIKIN TEST RESULTS
In this follow-on study, a comparison of the two
sprayer types (ESS and CBS) for personnel
decontamination was performed on manikins with
PPE ensembles to provide more realistic conditions
as compared to flat coupon surfaces. Manikins
(Figure 4A) in Level C ensembles (Figure 4B) were
inoculated with Bg in seven delineated sampling
locations using either liquid or aerosol inoculation
techniques. The average concentration at each
location was 1 X 107 Bg spores, based on triplicate
positive control manikins, which allowed for a 6 LR
to be quantified.
(a)
-------
Liquid Inoculation Aerosol Inoculation
Positive Control Manikins -Jr
ESS - 2 min Spray Duration
I
~ ill
Anterior
• i
S X
¦
ESS - 4 min Spray Duration
¦ ¦
Anterior
IB
Posterior
¦¦
| •
Anterior
CBS - 2 min Spray Duration
I
mm
a
~¦i
Posterior
¦B® •!
H
Bi
Anterior
¦¦
Posterior
• Denotes Inoculation
Location E0 E1 E2 E3 E4 E5 E6 E7 E8
Figure 6. Sample Recoveries for Liquid Inoculations (A-D) and Aerosol Inoculations (E-H). Heat map legend
shows concentration in exponential form where El = 10, EE = 10s, etc.
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Decontamination efficacy for both sprayers using DB was greater following aerosol inoculation as
compared to liquid inoculation, potentially due to the pooling or clumping of spores that can be
characteristic of liquid inoculation. The pooling/clumping can shield the lower layers of spores from
direct contact with the decontaminant and inhibit efficacy.
When further comparing the ESS with the CBS, both sprayers were successful in decontaminating a
complete PPE assembly donned on manikins. However, some low-level spore contamination remained
in hard-to-reach areas (glove, boot) following decontamination with the CBS (liquid inoculation, Figure
6D) and the ESS for the 2-min spray duration (liquid and aerosol inoculation, Figures 6B and 6F).
Therefore, it was decided to add an additional time point of a 4-min spray duration for the ESS. With the
additional 2 minutes of spray duration, the ESS overall average decontamination efficacy for both liquid
and aerosol inoculation was greater than a 6 LR (Figures 6C and 6G). The CBS also demonstrated a greater
than 6 LR for both liquid and aerosol inoculation (Figures 6D and 6H).
Table 2 provides a summary of test results by sprayer type including decontamination efficacy and
reaerosolization. Reaerosolization was observed to be 2-3 orders of magnitude higher for the CBS during
the spray decon process, likely due to the higher sprayer pressure and volume of decontaminant sprayed
onto the manikin from the CBS. Higher levels of aerosolized spores were observed with aerosol
inoculation relative to liquid inoculation, regardless of sprayer type used.
Table 2. Summary of Manikin Findings by Sprayer Type
Sprayer
Inoculation
Spray
Contact
Decon Efficacy
Reaerosolization
Type
Duration
Time
(Avg LR)
(Avg Log CFU)
ESS
Aerosol
2 min
5 min
4.9
1.4
Liquid
2 min
5 min
5.6
0.26
Aerosol
4 min
5 min
7.5
1.2
Liquid
4 min
5 min
6.1
0.28
CBS
Aerosol
2 min
5 min
6.8
4.0
Liquid
2 min
5 min
6.2
1.7
CONCLUSIONS
In both studies (coupon and manikin), ESS and CBS were shown to be effective and achieved a > 6 LR on
PPE using DB as a decontaminant, though the ESS needed double the spray duration. The ESS used less
decontaminant, produced less aqueous waste and reaerosolized less spores from the PPE during
decontamination. However, thorough coverage of the PPE with the ESS, due to lower liquid volume, is
essential for efficacy. The advantages and disadvantages of each sprayer type should be weighed when
using in a decon line scenario.
The ESS still needs to be tested for efficacy and functionality in a field setup to fully determine its
logistical feasibility in a personnel decon line. Additional efforts will evaluate scale-up to an automated
field deployable decon unit and investigate efficacy of additional decontaminants and ESS sprayers.
DISCLAIMER
The U.S. Environmental Protection Agency, through its Office of Research and Development, funded and
managed the research described herein through Contract No. EP C-15-008 with Jacobs Technology, Inc.
Compilation of this technical information was conducted by Eastern Research Group, Inc., under contract
Ml U.S. Environmental Protection Agency EPA/600/S-20/366
Hi! Office of Research and Development October 2020
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68HERC19A0004. This summary has been subjected to the Agency's review and has been approved for
publication. Note that approval does not signify that the contents reflect the views of the Agency.
Mention of trade names, products, or services does not convey official EPA approval, endorsement, or
recommendation.
REFERENCES
1. USEPA. 2018. Evaluation of Electrostatic Sprayers for Use in a Personnel Decontamination Line
Protocol for Biological Contamination Incident Response Operations. US Environmental Protection
Agency, Washington, DC, EPA/600/R-18/283.
2. Archer, J, A Touati, RL Mickelsen, L Oudejans, MW Calfee, SD Lee, A Abdel-Hady, and K May. 2020.
Evaluation of Conventional and Electrostatic Sprayers for Decontamination of PPE-covered
Manikins in a Personnel Bio Decontamination Line. (Draft manuscript for publication).
3. USEPA (US Environmental Protection Agency). 2015a. Decontamination Line Protocol Evaluation for
Biological Contamination Incidents. Assessment and Evaluation Report. National Homeland Security
Research Center, Office of Research and Development, Washington, DC. EPA/600/R-14/476.
4. Kabashima, J, DK Giles, and MP Parrella. 1995. Electrostatic Sprayers Improve Pesticide Efficacy in
Greenhouses. California Agriculture. 49(4): 31-35.
5. Electrostatic Spraying Systems (ESS). SC-ET Technical Specifications.
http://maxcharge.com/products/sc-et/. Last accessed September 2, 2020.
6. USEPA. 2015b. BioResponse Decontamination Line SOP. Revision 2.0. Chemical, Biological,
Radiological, and Nuclear Consequence Management Advisory Division (CBRN
CM AD), https://response.epa ¦gov/sites/12600/files/BioResponse%20Decontamination%20Line%20
SOP.pdf. Last accessed September 23, 2020.
7. Lee, SD, SP Ryan, and EG Snyder. 2011. Development of an Aerosol Surface Inoculation Method for
Bacillus Spores. Applied and Environmental Microbiology. 77(5): 1638-1645.
CONTACT INFORMATION
For more information, visit the EPA Web site at http://www2.epa.gov/homeland-security-research.
Technical Contact: John Archer (Archer.John@epa.gov)
General Feedback/Questions: Kathy Nickel (nickel.kathy@epa.gov)
U.S. EPA's Homeland Security Research Program (HSRP) develops products based on
scientific research and technology evaluations. Our products and expertise are widely used in
preventing, preparing for, and recovering from public health and environmental emergencies
that arise from terrorist attacks or natural disasters. Our research and products address
biological, radiological, or chemical contaminants that could affect indoor areas, outdoor
areas, or water infrastructure. HSRP provides these products, technical assistance, and
expertise to support EPA's roles and responsibilities under the National Response
Framework, statutory requirements, and Homeland Security Presidential Directives.
U.S. Environmental Protection Agency
Office of Research and Development
EPA/600/S-20/366
October 2020
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