technical BRIEF
BUILDING A SCIENTIFIC FOUNDATION FOR SOUND ENVIRONMENTAL DECISIONS
www. epa .gov/researc h
Sampling Procedures Using Commercially Available Robotic
Floor Cleaners for Bacillus anthracis Spores
INTRODUCTION
Following the 2001 intentional contamination incidents
involving Bacillus anthracis in the United States (DOJ
2010), the research need for sampling methods for the
remediation of contaminated buildings became evident.
Subsequently, surface sampling studies were
emphasized due to the direct impact that sampling
results have on decontamination decision making. Even
though there have been improvements in methods and
procedures for real-world applications, significant
improvement in sampling and analysis processes in the
event of a biological attack on a wide urban area is still
needed. The currently recommended surface sampling
approaches require the use of varied methods that can be Figure 1.
both labor intensive and expensive to implement.	Example of robotic floor cleaners
Research indicates that commercially available robotic	(RFCs).
floor cleaners (RFCs, Figure 1) offer a safe, efficient, and economical option in addition to
currently-used surface sampling methods.
Results (Figure 2) from previous laboratory studies demonstrate sampling (collection) using
RFCs can be as efficacious on porous and nonporous surfaces as presently recommended
methods such as the use of swabs, wipes, and vacuums fitted with filter-type collection media
100
Laminate
Carpet T
£ 100
R1 R2
R3
Figure 2.
Recovery of bacterial spores by robotic floor cleaners compared to
currently recommended surface sampling methods. Five different
RFCs were tested for laminate and three for carpet. R1, R2, R3: dry
vacuum based RFC; R4: mopping RFC; R5: wet vacuum RFC
typically used on small
discrete areas. RFCs use
mechanisms for surface
sampling similar to the
methods applied in
traditional processes such
as vacuuming, sweeping,
and scrubbing. Many
RFCs have functions and
sensors allowing for
enhanced cleaning
performance and
operation in multiple
rooms on one battery
charge. Such a procedure
used in B. anthracis spore
sampling would permit
fewer samples compared
EPA/600/S-17/261

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Operational Assessment of Robotic Floor
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June 30, 2017
to currently used sampling methods, thereby lessening the burden placed on laboratories. Due
to their autonomy, the robots expand the ability to sample limited-access and highly
contaminated areas. There is also a potential for a reduction in personnel needs, for less time in
the contaminated areas, and, most importantly, for lowered exposure risks for responders.
The sampling procedures that have been developed detail the step-by-step process for
sampling a horizontal surface (e.g., floor) using an RFC. An equipment description and supply
list describe the materials needed for sampling and how to secure the RFC unit for shipment,
storage, and analysis. In the event of a biological contamination incident, specific pre-
deployment preparations must be made to prepare the RFC for sample collection. After sample
collection, handling guidelines and documentation instructions preserve the sample and address
quality assurance requirements.
The RFC sampling procedure was used to sample a mock-up of a concrete subway station
during a recent field study (EPA 2017). The results clearly showed that the RFC sampling
method provides the benefits of reduced sampling time during a response, fewer samples
requiring processing, detection of spore presence at unknown hot spots of contamination,
improved detection of widespread contamination when concentrations are close to (or
potentially below) detection limits for traditional surface sampling methods, and shortened
timeline to response and recovery. In addition, the field study results confirmed the following
cautions for using these methods:
•	The tested composite sampling methods generated a large quantity of debris/dust in
the sampling media. It is necessary to develop efficient sample processing procedures
prior to analysis either at the site or at the laboratory.
•	It was difficult to assess the actual sampled area due to the unpredictable movement of
the robots. RFCs may stop sampling due to high filter pressure drop on dusty surfaces.
It is recommended that a magnetic strip be used to pre-define a discrete sampling area
(-100-200 ft2, dependent upon the amount of floor debris present).
SCOPE AND APPLICABILITY
The sampling procedures have been developed by the U.S. Environmental Protection Agency's
(EPA's) Homeland Security Research Program within EPA's Office of Research and
Development jointly with the Chemical, Biological, Radiological and Nuclear Consequence
Management Advisory Division within EPA's Office of Land and Emergency Management. The
procedures are intended to guide trained incident-responders step-by-step to collect
environmental samples following a biological contamination incident. The procedures are
applicable to the collection of surface-bound particulates and microorganisms using off-the-
shelf RFCs following a contamination incident. The purpose of the procedures is to guide the
process of preparation, deployment, and collection using RFCs for sampling surfaces from a
specified area. The collected samples will be used to determine presence/absence and/or
contamination level after natural outbreaks and intentional or accidental releases of pathogenic
microorganisms and biotoxins
At the date of this publication, the RFC sampling procedures have been partially characterized
for deployment feasibility and collection performance for bacterial spores. At the time of
publication, these procedures have not been validated. The Draft procedures will be updated or

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Operational Assessment of Robotic Floor
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June 30, 2017
replaced with a fully characterized and validated sampling procedures upon availability. During
emergency situations, the use of non-validated methods can be warranted where validated
methods are not available. EPA's use of non-validated methods must adhere to the EPA's
Forum on Environmental Measurement (FEM) policy directive on method validation (EPA 2010).
Further information on method validation can be found in Validation of U.S. Environmental
Protection Agency Environmental Sampling Techniques that Support the Detection and
Recovery of Microorganisms (EPA 2012).
ADDITIONAL STUDIES
In 2013, U.S. EPA staff published two studies examining RFCs for surface sampling. In the first
study published (Lee et al. 2013), testing was conducted using five commercially available
robots on various indoor flooring surface materials. The purpose of this experiment was to
determine how robotic floor cleaners (RFCs) used for sampling of B. atrophaeus spores (a
surrogate for B. anthracis) compare to the currently recommended surface sampling methods.
Some of the robotic cleaners performed as well as the respective floor sampling methods
currently in use. The second published study (U.S. EPA 2013) evaluates the efficacy of
commercially available, off-the-shelf RFCs as an alternative sampling technique for surfaces
contaminated with Bacillus spores. The robots were tested on porous and nonporous surfaces
and were evaluated in terms of efficiency, availability, and cost. The highest performing RFCs
from this set were further tested at different levels of contamination. By comparing recoveries (of
colony forming units), sampling via some RFCs was found to be as efficacious as other
sampling methodologies currently recommended.
In Lee et al. (2014), commercially available vacuum-based and wetted-wipe-based robot
cleaners were tested at different spore loading levels. The sampling ability of the RFC was
evaluated in both hot spot and widely dispersed contamination scenarios. Cleaning robots were
found to be capable of sampling as effectively as the currently used methods at different spore
loading levels. The robots can improve the detection capability and cover a larger area than
currently recommended sampling methods.
The EPA's recent report (U.S. EPA 2017) evaluates the field use of commercially available, off-
the-shelf RFCs for surfaces contaminated with Bacillus spores as well as other composite
sampling methods. The robots were tested on concrete platform surfaces at a mock subway
station and were evaluated for operational challenges under dusty field conditions.
REFERENCES
DOJ (Department of Justice). 2010. Amerithrax Investigative Summary. Available at
https://www.hsdl.orq/?view&did=28996 (last accessed on March 20, 2018).
EPA (U.S. Environmental Protection Agency.) (2010). Ensuring the validity of agency methods
validation and peer review guidelines: Methods of analysis developed for emergency response
situations. Washington DC: U.S. Environmental Protection Agency. Agency Policy Directive
Number FEM-2010-01.
Lee, S.D., Calfee, M.W., Mickelsen, L., Wolfe, S., Griffin, J., Clayton, M., Griffin-Gatchalian, N.,
and Touati, A. (2013). Evaluation of surface sampling for Bacillus spores using commercially

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June 30, 2017
available cleaning robots. Environmental Science & Technology, 47(6), 2595-2601.
http://dx.doi.orq/10.1021 /es4000356 (last accessed on June 30, 2017).
Lee, S.D., Calfee, M.W., Mickelsen, L., Clayton, M., and Touati, A. (2014). Scenario-based
evaluation of commercially available cleaning robots for collection of Bacillus spores from
environmental surfaces. Remediation, 24(2), 123-133. http://dx.doi.orq/10.1002/rem.21388 (last
accessed on June 30 2017).
U.S. Environmental Protection Agency. (2012). Validation of U.S. Environmental Protection
Agency environmental sampling techniques that support the detection and recovery of
microorganisms. Prepared by: The FEM Method Validation Team, U.S. Environmental
Protection Agency. Washington DC: U.S. Environmental Protection Agency. FEM 2012-01.
U.S. Environmental Protection Agency. (2013). Assessment and Evaluation Report - Evaluation
of Surface Sampling for Bacillus Spores Using Commercially-available Cleaning Robots. June
2013, Research Triangle Park, NC: National Homeland Security Research Center, Office of
Research and Development, U.S. Environmental Protection Agency. EPA/600/R-13/100.
http://nepis.epa.gov/Exe/ZvPDF.egi/P100JDM1.PDF?Dockev=P100JDM1.PDF (last accessed
on June 30, 2017).
U.S. Environmental Protection Agency. (2017). Assessment and Evaluation Report - Field
Application of Emerging Composite Sampling Methods. Washington DC: U.S. Environmental
Protection Agency. EPA 600/R-17/212.
CONTACT INFORMATION
For more information, visit the EPA Web site at https://www.epa.gov/homeland-securitv-
research.
Technical Contact: Sang Don Lee (lee.sangdon@epa.gov)
General Feedback/Questions: Kathv 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.

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