SEPA
www.epa.gov/nhsrc
technical BRI
Evaluation of Fumigant Decontamination Technologies for
Surfaces Contaminated With Bacillus anthracis Spores
EPA investigates the effectiveness of fumigant technologies to decontaminate
surfaces contaminated with biological agents
Background
Because of their potential use as weapons of
mass destruction, biological agents are a
significant terrorist threat. Once released, certain
bacteria and viruses can spread through the air,
water distribution systems, and the food supply
and cause disease or death in humans, animals,
and plants. According to the Centers for Disease
Control and Prevention, Bacillus anthracis, which
causes anthrax, is one of the most important
pathogens on the list of bioterrorism threats.
In the United States, twenty-three people became
infected with anthrax and five died after envelopes
containing B. anthracis spores were mailed to
governmental and news media offices during the
months following the Sept. 11 terrorist attacks.
Sites where letters were received and many U.S.
Postal Service facilities became contaminated with
As part of U. S. EPA's Office of Research and Development,
the National Homeland Security Research Center (NHSRC)
provides products and expertise to improve our nation's ability
to respond to environmental contamination caused by terrorist
attacks on our nation's water infrastructure, buildings and
outdoor areas.
NHSRC conducts research related to:
• Detecting and containing contamination from
chemical, biological, and radiological agents
• Assessing and mitigating exposure to
contamination
• Understanding the health effects of contamination
• Developing risk-based exposure advisories
• Decontaminating and disposing of contaminated
materials.
spores.
Although person-to-person transmission has not been demonstrated, humans can acquire
anthrax by contact with spores on surfaces and in the air. Anthrax is a naturally occurring
disease most commonly found in grazing animals such sheep, cattle, and goats. Spores can be
found in the tissues from infected animals or in contaminated products made from bone, hide,
wool, or hair.
Spores pose a significant threat because they may remain viable for decades, depending on the
environmental conditions. B. anthracis spores can be processed or weaponized and delivered
through the air over wide areas. A major attack using B. anthracis spores could cause many
deaths and interrupt vital civilian and government operations.
One of the key challenges following an attack with biological agents is remediating
contaminated areas for re-entry and re-use. The primary goal is to reduce the cost and time it
takes to effectively remediate an area while protecting workers and nearby residents.
One challenge: to find fumigants effective against B. anthracis spores
6. anthracis forms spores that are highly resistant to severe environmental conditions, including
exposure to harsh chemical and physical treatments. In 2001, when remediation of facilities
EPA/600/S-11/010
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contaminated by B. anthracis spores began, there were no EPA-registered products specifically for
use against the spores. EPA's Office of Pesticide Programs had to issue crisis exemptions for the
sporicidal products needed for remediation.
The Federal Insecticide, Fungicide, and Rodenticide Act Scientific Advisory Panel1 was
convened in 2007 to provide guidance on test methods for determining the efficacy of
antimicrobial products for inactivating B. anthracis spores. The Panel recommended that, in
order to be registered as a sporicidal decontaminant against B. anthracis spores, a
decontaminant technology had to achieve a mean (average) 6 Iog10 reduction in the number of
viable spores in relevant laboratory testing via approved protocols.
EPA's fumigation technology evaluation research
EPA has conducted several tests to collect performance (efficacy) data on several fumigant
technologies that might be used to decontaminate facilities contaminated with B. anthracis
spores [1, 2, 3, 4, 5, 6, 7]. EPA continues to evaluate fumigation technologies for inactivation of
B. anthracis spores and will issue reports and summaries as additional studies are completed.
Fumigants are sometimes referred to as volumetric decontamination technologies, since they
can be applied to decontaminate hard-to-reach places (such as ventilation ductwork) or large
and irregular surfaces or open areas that might be time-consuming and prohibitively expensive
to decontaminate using liquid or foam technologies.
The following fumigant technologies were tested for efficacy against B. anthracis spores:
Decontamination Technology
Cloridox-GMP™
Sabre CI02
CERTEK ® Model 1414RH Formaldehyde
Generator/Neutralizer
Bioquell Clarus C HPV/Bioquell Clarus S HPV
STERIS VHP ®1000ED
Methyl bromide
Ozone Generator AC-2045
ProFume ®
Active Component
Chlorine dioxide
Chlorine dioxide
Formaldehyde
Hydrogen peroxide
Hydrogen peroxide
Methyl bromide
Ozone
Sulfuryl fluoride
Vendor or Source
ClorDiSys Solutions, Inc.
Sabre Technical Services LLC
CERTEK, Inc.
Bioquell, Inc.
STERIS Corp.
Unknown
IN USA, Inc.
Dow Agro Sciences LLC
Abbreviations
Cloridox
Sabre
CERTEK
BioQ C/BioQ S
STERIS
MeBr
Ozone
SuFI
Final Meeting Minutes for July 17-18, 2007 Scientific Advisory Panel: Guidance on Test Methods for
Demonstrating the Efficacy of Antimicrobial Products for Inactivating Bacillus anthracis Spores on Environmental
Surfaces
Generally, the major factors influencing fumigant choice are the effectiveness of the fumigant
against the biological contaminant on the materials being decontaminated; the ability to
achieve the necessary fumigation requirements (for example, fumigant concentration,
temperature, relative humidity) in the field-use condition, compatibility with materials (to
minimize damage and reduce cost); ventilation requirements for fumigant application;
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containment of the fumigant; the type of aeration and fumigant capture approaches required
to clear the fumigant once decontamination has been achieved; availability of personnel or
companies with expertise and the needed equipment to meet required fumigation parameters;
health, safety, and environmental considerations or regulatory requirements; and cost. Once a
fumigant is chosen, the key process variables that must be effectively controlled for successful
fumigation are fumigant concentration, contact time with materials, and, for some, relative
humidity (RH) and temperature.
Summary of Major Conclusions From Cited EPA Research on Fumigant Technologies
(see Technology Evaluation Materials Referenced for the studies that serve as the basis for this
technical brief)
Fumigant
Chlorine dioxide
Hydrogen peroxide
Formaldehyde
Methyl bromide
Ozone
Sulfuryl fluoride
Major Conclusions From Cited Studies
Material type: Fumigation efficacy was a strong function of material type [1 ,2,7]; effectiveness has been
demonstrated on all porous and non-porous material tested.
Relative humidity: Fumigation efficacy was greater at 75% RH than at 40% [5]; and at 80-84 % than at 71 -
75% [7]
Inoculant quantity: Decrease in fumigant efficacy on all coupon material types was seen with 1 x 108
colony forming units (CFU) per coupon compared with 1 x 1 07 or 1 x 1 06 CFU per coupon [2]
Organism: Efficacy varied with strain of B. anthracis [Ames or NNR1 A1 ] [7]
Organic burden: Added organic burden had "negligible" effect on fumigation efficacy [2, 7]
Other: For some materials, the time required to achieve successful fumigation was determined to be
independent of fumigant concentrations used; mean logic reductions were independent of CI02 generation
methods (wet versus dry) [1]
Material type: Mean logic reductions were observed to be a strong function of material type [2]; efficacious
fumigation to achieve a 6 logic reduction is a function of material type and contact time [7]; greater mean
logic reductions were seen on non-porous surfaces [4]
Inoculant quantity: Significant decrease in the effectiveness observed when the spore inoculation was
increased to 1 x 1 08 CFU per coupon from 1 07 or 1 x 1 06 [2]
Material type: Mean logic reductions varied according to coupon material type; under study conditions,
material porosity did not appear to affect fumigant efficacy [3]
Organism: Efficacy against B. anthracis was higher than against B. subtilis [3]
Material type: Mean logic reductions varied according to coupon material type, fumigant concentration, and
contact time [7]; effectiveness has been demonstrated on all porous and non-porous material tested.
Relative humidity or temperature: fumigant efficacy was marginally (not practically significantly) greater at
75% RH than at 40% [7]; efficacy was higher at 36° C than at 25 ° C [7]
Organism: Under different conditions, which achieved from 1 to 6 mean logic reductions in B. anthracis on
glass, little or no efficacy was observed against B. subtilis (this non-pathogenic spore is significantly more
difficult to inactivate than B. anthracis)
Relative humidity: Mean logic reductions were higher at 85% RH than at 75% [6]
Other: Mean logic reductions were less than 1 .5 [6]
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Summary of Major Fumigant Technology Results Against Bacillus anthracis Spores on Coupons of Various Common
Indoor Materials
Coupon Materials
Aluminum
Carpet (industrial grade)
Ceiling Tile
Cinder Block (painted)
Cinder Block (unpainted)
Computer Keyboard Keys
Glass
Insulation (cellulose)
Joint Tape Paper or Wallboard
Paper (painted)
Laminate (decorative)
Metal Ductwork (galvanized)
Particle Board
Pine Wood (bare)
Steel (painted I-beam)
Fumigant Technologies Tested
Chlorine Dioxide
Sabre
[5]
V
V
nt
nt
nt
V
nt
nt
V
nt
nt
nt
nt
nt
Sabre
[1]
nt
V
^
nt
^
nt
nt
nt
^
nt
nt
nt
V
V
Sabre
[7]
nt
V
nt
V
nt
nt
V
V
nt
V
V
V
nt
nt
Cloridox
[1]
nt
V
V
nt
V
nt
nt
nt
^
nt
nt
nt
V
V
Hydrogen Peroxide
BioQC
[4]
nt
^Q^
nt
V
nt
nt
^
nt
^
V
V
nt
^
nt
BioQC
[5]
nt
V
^o^
^-
nt
nt
V
nt
nt
V
V
nt
^r-
nt
BioQS
[5]
^
^Qf^
nt
nt
nt
V
nt
nt
V
nt
nt
nt
nt
nt
STERIS
[5]
V
V
^or"
V
nt
V
V
nt
V
V
V
nt
^Qf^
nt
STERIS
[7]
^
V
V
^
nt
V
^
^Q^
^
^
V
^0^
^
nt
Formal-
dehyde
CERTEK
[3]
nt
V
nt
V
nt
nt
V
nt
V
V
V
nt
V
nt
Methyl
Bromide
MeBR
[7]
nt
V
V
V
nt
nt
V
V
nt
V
V
nt
V
nt
Ozone
Ozone
[6]
nt
nt
nt
nt
nt
nt
V
nt
nt
nt
nt
nt
V
nt
Sulfuryl
Fluoride
SuFI
[6]
nt
nt
nt
nt
nt
nt
^Q^
nt
nt
nt
nt
nt
^Qr"
nt
A mean 6 log™ or greater reduction of B. anthracis spores was observed on this material in at least one test condition in this study
A less than 6 log™ reduction of 3. anthracis spores was observed on this material for all test conditions in this study
Material was not tested in this study
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Technology Evaluation Materials Referenced
[1] Rastogi, V., Ryan, S., Wallace, L, Smith, S., Shah, S., and Martin G. 2010.
Systematic Evaluation of the Efficacy of Chlorine Dioxide Decontamination of Building Interior
Surfaces Contaminated with Anthrax Spores. Applied and Environmental Microbiology.
76(10):3343-3351.
[2] Rastogi, V., Wallace, L., Smith, L, Ryan, S., and Martin, B. 2009. Quantitative Method To
Determine Sporicidal Decontamination of Building Surfaces by Gaseous Fumigants, and Issues
Related to Laboratory-Scale Studies. Applied and Environmental Microbiology. 75(11):3688-
3694.
[3] Rogers, J., Choi, Y., Richter, W., Rudnicki, D., Joseph, D., Sabourin, C., Taylor, M., and
Chang, J. 2007. Formaldehyde gas inactivation of Bacillus anthracis, Bacillus subtilis, and
Geobacillus stearothermophilus spores on indoor surface materials. Journal of Applied
Microbiology. 103(4):1104-1112.
[4] Rogers, J., Sabourin, C., Choi, Y., Richter, W., Rudnicki, D., Riggs, K., Taylor, M., and
Chang, J. 2005. Decontamination assessment of Bacillus anthracis, Bacillus subtilis, and
Geobacillus stearothermophilus spores on indoor surfaces using a hydrogen peroxide gas
generator. Journal of Applied Microbiology. 99(4):739-748.
[5] Ryan, S. 2010. Persistence Testing and Evaluation of Fumigation Technologies for
Decontamination of Building Materials Contaminated With Biological Agents. Washington, D.C.:
U.S. Environmental Protection Agency. EPA/600/R-10/086.
[6] U.S. EPA. 2010. Evaluation of Sulfuryl Fluoride and Ozone Fumigation Technologies to
Inactivate Bacillus anthracis Spores. Technology Evaluation Report. Washington, D.C.: U.S.
Environmental Protection Agency. EPA/600/X-10/032.
[7] U.S. EPA, 2011. Systematic Investigation ofLiguid and Fumigant Decontamination Efficacy
Against Biological Agents Deposited on Test Coupons of Common Indoor Materials.
Investigation and Technology Evaluation Report. Washington, D.C.: U.S. Environmental
Protection Agency. EPA/600/R-11/076.
See Also for Related Information
Canter, D., Gunning, D., Rodgers, P., O'Connor, L., Traunero, C., and Kempter, C. 2005.
Remediation of Bacillus anthracis Contamination in U.S. Department of Justice Mail Facility.
Washington, D.C.:U.S. Environmental Protection Agency. EPA/600/R-10/154. 2005.
Estill, C., Baron, P. , Beard, J., Hein, M., Larsen, L., Rose, L., Schaefer, F., Noble-Wang, J.,
Hodges, L., Lindquist, H., Deye, G., and Arduino, M. 2009. Recovery efficiency and limit of
detection of aerosolized B. anthracis Sterne from environmental surface samples. Applied and
Environmental Microbiology. 75(13):4297-4306.
U.S. EPA. 2010. Biological Sample Preparation Collaboration Project: Detection of Bacillus
anthracis Spores in Soil. Washington, D.C.:U.S. Environmental Protection Agency. EPA/600/R-
10/177.
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U.S. EPA. 2010. Determining the Efficacy of Liquids and Fumigants in Systematic
Decontamination Studies for Bacillus anthracis Using Multiple Test Methods. Washington,
D.C.:U.S. Environmental Protection Agency. EPA/600/R-10/088.
Contact Information
For more information, visit the EPA Web site at www.epa.gov/nhsrc.
Technical Contacts: Joseph Wood (wood.joe@epa.gov)
Shawn Ryan (ryan.shawn@epa.gov)
General Feedback/Questions: Kathy Nickel (nickel.kathy@epa.gov)
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