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technical BRIEF
BUILDING A SCIENTIFIC FOUNDATION FOR SOUND ENVIRONMENTAL DECISIONS
Summary of the Effectiveness of Volumetric
Decontamination Methods as a Function of
Operational Conditions
INTRODUCTION
One of the most efficient and thorough decontamination methods available for biological agents
is fumigation. Fumigation has been used for over 100 years and is routinely applied to treat
against termites and other pests, molds, and fungi. It is most useful in difficult-to-access spaces,
such as heating, ventilation, and air conditioning (HVAC) systems, and where aerosolizable
particulates are present, as might be the case with contamination from a Bacillus anthracis
spore mixture manufactured as a powder. Fumigants include a wide variety of generally
gaseous compounds with one general commonality: they are extremely toxic to living
organisms, including humans. Therefore, fumigation must be conducted by highly trained and
experienced workers.
The volumetric decontamination methods discussed consist of fumigation techniques that are
used to decontaminate large areas contaminated by B. anthracis spores and any size area
contaminated by aerosolized B. anthracis spores. These methods include fumigation techniques
using methyl bromide, chlorine dioxide, formaldehyde, hydrogen peroxide, ethylene oxide,
methyl iodide, ozone, and fogging with sporicidal liquids.
EPA has comprehensively evaluated numerous volumetric decontamination techniques for their
efficacy against the spores of B. anthracis and its surrogates under a variety of operational
parameters. However, in a wide-area incident, limited availability of supplies and trained
personnel, logistical obstacles, or other unique challenges may force the use of alternative
approaches to accomplish the mission at hand in an acceptable timeframe. Many of these
alternative approaches might be unproven in the field and will have to be selected based on the
best professional judgment of subject matter experts, such as building engineers and
decontamination experts, or decision-makers.
VOLUMETRIC DECONTAMINATION METHODS AND OPERATIONAL
PARAMETERS
Although numerous fumigants have been comprehensively evaluated, only one is currently
registered as a sporicidal decontaminant1 for inactivation of B. anthracis spores: DIKLOR G
Chlorine Dioxide Sterilant Precursor (Sabre Oxidation Technologies, Inc.; EPA Registration No.
1 To be considered effective and registered as a sporicidal decontaminant against B. anthracis spores, a
decontaminant technology has to achieve a mean (average) 6 logio reduction in the number of viable
spores in relevant laboratory testing via approved protocols.
September 2015
EPA/600/S-15/190
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73139-3; active ingredients: sodium chlorite {25%}; product label posted at:
http://www.epa.gov/pesticides/chem search/ppls/073139-00003-20140128.pdf). EPA issued a
quarantine exemption for the use of several fumigation products against B. anthracis including:
ethylene oxide, paraformaldehyde, and hydrogen peroxide vapor. The products listed in the
quarantine exemption are supported by available safety and efficacy data, including data from
EPA cited in this technical brief. In addition, Vaprox® Hydrogen Peroxide Sterilant (STERIS
Corporation) is a registered sporicide that has been shown to be effective in previous 6.
anthracis decontamination events (EPA Registration No. 58779-4; active ingredients: hydrogen
peroxide {35%}; product label posted at:
http://www3.epa.qov/pesticides/chem search/ppls/058779-00004-20120221.pdf).
Fumigation requires a great deal of preparation and monitoring to ensure that it is performed in
a safe and efficacious manner. Precise control of operational parameters such as the
concentration of the fumigant, relative humidity (RH), temperature, and duration of fumigation is
required. EPA has identified many of the operational parameters necessary for specific
volumetric decontamination techniques. Table 1 lists some, but not all, of the fumigant
conditions that have been shown to be effective, or are the conditions that have been registered
or used in previous B. anthracis decontamination events. Refer to the descriptions below the
table for a more information or to the actual references.
Table 1. Fumigants and Operational Parameters
Fumigant Name
[Reference Nos.]
Methyl Bromide
[1-4]
Chlorine Dioxide
[5-18]
Formaldehyde
[19]
Hydrogen Peroxide
(vapor)
[20-26]
Description
Colorless,
odorless, toxic,
non-flammable
gas
Yellowish-green
gas; strong
oxidizing agent;
bleach/chlorine
odor
Colorless gas;
pungent odor;
flammable
Colorless liquid;
little to no odor;
strong oxidizer
Fumigation Operational Parameters
Concen-
tration
212-300
mg/L
200-3000
ppm
1,100ppm
5-400
ppm
Relative
Humidity
%
75
70-75
50-90
Minimal
Tem-
perature
°C (°F)
22-32
(72-90)
21-27
(70-80)
16-32
(60-90)
>18(>65)
Duration
(hours)
18-36
3-12+
10
05to1
week
depending on
concentration
Comments
Recognized as a stratospheric
ozone-depleting substance;*
reacts with liquid aluminum
Used during Capitol Hill 6.
anthracis response.
Extensively tested by EPA.
Commercially available as
liquid (formalin) and solid
(paraformaldehyde)
Steris Product registration
label specifies 30 minutes at
400 ppm, or 90 minutes at 250
ppm. However, tests (EPA
and others) show these
conditions are not always
effective for some materials.
* "Exemption for Use" request/approval may be needed under Section 604 (d) of the Clean Air Act.
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Table 1. Fumigants and Operational Parameters continued
Fumigant Name
Peracetic Acid
(PAA) (fogging)
[29-30]
Ethylene Oxide
[27]
Methyl Iodide
[28]
Ozone
[31]
Description
Clear liquid; pungent
vinegar-like odor;
corrosive; oxidizer
Flammable gas;
reactive; potentially
explosive; pleasant
aroma
Colorless non-
flammable liquid;
pungent odor
Colorless or blue gas
with pungent odor
Fumigation Operational Parameters
Concen-
tration
>10mL
of4.5%
PAA per
1m3
volume
150-
>600
mg/L
200 mg/L
12,000
ppm
Relative
Humidty
%
75-80
50-75
>70
85%
Tem-
perature
°C (°F)
70-80
37-50
99-122)
25 (77)
21-27
(70-80)
Duration
(hours)
3 or more
1.5to>3
>12
9-12
Comments
PAA is produced and maintained
in equilibrium with acetic acid,
hydrogen peroxide, and water
Explosive nature precludes use
for large volumes; suggested for
fumigation of sensitive items
inside chambers or smaller areas
Although all pesticide
registrations of methyl iodide
products have been cancelled,
the reagent is still widely
available.
In general, fumigants are more effective with relatively higher gas concentrations, higher
temperatures and relative humidity percentages, and longer durations/exposure times.
However, these operational parameters are usually dependent to each other. Therefore, in
some cases, the duration of the fumigation could be reduced if a higher gas concentration and
higher temperature or percent relative humidity is used. Lower gas concentrations with a longer
durations might also be effective. Additionally, concentration amounts might vary based on
structure size and contents and the ability to maintain optimal relative and temperature.
The space to be fumigated must be relatively gas-tight or in some way able to control the
exfiltration of the fumigant. Preventing leakage of the fumigant can be accomplished by several
different control methods. One method would be to exert a slight negative pressure on the
space, withdrawing fumigant and air from the space, and then filtering and scrubbing the
withdrawn air as necessary before discharging it into the atmosphere. This method has provided
improved air circulation in particular in lengthy and convoluted volumes, such as heating and
ventilation ductwork, while also assuring that the correct fumigant concentration reaches all
areas of the passage.
Operational parameters, temperature and RH, need be achieved and maintained at the optimal
levels required for efficacious decontamination before and during the fumigation. Achieving and
maintaining the necessary humidity levels in a space or building can be particularly difficult
given the relatively high minimum values, often about 70%, required for most fumigants. The
problem would be exacerbated in a northern city during winter. An industrial-level humidifier will
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likely be required when fumigating large spaces. Additionally, the initial sorptive capacity of the
space due to furnishing and materials could be extremely high. The contents (e.g., paper, foam,
fabrics, concrete, galvanized metal, water) within a volume to be fumigated should be factored
into the fumigation decision process, as specific contents may act as sinks for fumigants, water
vapor (humidity), and heat. To offset the sink effect, large amounts of paper may need to be
removed or pre-humidified before fumigation and large amounts of foam may need to be
removed.
The temperature requirements for fumigation vary according to the fumigant, with requirements
starting at 16°C (60°F). The temperature will need to be assessed to determine if supplemental
heating is required at any point before or during fumigation operations, and if heaters need to be
distributed throughout the structure. Below are general guidelines for heating the structure:
• Multiple heaters may be used throughout the structure.
• Heaters should be controlled from outside the fumigation site to maintain the correct
temperature. Many heaters will have thermostats on the units themselves to control the
temperature.
• Power lines and lines for controlling the heaters need to be placed inside the fumigation
structure.
• The HVAC system fans may be turned on to decontaminate the HVAC duct work as well
as to help circulate air and fumigant within the structure. If additional heating is needed,
the HVAC heating system may be used. If the heater is used, the heater exhaust must
be open and routed back into the structure.
Achieving and maintaining gas concentration can also be challenging as gas concentrations can
decline due to interactions with materials, be diluted by leakage, and decay naturally.
Fumigation specialists will need to ensure that enough fumigant chemicals or their precursors
are brought to the site so that the target concentration can be achieved and maintained in the
volume for the target contact time, overcoming any losses due to adsorption, leakage, and/or
decay. In addition to having enough mass of chemicals on site, the rate of injection of these
chemicals into the building has to be high enough in order to overcome losses and increase
concentration until the target is achieved. As an example, if the target concentration for chlorine
dioxide (CICb) is 3000 ppm, the fumigation specialist must have an injection rate high enough to
overcome losses, otherwise it may take days to reach the 3000 ppm target concentration or it
may not be achievable at all.
Wind can complicate the fumigation of a large structure. Wind can induce pressure differentials,
causing dramatic increases in exfiltration and infiltration of air in buildings. This condition can
create problems from a health and safety standpoint (it could, for example, allow the fumigant to
escape, exposing workers or the public), and increase the difficulty of maintaining optimum
fumigant concentrations and the prescribed humidity and temperatures in the fumigated space.
Therefore, it is advisable to consider the predicted weather prior to scheduling fumigation in
larger structures and buildings.
Once fumigation is complete, aeration of the structure will be necessary to reduce fumigant
concentrations to levels acceptable for reentry. Depending on the fumigant and the operational
parameters used, aeration can be accomplished via natural aeration, operation of a scrubber
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(e.g., activated carbon system), or operation of negative air machines (NAMs) with high-
efficiency participate air (HEPA) filters. It is important to note that fumigant adsorption may be
followed by latent desorption (off-gassing) for extended periods of time following the initial
fumigation and this should be considered when planning and implementing the aeration
process.
VOLUMETRIC DECONTAMINATION METHODS SITE PREPARATION AND
FUMIGANT OPTIONS
General site preparation steps, a brief description of the various fumigant options, and an
overview of sensitive material decontamination techniques are provided in this section.
Site Preparation Steps Common to All Methods
Many of the procedures for fumigation and fogging, including such actions as sealing of a room,
tenting of a building, and set up of humidifiers, are identical or similar for each fumigant. The
general preparation steps are summarized below, although not all of these steps may be
required.
• Sealing, tenting, and elimination of air leakage.
• Installation of HEPA air scrubber.
• Installation of gas monitoring points.
• Installation of temperature and humidity monitoring instruments.
• Installation of fumigant generating equipment/gases and injection lines.
• Installation of temperature controls.
• Placement of fans.
• Placement of humidifiers.
• Elimination of flame sources (particularly for methyl bromide and formaldehyde).
• Final check and placarding.
• Ambient air monitoring planning and equipment.
Fumigant Options
Methyl Bromide (MB)
Methy bromide (also known as bromomethane) is a colorless, odorless, and nonflammable gas
used as a pesticide to control insects, nematodes, weeds, pathogens, and rodents. In the
United States, MB is used in agriculture as a soil fumigant, commodity treatment, and
quarantine treatment. An "Exemption for Use" request/approval may be needed under Section
604 (d) of the Clean Air Act.2
1 See EPA's website on Critical Use Exemption Information, http://www.epa.gov/ozone/mbr/cueinfo.html
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A laboratory study performed by EPA [1] showed that MB fumigation can effectively inactivate
B. anthracis Ames spores; effective operational parameters are summarized in Table 2.
Table 2. Effective Operational Parameters for B. anthracis Decontamination with Methyl
Bromide
Methyl Bromide Relative Humidity
Concentration (mg/L) (%)
Temperature
Duration
(hours)
75
22 (72)
27 (81)
32 (90)
22 (72)
27 (81)
36
36
24
24
18
The following fumigation procedures are specific for MB.
• Site preparation (see Site Preparation Steps Common to All Methods above).
• Bring the operational parameters, temperature and RH, to the optimal levels required for
efficacious decontamination.
• Fumigation.
o Introduction of MB gas into the area being fumigated while maintaining operational
parameters.
o Monitoring of MB concentration in the fumigation area.
• Aeration.
o Operation of scrubber (activated carbon system) until MB concentrations inside
fumigation area are reduced to acceptable levels followed by natural aeration.
Test data and more specific operational details can be found in the EPA Methyl Bromide Field
Operation Guidance Report [2] and other EPA studies [1, 3-4].
Chlorine Dioxide (CIO2)
CIO2 is a non-flammable yellow-green gas at room temperature and a strong oxidizing agent
with a bleach/chlorine odor. An effective biocide, it has been used for drinking water and
wastewater disinfection and food plant sanitation. It has also been used in large-scale
fumigations and to fumigate areas within the Hart Senate Office Building during the Capitol Hill
B. anthracis incident. EPA test data also suggests that CIO2 may be an effective decontaminant
for soil [5] and surfaces covered with dirt or grime [6].
Previous tests and decontamination events using high levels of CIO2 gas (e.g., 1000 - 3000
ppm) have demonstrated the inactivation of B. anthracis Ames spores, but the use of high CIO2
levels also comes with drawbacks, such as issues with material compatibility and generation
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technology capacity. There are very few companies that have the technology to generate CIO2
at a high enough rate to achieve 3000 ppm in an average sized building. Therefore, selecting
gas concentrations that are lower and adjusting the operational parameters to reach the target
fumigant conditions may be a more practical option for vendors with technologies that produce
CIO2.
EPA tested the efficacy of low level CIO2 gas to guide its use and implementation for
decontaminating indoor office material [7]. The study demonstrated the potential of using
relatively low levels of CIO2 gas (100-300 ppm), accompanied by longer exposure times, for
effective decontamination of surfaces and spaces contaminated by B. anthracis Ames spores.
The study noted that this decontamination approach may be better suited for areas that are not
heavily contaminated and/or that do not contain significant quantities of porous materials such
as carpet and wood. Some examples of effective operational parameters are shown in Table 3.
Table 3. Effective Operational Parameters for B. anthracis Decontamination with Chorine
Dioxide
Chlorine Dioxide
Concentration (ppm)
Relative Humidity
(%)
Temperature
°C (°F)
Duration
(hours)
200-300
3,000
75
>70
>70
25(77)
21-27 (70-80)
21-27 (70-80)
3-12+
3
CIO2 fumigation procedures are listed below:
• Site preparation (see Site Preparation Steps Common to All Methods above).
• Bring the operational parameters, temperature and RH, to the optimal levels required for
efficacious decontamination.
• Fumigation.
o Introduction of CIO2 gas into decontamination area while maintaining operational
parameters.
o Monitoring of CIO2 concentration in decontamination area.
• Aeration.
o Operation of scrubber (activated carbon system or dechlorinating scrubber solution
emitter) until CIO2 concentrations inside fumigation area are reduced to acceptable
levels, followed by natural aeration.
Several additional EPA studies on CIO2 fumigation [5-18] provide test data and details on
operational procedures.
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Formaldehyde
Formaldehyde is a colorless gas at room temperature with a pungent irritating odor. It is
available commercially as a flammable colorless liquid in water solution as formalin or as a
white crystalline solid, paraformaldehyde, produced by the polymerization of formaldehyde.
Formaldehyde gas is generated from using either paraformaldehyde or formalin. Formaldehyde
is used in building materials, to produce many household products, as an industrial fungicide,
germicide, and disinfectant, and as a preservative in mortuaries and medical laboratories.
Formaldehyde occurs naturally in the environment and is produced in small amounts by most
living organisms as part of normal metabolic processes.
A laboratory study performed by EPA [19] showed that formaldehyde fumigation can effectively
inactivate B. anthracis Ames spores on several surfaces including industrial carpet, bare pine
wood, painted concrete, glass, decorative laminate, and galvanized metal ductwork. In the
study, the formaldehyde concentration was maintained at approximately 1100 ppm with a
relative humidity range of 50-90% and a temperature range of 16-32 °C (60-90 °F) during the
10-hr contact time.
Formaldehyde fumigation procedures are listed below:
• Site preparation (see Site Preparation Steps Common to All Methods above).
o Setup of formaldehyde and quenching agent vaporizers.
• Bring the operational parameters, temperature and RH, to the optimal levels required for
efficacious decontamination.
• Fumigation.
o Introduction of formaldehyde gas into decontamination area while maintaining
operational parameters.
o Monitoring of formaldehyde concentration in decontamination area.
o Introduction of quenching agent (typically ammonia) with a hot plate or other
automated equipment to neutralize the formaldehyde.
o Remove the powder formed from the neutralization process.
• Aeration.
o Natural aeration.
Hydrogen Peroxide (H2O2)
Hydrogen peroxide, a colorless liquid with little to no odor, is a strong oxidizer used as a
bleaching agent and disinfectant. While not flammable, it can cause spontaneous combustion of
flammable materials and supports continued combustion because it liberates oxygen as it
decomposes.
Vaprox Hydrogen Peroxide Sterilant is a registered H2O2 product (see previously cited
registration information). The STERIS product registration label specifies fumigation conditions
consisting of 30 minutes at 400 ppm, or 90 minutes at 250 ppm (both at a temperature of 18°C
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(65 °F) or higher) when using the STERIS Vaporized Hydrogen Peroxide (VHP®) generator.
However, tests (EPA and others) show these conditions are not always effective for some
materials. EPA has tested VHP® generators and has identified a H2O2 concentration of 400 ppm
with a minimal exposure duration of 6 hours (i.e., a cumulative exposure of 2400 ppm-hr at a
temperature of 18°C (65 °F) or higher) to be effective for the inactivation of B. anthracis Ames
spores. Several H2O2 vapor generators are commercially available, therefore, modifications to
the operational parameters may be needed to conduct hydrogen peroxide fumigations using
another vendor's generator. Additionally, lower concentrations with longer durations have also
shown to be effective. Refer to the EPA studies on H2O2 fumigations [20-26] for test data and
details on operational procedures.
The following are procedures for the use of H2O2 vapor for the fumigation of buildings and
rooms:
• Site preparation (see Site Preparation Steps Common to All Methods above).
• Bring the operational parameters, temperature and RH, to the optimal levels required for
efficacious decontamination.
• Fumigation.
o Introduction of H2O2 gas into decontamination area while maintaining operational
parameters.
o Monitoring of H2O2 concentration in decontamination area.
• Aeration.
o Operation of NAM(s) with HEPA filter until H2O2 concentrations inside fumigation
area are reduced to acceptable levels.
Ethylene Oxide (EtO)
Ethylene oxide, an organic compound, is a carcinogenic, mutagenic, irritant, and anesthetic gas
with a faintly sweet odor that is flammable at room temperature. EtO is widely used as a
disinfectant and sterilant in hospitals and the medical equipment industry to replace steam in the
sterilization of heat-sensitive tools and items. This gas is a candidate for decontaminating and
sterilizing sensitive items and materials that might be found in museums, such as canvas
paintings and fabrics, in the event of a biological agent release.
Because of the explosive nature of this gas, it should not be used on large volumes. Moreover,
during EtO treatments, ethylene chlorohydrin formation is possible. Therefore aeration, a critical
step post-treatment, may be required more than once, as items have been shown to off-gas EtO
following fumigation. The most likely scenario would be fumigation of items with EtO in a large
chamber or using the Andersen Products mobile system.3 A limited number of smaller, field-
deployable units are also possible for EtO fumigation.
EPA examined the efficacy of EtO against B. anthracis Ames and B. atrophaeus subsp. globigii
spores applied to multiple materials, including the types of sensitive materials found in
'Andersen Products, http://www.anpro.com
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museums or that could be sensitive to other types of decontaminants. Specifically studied were
glass, bare pine wood, painted canvas, archival paper, silk, and carbon steel [27].
Decontamination efficacy was determined based on the log™ reduction in the number of viable
spores recovered from the inoculated samples (with and without exposure to ethylene oxide).
EtO is an effective decontaminant against B. anthracis Ames under optimal combinations of
concentration, contact time, temperature, and relative humidity. At a minimum, the combinations
of parameters shown in Table 4 should be used for EtO to be effective against glass, bare pine
wood, painted canvas, archival paper, silk fabric and carbon steel. In general, as the RH
increases, so does the efficacy. Efficacious treatment is possible even with reduced amounts of
EtO and a shorter contact time as the RH increases.
Table 4. Effective Operational Parameters for B. anthracis Decontamination with Ethylene
Oxide
Etylene Oxide Relative Humidity Temperature
_ ... . ... .... Duration (minutes)
Concentration (mg/L) (%) <>Q ,op»
'
>600 50 50(122) >180
>300 60 50(122) >180
>300 75 37(99) >90
Methyl Iodide (Mel)
Methyl iodide, another fumigant that has been tested for the inactivation of B. anthracis Ames,
can be used as an alternative to MB to expand the decontaminant capacity in the case of a
wide-area B. anthracis incident. Mel has been used as a fungicide, herbicide, and soil
disinfectant and has sporicidal properties similar to those of MB. Although all pesticide
registrations of methyl iodide products in the US have been cancelled, the reagent is still
available. Unlike MB, Mel is not an ozone-depleting substance and is thus not subject to the
Montreal Protocol on Substances that Deplete the Ozone Layer.
EPA studied the decontamination of six types of common indoor and outdoor materials with Mel
[28]. These materials were glass, ceiling tile, carpet, painted wallboard paper, bare pine wood
and unpainted concrete. Decontamination efficacy tests were conducted with spores of virulent
B. anthracis Ames and non-virulent strains (i.e., B. atrophaeus subsp. globigii and B. anthracis
Sterne). Tests were conducted with various temperatures, RH levels, concentrations, and
contact times to assess the effect of these fumigation operational parameters on
decontamination efficacy. Findings showed that a 6-logio reduction can be achieved at a
temperature of 25 °C (77 °F), RH greater than 70%, and a Mel concentration of 200 mg/l held
for a minimum of 12 hours. These results are similar to those achieved with MB. Mel has not
10
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been tested on a field-scale level, but site preparation and operational parameters would be
similar to those for MB.
Peracetic Acid (PAA) (fogging)
Fogging is the process of aerosolizing a liquid into the air as microscopic droplets. It can be
used for the volumetric decontamination of buildings, rooms, and sensitive items. It is important
to select an appropriate fogging device. (Note: some inexpensive devices may not be as
effective because they may produce relatively larger droplet sizes; larger droplets may tend to
settle faster and not reach all surfaces in a contaminated space).
Theoretically, any sporicidal liquid could be fogged to decontaminate B. anthracis spores.
Examples of other candidate liquid sporicidal chemicals include hydrogen peroxide, chlorine
dioxide, formaldehyde, and pH-amended bleach. However, most of the commercially available
foggers used for disinfection (such as for hospitals, clean rooms, veterinary facilities), and
foggers reported in the scientific literature use peracetic acid or hydrogen peroxide.
The fogging procedures discussed here focus on the use of PAA, one of the most effective
active ingredients in liquid sporicidal chemicals. However, the basic principles of fogging
operation are applicable to most other sporicidal liquids.
PAA, a clear liquid with a pungent, vinegar-like odor, is corrosive and an oxidizer. The effective
operational parameters fogging with PAA include a concentration of > 10 mL of 4.5% PAA per 1
m3 volume with a duration of 3 or more hours at 75-80% RH and 21-27 °C (70-80 °F).
The following are procedures for fogging, with emphasis on the use of PAA:
• Site preparation (see Site Preparation Steps Common to All Methods above).
o Installation of fogging equipment and related supplies including the air supply for the
fogger.
• Fogging.
o Introduction of fogged sporicidal liquid into decontamination area while maintaining
operational parameters.
o Monitoring of sporicidal liquid concentration in decontamination area.
• Aeration.
o Natural aeration.
Refer to the EPA studies on fogging with PAA [29-30] for test data and additional details on
operational procedures.
Ozone
In an EPA study [31], ozone fumigation was evaluated for its ability to decontaminate building
materials inoculated with B. anthracis and Bacillus subtilis spores. The study concluded that
ozone gas is a promising fumigant decontamination technology for the inactivation of 6.
anthracis Ames spores on building materials, provided that sufficient concentration, contact
time, temperature and RH are achieved for the various materials being decontaminated. In
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general, decontamination efficacy improved with increasing ozone concentration and RH, and
was affected by the material. The effective operational parameters were identified as a
concentration of 12,000 ppm with an exposure duration of 9-12 hours at 85% RH and 21-27 °C
(70-80 °F).
SENSITIVE MATERIAL DECONTAMINATION TECHNIQUES
The compatibility of sensitive materials and decontamination agents should be understood when
deciding on a cleanup approach. Table 5 lists findings of EPA studies [7, 32] on fumigants and
material compatibility. Tests may be needed for items not evaluated in the past:
Table 5. Findings from EPA Fumigation Tests of Electronic Equipment (Desktop
Computers, Monitors, Fax Machines, Cell Phones, CDs) with Chlorine Dioxide, Hydrogen
Peroxide, Methyl Bromide (with 2% Chloropicrin), and Ethylene Oxide *
Fumigant
Tested
[32]
Findings
Comments
Chlorine Dioxide
At 3000 ppm, fumigation caused some corrosion
around the edges of desktop computers, left
powdery residue and damaged some CD/DVD
drives; with the exception of some DVD drives, the
computers were still in operation with no
replacement parts one year after fumigation; a
separate study [7] showed less detrimental impact
on computer functionality when fumigating with
lower levels of chlorine dioxide.
Computers fumigated with chlorine dioxide were
more prone to physical/functional deterioration
than those fumigated with hydrogen peroxide.
Hydrogen
Peroxide
Fumigation did not appear to affect the electronic
components tested; computer performance did not
appear to be significantly affected up to one year
following fumigation.
Fumigation can be considered a valid option for
whole-building/room decontamination with
sensitive items, but process humidity and
exposure time must be very carefully planned
and controlled to minimize damage to sensitive
items.
Methyl Bromide
(with 2%
Chloropicrin)
Recommended for porous sensitive items (books,
documents, photographs, etc.). It appears to be the
most compatible and least damaging to most
sensitive items. Power supplies in all MB-fumigated
computers failed, some catastrophically, due to the
Chloropicrin; some corrosion of low carbon steel
and steel outlet/switch boxes seen; other materials
with potential for damage include metal bearings
and CD/DVD drives.
For whole building/room fumigations, methyl
bromide is recommended for porous sensitive
items and is recommended over hydrogen
peroxide for most sensitive items. Do not use
methyl bromide with added Chloropicrin for
sensitive items: Chloropicrin has been shown
to cause oxidation or adverse effects on the
electronics.
Ethylene Oxide
Little or no impact for materials tested; generally
the most material-compatible method for
decontamination of high-value irreplaceable
objects; treatment is complicated and must be
performed precisely.
Use in an extremely well-ventilated area; not
suitable for wide-area fumigation in a building or
an environment with an ignition source; it is
recommended that the work either should be
conducted in a dedicated off-site facility or
objects removed to a controlled environment in
another spot within the site.
* It is important to note that the results are for the specific conditions to which the material or equipment was exposed during
testing. Less impact is expected when fumigating at lower concentration or RH.
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CONCLUSION
Many volumetric decontamination technologies exist. These methods include fumigation
techniques using methyl bromide, chlorine dioxide, formaldehyde, hydrogen peroxide, ethylene
oxide, methyl iodide, ozone, and fogging with various agents. Some of the decontamination
technologies presented in this document have proven successful during real-world responses.
In contrast, other technologies have been demonstrated to be effective during laboratory testing
and have not been fully evaluated at the field-scale level. During a response, users of this
document might need to extrapolate experimental findings from the laboratory to the field, then
field-prove and modify the decontamination techniques as necessary to help establish the
process-knowledge required for the environmental- and site-specific conditions.
DISCLAIMER
The U.S. Environmental Protection Agency through its Office of Research and Development
funded and managed the research described herein under several contractual agreements
listed in the references. Compilation of this technical information was conducted by Booz Allen
Hamilton under EP-G13C-00404. 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
Methyl Bromide
1. U.S. EPA. Methyl Bromide Decontamination of Indoor and Outdoor Materials Contaminated
with B. anthracis Spores. U.S. Environmental Protection Agency, Washington, DC, EPA/
600/R-14/170, 2014.
2. U.S. EPA. Methyl Bromide Field Operation Guidance (MB FOG) Report. U.S. Environmental
Protection Agency, Consequence Management Advisory Division (CMAD), April, 2015.
Note: This report is not publicly available. Send requests for the latest version to CMAD.
3. U.S. EPA. Systematic Investigation of Liquid and Fumigant Decontamination Efficacy
against Biological Agents Deposited on Test Coupons of Common Indoor Materials. U.S.
Environmental Protection Agency, Washington, DC, EPA/600/R-11/076, 2011.
4. U.S. EPA. Determining the Efficacy of Liquids and Fumigants in Systematic
Decontamination Studies for Bacillus anthracis Using Multiple Test Methods. U.S.
Environmental Protection Agency, Washington, DC, EPA/600/R-10/088, 2010
Chlorine Dioxide
5. U.S. EPA. Inactivation of B. anthracis Spores in Soil Matrices with Chlorine Dioxide Gas.
U.S. Environmental Protection Agency, Washington, DC, EPA/600/R-12/517, 2012.
6. U.S. EPA. Interactions of CIO2 and H2O2 Fumigants with Dirt and Grime on Subway
Concrete. U.S. Environmental Protection Agency, Washington, DC, EPA/600/R-14/226,
2014.
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7. U.S. EPA. Decontamination of a Mock Office Using Chlorine Dioxide Gas. U.S.
Environmental Protection Agency, Washington, DC, EPA/600/R-14/208, 2014.
8. U.S. EPA. Evaluation of Sporicidal Decontamination Technology: Sabre Technical Services
Chlorine Dioxide Gas Generator. U.S. Environmental Protection Agency, Washington, DC,
EPA/600/R-06/048, 2006.
9. U.S. EPA. Material Demand Studies: Interaction of Chlorine Dioxide Gas with Building
Materials. U.S. Environmental Protection Agency, Washington, DC, EPA/600/R-08/091,
2008.
10. U.S. EPA. Evaluation of Fumigant Decontamination Technologies for Surfaces
Contaminated with Bacillus anthracis Spores. U.S. Environmental Protection Agency,
Washington, DC, EPA/600/S-11/010, 2011.
11. U.S. EPA. Compatibility of Material and Electronic Equipment with Methyl Bromide and
Chlorine Dioxide Fumigation. U.S. Environmental Protection Agency, Washington, DC,
EPA/600/R/12/664, 2012.
12. U.S. EPA. Evaluation of Chlorine Dioxide Gas and Peracetic Acid Fog for the
Decontamination of a Mock Heating, Ventilation, and Air Conditioning Duct System. U.S.
Environmental Protection Agency, Washington, DC, EPA/600/R-14/014, 2014.
13. U.S. EPA. Decontamination Process Indicators: Biological Indicators. U.S. Environmental
Protection Agency, Washington, DC, EPA/600/R-14/239, 2014.
14. U.S. EPA. CDG Research Corp. Bench-Scale Chlorine Dioxide Gas: Solid Generator. U.S.
Environmental Protection Agency, Washington, DC, EPA/600/R-11/199, 2004.
15. Rastogi, V. K., S. P. Ryan, L Wallace, L S. Smith, S. S. Shah, and G. B. Martin. Systematic
Evaluation of the Efficacy of Chlorine Dioxide in Decontamination of Building Interior
Surfaces Contaminated with Anthrax Spores. Applied and Environmental Microbiology.
76(10): 3343-3351,2010.
16. Rastogi, V. K., L. Wallace, L. S. Smith, S. P. Ryan, and G. B. Martin. Quantitative Method To
Determine Sporicidal Decontamination of Building Surfaces By Gaseous Fumigants, and
Issues Related to Laboratory-Scale Studies. Applied and Environmental
Microbiology.!^ 1):3688-3694, 2009.
17. Wood, J., S. P. Ryan, E. Snyder, S. Serre, D. Touati, and M. J. Clayton. Adsorption of
Chlorine Dioxide Gas on Activated Carbons. Journal of Air and Waste Management.
60(8):898-906, 2010.
18. Wood, J. P. and G. B. Martin. Development and Field Testing of a Mobile Chlorine Dioxide
Generation System for the Decontamination of Buildings Contaminated with Bacillus
anthracis. Journal of Hazardous Materials. 164(2-3): 1460-1467, 2009.
Formaldehyde
19. Rogers, J.V., Y.W. Choi, W.R. Richter, D.C. Rudnicki, D.W. Joseph, C.L.K. Sabourin, M.L
Taylor, and J.C.S. Chang. Formaldehyde Gas Inactivation of Bacillus anthracis, Bacillus
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subtilis, and Geobacillus stearothermophilus Spores on Indoor Surface Materials. Journal of
Applied Microbiology. 103(4):1 104-1 112, 2007.
Hydrogen Peroxide
20. U.S. EPA. Compatibility of Material and Electronic Equipment with Hydrogen Peroxide and
Chlorine Dioxide Fumigation. U.S. Environmental Protection Agency, Washington, DC,
EPA/600/R- 10/1 69, 2010.
21. U.S. EPA. Bio-response Operational Testing and Evaluation (BOTE) Project. U.S.
Environmental Protection Agency, Washington, DC, EPA/600/R-13/168, 2013.
22. U.S. EPA. Interactions of CIO2 and hbCb Fumigants with Dirt and Grime on Subway
Concrete. U.S. Environmental Protection Agency, Washington, DC, EPA/600/R-1 4/226,
2014.
23. U.S. EPA. Evaluation of Hydrogen Peroxide Fumigation for HVAC Decontamination. U.S.
Environmental Protection Agency, Washington, DC, EPA/600/R/1 2/586, 2012.
24. U.S. EPA. Determining the Efficacy of Liquids and Fumigants in Systematic
Decontamination Studies for Bacillus anthracis Using Multiple Test Methods. U.S.
Environmental Protection Agency, Washington, DC, EPA/600/R- 10/088, 2010.
25. U.S. EPA. Systematic Investigation of Liquid and Fumigant Decontamination Efficacy
against Biological Agents Deposited on Test Coupons of Common Indoor Materials. U.S.
Environmental Protection Agency, Washington, DC, EPA/600/R- 11/076, 2011.
26. Meyer, K. M., Calfee, M. W., Wood, J.P., Mickelsen, L, Attwood, B. Clayton, M., Touati, A.,
and Delafield, R. Fumigation of a Laboratory-scale HVAC System with Hydrogen Peroxide
for Decontamination following a Biological Contamination Incident. Journal of Applied
Microbiology. 116(3):533-541, 2014.
Ethylene Oxide
27. U.S. EPA. Evaluation of Ethylene Oxide for the Inactivation of B. anthracis-report. U.S.
Environmental Protection Agency, Washington, DC, EPA/600/R- 13/220, 2013.
Methyl Iodide
28. U.S. EPA. Evaluation of Methyl Iodide for the Inactivation of B. anthracis. U.S.
Environmental Protection Agency, Washington, DC, EPA/600/R- 14/229, 2014.
Peracetic Acid (fogging)
29. Wood, J. P., Calfee, M. W., Clayton, M., Griffin-Gatchalian, N., Touati, A., & Egler, K.
Evaluation of Peracetic Acid Fog for the Inactivation of Bacillus anthracis Spore Surrogates
in a Large Decontamination Chamber. Journal of Hazardous Materials. 250-251:61-67,
2013.
30. U.S. EPA. Evaluation of Chlorine Dioxide Gas and Peracetic Acid Fog for the
Decontamination of a Mock Heating, Ventilation, and Air Conditioning Duct System. U.S.
Environmental Protection Agency, Washington, DC, EPA/600/R- 14/01 4, 2014.
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Ozone
31. U.S. EPA. Ozone Gas Decontamination of Materials Contaminated with Bacillus anthracis
Spores. U.S. Environmental Protection Agency, Washington, DC, EPA/600/R-11/142, 2011.
Sensitive Material Decontamination
32. U.S. EPA. Assessment of the Impact of Decontamination Fumigants on Electronic
Equipment. U.S. Environmental Protection Agency, Washington, DC, EPA/600/R-14/316,
2014.
CONTACT INFORMATION
For more information, visit the EPA Web site at http://www2.epa.gov/homeland-security-
research.
Technical Contact: Shawn Ryan (ryan.shawn@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.
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