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technical BRIEF
BUILDING A SCIENTIFIC FOUNDATION FOR SOUND ENVIRONMENTAL DECISIONS
Surface Decontamination Efficacy Studies for
Chemical Warfare Blister Agents
Purpose
Blister agents, or vesicants, are contaminants of concern due to their recent suspected use in the
Middle East [1], Because these agents persist on surfaces, it is critical to have effective
decontamination methods. This brief provides a summary of recent U.S. Environmental
Protection Agency (EPA) studies evaluating the efficacy of various decontamination methods
against blister agents on surfaces. Results of bench-scale tests that assessed four
decontamination solutions against three blister agents applied to building materials are
discussed. This overview provides decision-makers with practical information on surface
decontaminations options during a blister agent response.
Introduction
EPA is the primary federal agency responsible for remediation of indoor and outdoor areas in
which chemical agents are released. Therefore, In support of EPA's mission in this area, EPA's
Homeland Security Research Program conducts research to help responders and decision-makers
minimize environmental impacts and human health effects following the release of a chemical
agent. Limited data exist on decontamination approaches that neutralize the vesicant properties
of blister agents. EPA conducted bench-scale studies to evaluate several decontaminants for
their efficacy against the chemical warfare blister agents Lewisite (L), sulfur mustard (HD), and
Agent Yellow (HL) (a mixture of L and HD) on a variety of building materials. Some of the studies
also evaluated the formation of residual vesicant decontamination by-products that remained
after decontamination.
Persistence of Blister Agents
Sulfur mustard and Lewisite are semi- and low to moderate- persistent chemical warfare agents,
respectively [2,3] with liquids on surfaces likely to last hours to days for both agents. Persistence
of the neat agents is known to be dependent on material type and environmental conditions and
should be considered in the overall remediation objectives. The studies in this brief measured
agent amounts removed through natural attenuation processes (e.g., evaporation, degradation
and other physical or chemical interactions) at 60 or 90 min following contamination and those
results are reported as "No Decon".
U.S. Environmental Protection Agency
Office of Research and Development, Homeland Security Research Program
September, 2016
EPA/600/S-16/275, 2017
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Experimental Methods
Decontamination studies were conducted using approximately 10 cm2 coupon materials (i.e.,
an excised sample) held at room temperature. For each study, a 30 min contact time between
the surface material and the blister agent prior to decontamination solution application was
included. Residual amounts of blister agent HD as extracted from coupons were determined by
gas chromatography/mass spectrometry (GC/MS). Quantification of residual amounts of L
required a derivatization step to allow detection by conventional GC/MS [3,4].
Decontamination Products and Application Procedures
The bench-scale studies reviewed in this brief tested four decontaminants with varying contact
times. All decontamination studies summarized in this brief started at 2-5 g/m2 surface
concentrations.
• Bleach (full strength): K-O-K® Regular Bleach (5.25% sodium hypochlorite; Columbus, OH)
for HD decontamination testing; Clorox® (4-6% sodium hypochlorite; Oakland, California)
for L decontamination testing; and Fisher Scientific sodium hypochlorite (5.65-6%;
Pittsburgh, PA) for HL decontamination testing
• Dilute bleach: 1/10 dilution of Fisher Scientific sodium hypochlorite with deionized water
• Hydrogen peroxide solution - 3% (HP3%): Fisher Scientific
• EasyDecon® DF200 (DF200): prepared per manufacturer's instructions; ingredients listed
in manufacturer's Safety Data Sheet that are mixed to produce DF200 include benzyl-C12-
C16 alkyl dimethyl chlorides, hydrogen peroxide, and diacetin
The decontaminants were applied to building materials including wood (fir or pine plywood),
clear (uncoated) window glass, galvanized metal (industry HVAC standard 24 gauge; 0.7
millimeter [mm] thickness), and epoxy sealed concrete. It is important to note that multiple
studies were performed and not all combinations of material, decontaminant, and reaction time
could be compared between neat and mixed blister agents.
Figures 1 and 2 show the percent of blister agent (measured as HD or L) that is removed through
natural attenuation only ("No decon") and by neutralization on the surface through chemical
interaction with the decontaminant. Two interaction (dwell) times (30 min and 60 min) between
chemical agent on surface and decontaminant were considered.
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Wood
No Decon
Diluted Bleach I
—
Bleach I
HP 3%
I
Metal
a
f
Glass
| 30 min dwell time
160 min dwell time
NOT INCLUDED
NOT INCLUDED
0 20 40 60 80 100 0 20 40 60 80 100 0 20 40 60
100
Percent HD removed from coupon
Wood
Metal
Glass
No Decon
Diluted Bleach
Bleach
HP 3%
NOT INCLUDED
NOT INCLUDED
NOT INCLUDED
NOT INCLUDED
NOT INCLUDED
NOT INCLUDED
30 min dwell time
60 min dwell time
0 20 40 60 80 100 0 20 40 60 80 100 0 20 40 60 80 100
Percent L removed from coupon
Figure 1: Natural attenuation (no decontamination activity) and decontamination solution results
against blister agents on building materials for two dwell times (30 and 60 min). Top panel: HD;
Bottom panel: L, when applied as neat agent. (DF200 and sealed concrete were not part of the test
matrices for neat HD and L.
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Wood Metal Glass S Concrete
No Decon
30 min dwell time
60 min dwell time
Diluted Bleach
Bleach
No 30 min data recorded
No 30 min data recorded
Percent removal of HD from HD/L mixture from surface
No Decon
Diluted Bleach
Bleach
HP 3%
DF-200
Wood
0 20 40
Metal
Glass
S Concrete
30 min dwell time
60 min dwell time
80 100 0 20 40
80 100 0 20 40
80 100 0 20 40
Percent removal of L from HD/L mixture from surface
Figure 2: Natural attenuation (no decontamination activity) and decontamination solution results against blister agent mixture HL for two
dwell times (30 and 60 min) on building materials. Top panel: Amounts of HD recovered. Bottom panel: Amounts of L recovered
U.S. Environmental Protection Agency
Office of Research and Development, Homeland Security Research Program September, 2016
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Summary
Table 1 lists a summary of surface decontamination technologies evaluated by EPA. The table
reviews the decontamination efficacy findings associated with each decontaminant, and several
elements that should be considered such as availability of the decontaminant, ease of
use/application of the decontaminant, and material compatibility (damage such a corrosion due
to application of the decontaminant). Lewisite is an organoarsenic compound. Any L degradation
or attenuation will require removal of toxic residual arsenic from any surface.
Table 1. Chemical Warfare Blister Agent Surface Decontamination Technologies evaluated by EPA.
Decontaminant
Availability and Ease of
Use
Findings/Results
Material
Compatibility
Reference
#(s)
Natural
Attenuation
Requires (long term)
monitoring of
contaminated area. Entails
less effort to implement
than surface
decontamination options.
Personal protection
equipment (PPE) required.
Amounts recovered vary with
time and by material, both for HD
and L with L more persistent than
HD. Degradation of HD in air on
the tested surfaces does not
result in formation of toxic HD
by-products.
No material
incompatibility
2, 3, 4, 5
Bleach (full
strength)
Readily available as
household bleach.
Relatively easy application
when using low pressure
off the shelf commercial
sprayer; PPE required.
Full-strength bleach was the most
effective of four decontaminants
at reducing the amount of HD
(both applied as neat and as part
of HL) from coupons. Wood is
more difficult to decontaminate
with bleach. No toxic HD
degradation products were
detected.
Amounts of L recovered following
bleach application was near or
below detection limit for L.
Showed slight
discoloration
(lightening) of
the wood. [3]
There were no
other obvious
visible changes
to any of the
coupons. [4,5]
2, 3, 4, 5
Dilute Bleach
Readily available as
household bleach.
Relatively easy application
when using low pressure
off the shelf commercial
sprayer; PPE required.
Limited or no efficacy against HD
from HL after a 30-min dwell time
on wood, glass, and metal when
compared to natural attenuation.
Not evaluated for decon of neat
L.
Reduced recovered amount of L
from HL by more than 92% after
a 30-min reaction time on wood,
glass, and metal. A longer
reaction time did not improve
efficacy appreciably.
After decontamination of metal,
a small amount of toxic HD
There were no
obvious visible
changes to any
of the
coupons. [3]
2,3
U.S. Environmental Protection Agency
Office of Research and Development, Homeland Security Research Program
September, 2016
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Decontaminant
Availability and Ease of
Use
Findings/Results
Material
Compatibility
Reference
#(s)
degradation by-product mustard
sulfone was detected.
More residual L was observed
after treatment with dilute
bleach than with the other three
decontaminants.
HP3%
Readily available.
Relatively easy application
when using low pressure
off the shelf commercial
sprayer; PPE required.
HP3% did decrease the amount
of HD recovered from coupons
more than natural attenuation,
but substantial amounts of HD
remained on all materials. Toxic
HD by-products (mustard
sulfone) were generated by
hydrogen peroxide treatment.
HP3% does reduce Lto levels
near detection limit, both when
applied as neat L and as L from
HL
There were no
obvious visible
changes to any
of the
coupons. [4]
2, 3,4
DF200
Available from multiple
sources in the U.S.
Follow vendor
specifications for
application procedures.
Can be applied as liquid
and as foam (not
evaluated).
DF200 did decrease the amount
of HD (applied as HL) recovered
from wood and glass coupons
more than natural attenuation
(did not decrease the amount on
metal), but substantial amounts
of HD remained on some
materials. No toxic HD
degradation products were
detected.
Amounts of L recovered following
DF200 application was near or
below detection limit for L
(applied as HL).
There were no
obvious visible
changes to any
of the
coupons. [3,4]
2, 3,4
DF200: EasyDecon®; HP3%: 3% hydrogen peroxide solution; N/A: Not Applical
ble
Conclusions
The effectiveness of the tested surface decontaminants was found to depend on agent, material,
and decontaminant. Table 1 summarizes findings for the four decontaminants tested: full
strength bleach, dilute bleach, HP3%, and DF200. Below are additional general findings and
decontamination cautions.
General Findings for HD
• An increased decontaminant reaction time (60 min rather than 30 min) resulted in increased
efficacy for HP3%. Generally minimal or no impact on efficacy as a function of reaction time
was observed for the other decontaminants tested.
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• Only very low levels of toxic by-products were observed with the decontaminants tested. The
observed HD oxidation by-product is susceptible to further degradation by hydrolysis with
water and should not be a persistent hazard [2]. Formation of toxic by-products may be
further reduced when sufficient decontaminant is available.
General Finding for L
• All four decontaminants were effective at eliminating L to the detection limit level from all
tested surfaces.
• Decontamination of L or HL will always leave arsenic as a toxic metal on a surface, which must
be dealt with as to minimize its adverse health effects.
General Decontamination Cautions
• Decontamination reaction rates are in general temperature dependent. Application of any
of these decontaminants at lower temperatures, for example, are likely to result in different
(lower) efficacies.
• Presence of dirt or grime can impact the performance of a decontaminant due to the possible
degradation of the neutralizing active ingredient with the dirt and/or grime.
• The material that is contaminated has a significant effect on observed decontamination
efficacy. The porosity of the material is likely to be an important characteristic, as in wood.
Any possible reactivity of the surface material with the decontaminant may also impact the
overall efficacy.
• Hypochlorite in bleach degrades over time. This should be considered in an actual response
where bleach products may be applied without verification of actual hypochlorite
concentration.
While EPA studies were conducted on a bench-scale, the tactical procedures for decontaminating
a wide- area contaminated with blister agents are limited and knowledge gaps exist. However,
recommendations can be made by extrapolating experimental findings from the lab to the field.
The decontamination approach chosen for a particular surface may need to be evaluated in the
field (at pilot scale or within a small zone) and refined as necessary during the course of the
response until the desired effectiveness and process-knowledge is established for wide-scale
applications. Additionally, decision makers will need to consider the available resources, cost,
waste production, and the available waste management options before selecting a method.
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-G16C-00690. This summary has been subjected to the Agency's review and
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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. OPCW Executive Council gravely concerned about continuing use of chemical weapons in
Syria https://www.opcw.org/fileadmin/OPCW/EC/M-50/en/ecm50dec01 e .pdf Last
accessed October 31, 2016.
2. Stone, H., See, D., Smiley, A., Ellingson, A., Schimmoeller, J., Oudejans, L. Surface
decontamination for blister agents Lewisite, sulfur mustard and agent yellow, a Lewisite and
sulfur mustard mixture. Journal of Hazardous Materials vol. 314, 2016, pp. 59-66.
3. U.S. EPA. Decontamination of Agent Yellow, a Lewisite and sulfur mustard mixture.
Washington, D.C.: US Environmental Protection Agency. EPA/600/R-14/436, 2015.
4. U.S. EPA. Decontamination of Lewisite using liquid solutions: Neutralization and arsenic
removal. Washington, D.C.: U.S. Environmental Protection Agency. EPA/600/R-14/119, 2014.
5. U.S. EPA. Evaluation of household or industrial cleaning products for remediation of chemical
agents. Washington, D.C.: U.S. Environmental Protection Agency. EPA/600/R-11/055, 2011.
Contact Information
For more information, visit the EPA website at http://www2.epa.gov/homeland-security-research
Technical Contact: Lukas Oudejans ()udejans.Iukas@epa.gov)
General Feedback/Questions: Kathy Nickel (nickel.kathy@epa.go )
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 underthe
National Response Framework, statutory requirements, and Homeland Security Presidential Directives.
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