Fogging of Chlorine-Based Sporicidal Liquids for the …...Fogging of Chlorine-Based Sporicidal...
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Test Facility Sporicidal Solution Active Ingredient pH-adjusted bleach (pAB) Sodium hypochlorite, hypochlorous acid Diluted bleach Sodium hypochlorite (~ 2% free avail. chorine) Stabilized chlorinating granules (dichlor) Sodium dichloro-s-triazinetrione Hydrated, hypochlorous acid Aqueous ClO 2 Aqueous chlorine dioxide Coupon Preparation Inoculation Fog Treatment Coupon Recovery Sample Processing Fogging of Chlorine-Based Sporicidal Liquids for the Inactivation of Bacillus anthracis Surrogate Spores in an Office Environment Stella McDonald 1 , Abderrahmane Touati 1 , and Joseph Wood 2 1 Jacobs Technology Inc., 2 U.S. Environmental Protection Agency National Homeland Security Research Center Stella McDonald l [email protected] l 919-541-5423 BACKGROUND TEST SEQUENCE & CONDITIONS DECONTAMINATION EFFICACY RESULTS Spray application of sporicidal liquids directly to surfaces contaminated with spores of Bacillus anthracis can be effective yet labor intensive, hazardous, and potentially generate large volumes of decontaminant waste solution. The use of fogging technology to disseminate sporicidal solutions has the potential to be a less arduous, more economical, and effective alternative for surfaces and volumetric decontamination for areas contaminated with B. anthracis. This investigation evaluated the efficacy of an off-the-shelf fogger using chlorine-based sporicidal liquids for decontaminating an office environment. ACKNOWLEDGEMENTS CHLORINE-BASED SPORICIDES SPORE AND LOADING The test surfaces were loaded with a target dose of 10 7 colony- forming units (CFU) of B. atrophaeus spores, using a metered-dose inhaler (MDI) actuator. B. atrophaeus is a proven surrogate for B. anthracis when using chlorine-based decontaminants. • All tests were conducted in 24 m 3 Consequence Management and Decontamination Evaluation Room, or COMMANDER, using a mock office set up. Test Sporicidal Solution Actual Sporicidal Solution Volume Disseminated (mL) AIC in Aqueous Solution (mg/L) pH Mean AIC in Chamber Air (ppm) Mean RH (%) Mean T (°C) Air Exchange (fraction of chamber volume replaced each hour) 1 pAB 887 6440 6.8 3 68 28 0 2 pAB 2921 6480 7.0 7 67 26 0 3 DB 2891 17401 11.4 8 77 28 0 4 pAB 3941 7840 6.8 7 64 27 0 6 DB 4840 16721 NA 10 42 28 0 7 Dichlor 5873 20601 NA 4 76 22 0 8 DB 5300 15920 12.01 27 64 26 0 9 pAB 5891 15701 7.20 35 69 26 0 10 ClO 2 1910 5906 2.04 59 72 25 0 11 ClO 2 3960 4763 2.24 73 96 24 0 12 pAB 5817 18301 6.67 89 97 28 0 13 Dichlor 7165 20701 7.82 12 91 28 0 14 B 7642 19001 11.14 34 100 26 0 15 ClO 2 7738 5907 1.66 36 90 26 0 16 pAB 7229 17401 6.24 131 80 27 0 17 DB 7776 24201 11.15 48 87 29 0 18 Dichlor 7915 21301 6.61 20 81 30 0 19 DB 7766 23701 11.12 46 90 27 0 20 pAB 7860 18701 6.28 52 68 26 0 21 DB 7780 23001 11.31 9 73 24 0 22 Dichlor 7778 21901 6.52 11 69 25 0.75 23 Dichlor 7396 20701 NA 14 84 25 0 24 Dichlor 3141 32502 6.74 8 56 27 0.75 25 Dichlor 5406 20801 6.57 9 65 27 0.75 26 DB 7674 22201 11.13 16 66 29 0.75 0.00 1.00 2.00 3.00 4.00 5.00 6.00 7.00 8.00 Test 7 Test 13 Test 18 Test 22 Test 23 Test 24 Test 25 Test 3 Test 6 Test 8 Test 14 Test 17 Test 19 Test 21 Test 26 Test 10 Test 11 Test 15 Test 1 Test 2 Test 4 Test 9 Test 12 Test 16 Test 20 Dichlor Diluted bleach ClO2 (aq) pAB Average Log Reduction • Coupons were collected, and spores were extracted, serial plated, filter plated (if needed) and enumerated as CFU • On average, 2.83E+07 (± 9.38E+06) CFU were recovered from coupon positive controls • Decontamination efficacy for each material for each test was expressed in terms of log 10 reduction (LR), based on the difference in the average CFU recovered from positive controls (not exposed to the fog) compared to average CFU recovered from test coupons • Biological indicators also used in most tests as another assay to assess efficacy MATERIAL SAMPLING Average Log Reduction by Material Average Log Reduction by Sporicide per Location Average Log Reduction by Location 0.00 2.00 4.00 6.00 8.00 Under the desk On the desk Above the ceiling All Locations Log Reduction Location -2.00 0.00 2.00 4.00 6.00 8.00 10.00 Ave. Log Reduction Material COUPON MATERIALS Eight materials used for this study were as follows: • Concrete • Painted wall board (PWB) paper • Ceiling Tile • Oak wood • Galvanized steel • Laminate flooring • Borosilicate glass • Carpet FOG EQUPIMENT We used an ultra-low volume fogger (SANI-TIZER™, Curtis Dyna-fog, Ltd., Westfield, IN). SAMPLE LOCATIONS 0.00 1.00 2.00 3.00 4.00 5.00 6.00 7.00 8.00 9.00 Carpet Ceiling tile Concrete Gal. metal Glass Laminate PWB Paper Wood Log Reduction Material Dichlor Diluted bleach ClO2 (aq) pAB Average Log Reduction by Sporicide Efficacy Comparison of Similar Tests with Different Rates of Air Exchange Efficacy Comparison for Tests with Varying AICs Decontamnation Efficacy Comparison of Similar Tests with Different Volumes of Disseminated Solution Three replicates of each the material placed under the desk, on the desk, and above the ceiling. • Temperature, relative humidity (RH), air pressures, and flow rates within the decontamination chamber were controlled and/or their data logged continuously using a supervisory control and data acquisition (SCADA) system. AIC= Active ingredient concentration (either Cl 2 or ClO 2 gas; DB= diluted bleach) SUMMARY • All materials were effectively decontaminated (≥ 6 LR) against the B. anthracis spore surrogate we used, in at least one test condition, except for carpet and ceiling tile. • Nonporous materials were easier to decontaminate; materials that were porous and/or comprised of organic chemical constituents proved more difficult to effectively decontaminate. • Galvanized metal, glass, laminate, and PWB were effectively decontaminated (≥ 6LR) in most tests. • Fogging of the chlorinated decontaminants was moderately effective for concrete and wood (3-5.99 LR), with only one test achieving an average ≥ 6 LR on concrete, but several tests in which ≥ 5 LR was achieved. • Maximizing the fogged solution quantity and the active ingredient concentration improved efficacy and produced similar results for all chlorine-based sporicides. • Average efficacy for all materials in these optimized tests was generally > 5 LR, independent of sporicide. • Coupons positioned on the desk showed significant yet minor improvement (~ 0.5 LR) in spore inactivation compared to their counterparts located in the areas under the desk and above the ceiling. • Dichlor produced a visible residue on materials, which would potentially require removal following its use. For their valuable input and guidance, we acknowledge the EPA advisory team: Worth Calfee, Shannon Serre, Leroy Mickelsen, Lukas Oudejans, Richard Rupert; as well as EPA QA staff: Eletha Roberts, Ramona Sherman. For their efforts in the laboratory, we acknowledge the following JTI folks: Christina Slone, Ahmed Abel-Hady, Denise Aslett, and Joshua Nardin. Cl 2 gas dosimeters were evaluated for use 0 20 40 60 80 100 120 2 3 4 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 Percent Inactivation Test ID Percent of BIs inactivated for each test (n=9) DISCLAIMER: The United States Environmental Protection Agency (EPA), through its Office of Research and Development’s National Homeland Security Research Center, funded, directed, and managed this investigation through contract number EP-C-15-008. This poster was peer and administratively reviewed and has been approved for presentation as an Environmental Protection Agency document. It does not necessarily reflect the views of the Environmental Protection Agency. No official endorsement should be inferred. This report includes photographs of commercially-available products. The photographs are included for purposes of illustration only and are not intended to imply that EPA approves or endorses the product or its manufacturer. EPA does not endorse the purchase or sale of any commercial products or services.
Transcript of Fogging of Chlorine-Based Sporicidal Liquids for the …...Fogging of Chlorine-Based Sporicidal...
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Test Facility
Sporicidal Solution
Active Ingredient
pH-adjusted bleach (pAB)
Sodium hypochlorite, hypochlorous acid
Diluted bleach Sodium hypochlorite (~ 2% free avail. chorine)
Stabilized chlorinating granules (dichlor)
Sodium dichloro-s-triazinetrione Hydrated, hypochlorous acid
Aqueous ClO2 Aqueous chlorine dioxide
Coupon Preparation
InoculationFog
TreatmentCoupon
RecoverySample
Processing
Fogging of Chlorine-Based Sporicidal Liquids for the Inactivation of
Bacillus anthracis Surrogate Spores in an Office Environment
Stella McDonald1, Abderrahmane Touati1, and Joseph Wood2
1Jacobs Technology Inc., 2U.S. Environmental Protection Agency National Homeland Security Research Center
Stella McDonald l [email protected] l 919-541-5423
B A C K G R O U N D
T E S T S E Q U E N C E & C O N D I T I O N S
D E C O N TA M I N AT I O N E F F I C A C Y R E S U LT SSpray application of sporicidal liquids directly to surfacescontaminated with spores of Bacillus anthracis can beeffective yet labor intensive, hazardous, and potentiallygenerate large volumes of decontaminant wastesolution. The use of fogging technology to disseminatesporicidal solutions has the potential to be a lessarduous, more economical, and effective alternative forsurfaces and volumetric decontamination for areascontaminated with B. anthracis. This investigationevaluated the efficacy of an off-the-shelf fogger usingchlorine-based sporicidal liquids for decontaminating anoffice environment.
A C K N O W L E D G E M E N T S
C H L O R I N E - B A S E D S P O R I C I D E S
S P O R E A N D L O A D I N G
The test surfaces were loadedwith a target dose of 107 colony-forming units (CFU) of B.atrophaeus spores, using ametered-dose inhaler (MDI)actuator. B. atrophaeus is aproven surrogate for B. anthraciswhen using chlorine-baseddecontaminants.
• All tests were conducted in 24 m3
Consequence Management and Decontamination Evaluation Room, or COMMANDER, using a mock office set up.
Test Sporicidal Solution
Actual Sporicidal Solution Volume
Disseminated (mL)
AIC in Aqueous Solution (mg/L)
pHMean AIC
in Chamber Air (ppm)
Mean RH (%)
Mean T (°C)
Air Exchange
(fraction of chamber volume
replaced each hour)
1 pAB 887 6440 6.8 3 68 28 0
2 pAB 2921 6480 7.0 7 67 26 0
3 DB 2891 17401 11.4 8 77 28 0
4 pAB 3941 7840 6.8 7 64 27 0
6 DB 4840 16721 NA 10 42 28 0
7 Dichlor 5873 20601 NA 4 76 22 0
8 DB 5300 15920 12.01 27 64 26 0
9 pAB 5891 15701 7.20 35 69 26 0
10 ClO2 1910 5906 2.04 59 72 25 0
11 ClO2 3960 4763 2.24 73 96 24 0
12 pAB 5817 18301 6.67 89 97 28 0
13 Dichlor 7165 20701 7.82 12 91 28 0
14 B 7642 19001 11.14 34 100 26 0
15 ClO2 7738 5907 1.66 36 90 26 0
16 pAB 7229 17401 6.24 131 80 27 0
17 DB 7776 24201 11.15 48 87 29 0
18 Dichlor 7915 21301 6.61 20 81 30 0
19 DB 7766 23701 11.12 46 90 27 0
20 pAB 7860 18701 6.28 52 68 26 0
21 DB 7780 23001 11.31 9 73 24 0
22 Dichlor 7778 21901 6.52 11 69 25 0.75
23 Dichlor 7396 20701 NA 14 84 25 0
24 Dichlor 3141 32502 6.74 8 56 27 0.75
25 Dichlor 5406 20801 6.57 9 65 27 0.75
26 DB 7674 22201 11.13 16 66 29 0.75
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Dichlor Diluted bleach ClO2 (aq) pAB
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• Coupons were collected, and spores were extracted, serial plated, filterplated (if needed) and enumerated as CFU
• On average, 2.83E+07 (± 9.38E+06) CFU were recovered from couponpositive controls
• Decontamination efficacy for each material for each test was expressed interms of log10 reduction (LR), based on the difference in the average CFUrecovered from positive controls (not exposed to the fog) compared toaverage CFU recovered from test coupons
• Biological indicators also used in most tests as another assay to assessefficacy
M AT E R I A L S A M P L I N G
A v e r a g e L o g R e d u c t i o n b y M a t e r i a l
A v e r a g e L o g R e d u c t i o n b y S p o r i c i d e p e r L o c a t i o n
A v e r a g e L o g R e d u c t i o n b y L o c a t i o n
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Under the desk On the desk Above theceiling
All Locations
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-2.000.002.004.006.008.00
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Material
C O U P O N M AT E R I A L S
Eight materials used for thisstudy were as follows:
• Concrete• Painted wall board (PWB)
paper• Ceiling Tile• Oak wood• Galvanized steel• Laminate flooring• Borosilicate glass• Carpet
F O GE Q U P I M E N T
We used an ultra-low volumefogger (SANI-TIZER™, CurtisDyna-fog, Ltd., Westfield, IN).
S A M P L E L O C AT I O N S
0.001.002.003.004.005.006.007.008.009.00
Carpet Ceilingtile
Concrete Gal.metal
Glass Laminate PWBPaper
Wood
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Dichlor
Diluted bleach
ClO2 (aq)
pAB
A v e r a g e L o g R e d u c t i o n b y S p o r i c i d e
Efficacy Comparison of Similar Tests with
Different Rates of Air Exchange
Efficacy Comparison for Tests with Varying AICs
Decontamnation Efficacy Comparison of Similar
Tests with Different Volumes of Disseminated
Solution
Three replicates ofeach the materialplaced under thedesk, on the desk,and above theceiling.
• Temperature, relative humidity (RH), air pressures, and flow rates within the decontamination chamber were controlled and/or their data logged continuously using a supervisory control and data acquisition (SCADA) system.
AIC= Active ingredient concentration (either Cl2 or ClO2 gas; DB= diluted bleach)
S U M M A R Y
• All materials were effectively decontaminated (≥ 6 LR) against the B. anthracis spore surrogate we used, in at least one test condition, except for carpet and ceiling tile.
• Nonporous materials were easier to decontaminate; materials that were porous and/or comprised of organic chemical constituents proved more difficult to effectively decontaminate.
• Galvanized metal, glass, laminate, and PWB were effectively decontaminated (≥ 6LR) in most tests.
• Fogging of the chlorinated decontaminants was moderately effective for concrete and wood (3-5.99 LR), with only one test achieving an average ≥ 6 LR on concrete, but several tests in which ≥ 5 LR was achieved.
• Maximizing the fogged solution quantity and the active ingredient concentration improved efficacy and produced similar results for all chlorine-based sporicides. • Average efficacy for all materials in these optimized tests was generally > 5 LR, independent of sporicide.
• Coupons positioned on the desk showed significant yet minor improvement (~ 0.5 LR) in spore inactivation compared to their counterparts located in the areas under the desk and above the ceiling.
• Dichlor produced a visible residue on materials, which would potentially require removal following its use.
For their valuable input and guidance, we acknowledge the EPA advisory team: Worth Calfee, Shannon Serre, Leroy Mickelsen, Lukas Oudejans, Richard Rupert; as well as EPA QA staff: Eletha Roberts, Ramona Sherman.For their efforts in the laboratory, we acknowledge the following JTI folks: Christina Slone, Ahmed Abel-Hady, Denise Aslett, and Joshua Nardin.
Cl2 gas dosimeters were evaluated for use
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Test ID
Percent of BIs inactivated for each test (n=9)
DISCLAIMER: The United States Environmental Protection Agency (EPA), through its Office of Research and Development’s National Homeland Security Research Center, funded, directed, and
managed this investigation through contract number EP-C-15-008. This poster was peer and administratively reviewed and has been approved for presentation as an Environmental Protection Agency
document. It does not necessarily reflect the views of the Environmental Protection Agency. No official endorsement should be inferred. This report includes photographs of commercially-available
products. The photographs are included for purposes of illustration only and are not intended to imply that EPA approves or endorses the product or its manufacturer. EPA does not endorse the purchase
or sale of any commercial products or services.
