Chemical & Biological Dynamics

{Exspor & Clidox CD} "Chorine dioxide is not only a potent sporicide when used in aqueous solution, but has also been shown to be 1,075 times more sporicidal than ethylene oxide gas when used in the gaseous state1, a trait Dr. Trexler considers essential for any sporicide used in Gnotobiotics because air bubbles can become trapped below liquids" "0.007%. The stoichiometry of the reaction of the Clidox-S® base (sodium chlorite) with the Clidox-S® activator (hydroacetic acid) shows that even if every single molecule of the 0.85% sodium chlorite in the Clidox-S® base were converted completely to chlorine dioxide, it would still not generate the 3% (30,000 ppm) of chlorine dioxide cited." "the role of biological burden should have been given more consideration. What is the probability that a million spores would fall from the ambient air into an entry port during the brief time it is open? With an exposure time of mere minutes, one would undoubtedly be challenged with no more than 10 to a 40 viable dust particles and about 1 to 4 of them would be sporeforming species"

****!!!!****!!!!**** {ICA TriNova} "method for treating an object with chlorine dioxide gas, comprising contacting the object with chlorine dioxide gas while exposing the object to less than 1000 lux of light. The disclosed method minimizes chlorine containing residue on the surface of the object. The object can be a raw agricultural commodity (RAC) such as a raw fruit or vegetable." "Residues on the walls of each jar were quantitatively recovered by washing the walls sequentially with 4-50 mL aliquots of nanopure water and combining the aliquots with additional water to bring the total volume to 250 mL. These washings were analyzed by ion chromatography for chlorate and perchlorate ions. Based on reaction profiling of these particle mixtures, the weights of the particles provided within the TYVEK sachets were adjusted so that, upon reacting, a total of 1.6 mg of ClO2 would have been produced in each jar during the 2 hour period. " "Gas Chamber Studies Show Chlorate and Perchlorate Ions can be Minimized and in the Case of Perchlorate Eliminated when Fumigation is Performed in the Substantial Absence of Light when RACs are Present" "At 120 minutes, chlorine dioxide concentrations... fell well below expected concentrations, likely due to system leaks or to chlorine dioxide reacting with the exposure chambers themselves or with the silicone sealant used on the tanks. When tomatoes were present in the treatment chambers, chlorine dioxide gas was measurable only through 30 minutes for two replicates and through 60 minutes for one replicate. These data clearly indicate that tomatoes acted as a chlorine dioxide sink, consistent with studies using radiolabel showing the propensity for chlorine dioxide consumption by biologic materials, especially those tissues with a porous surface"

****!!!!****!!!!**** " Nearly all AZTD samples completely decontaminated • Greater than 6 LR for topsoil at 1 cm depth, 2 hour, both RH levels • 2 cm topsoil much more difficult to decon" "Aqueous ClO2 completely ineffective ( 0.5 LR) at most robust test conditions (4000 ppm, 2 hr contact Time, 4 spray applications)"

****!!!! "Adding salt to the aqueous solution used to produce sterilant allows humidity control, which improves kill of bacterial spores" "• Indicator to show ClO2 is present: • Indicator is printed on or attached to inside of pouch • Changes color on exposure to ClO2" "Reversible indicator on outside of sterilizer bag to show when unit is too cold and should be warmed for correct functioning" "To eliminate bacterial spores, it is highly desirable to control the humidity during sterilization to 70 to 95%, preferably 90 to 95%. Adding NaCl to the NaClO2 solution lowers the humidity of the gases produced from 100% to the desired range."

"The results show that dimethyl trisulfide and isoprene were substantially degraded into other by-products, including methane sulfonyl chloride and sulfur dioxide, during oxidation by chlorine dioxide and ozone, respectively. In contrast, 1-bromopropane, 2,3-butanedione and 1,1,2-trichloroethane have slow reaction kinetics and did not break down completely. Degradation of dimethyl trisulfide by chlorine dioxide and ozone follows the second order kinetics with half-lives of 2.2 min and 24 min, respectively. On the other hand, isoprene follows the first order reaction kinetics with rate constants of 0.4051 min-1 and 0.02244 min-1 and half-lives of 1.73 min and 32 min for degradation using ozone and chlorine dioxide, respectively. iv The oxidative degradation of 1-bromopropane, dimethyl trisulfide, and 2,3-butanedione by chlorine dioxide were more efficient than their reactions with ozone. However, the degradation of isoprene and 1,1,2-trichloroethane showed a greater reactivity toward ozone compared to chlorine dioxide. Most of the reaction products of oxidative degradation such as acetone, ethanol, formic acid, and dimethyl ether are chemically benign. But there are also by-products such as methane sulfonyl chloride, sulfur dioxide, chloroform, and cyanogen bromide that require further toxicological study."

****!!!!****!!!!**** {Includes data table of studies of gas and liquid against specific pathogens on food} "ClO2 disinfects by oxidation through the one-electron transfer mechanism, resulting in a reduction to ClO2–...The inactivation may be reached by allowing permeability of the cell membrane by changing the configuration of lipids and protein which involve the oxidation of amino acids by the gas. The second option is due to the reaction with nucleic acid and/or protein structures... However, some research showed degradation in viral RNA, inducing genotoxicity or discontinuing replication of genome information." "At higher relative humidity, a greater reduction of pathogen population was reported. This might be explained due to the increment of the pores’ sizes in the bacteria due to swelling at high humidity, which allow penetration of the ClO2 molecule into the bacteria." "Gaseous ClO2 showed a negative impact on treated fruits and vegetables through enzymatic browning formation... is related to the deterioration of nutritional quality. However, additional treatments can be added to the gas exposure to inhibit browning..." "negative color change in spinach leaves, which occurred during storage after being exposed even to 50 ppm of gaseous ClO2. Also, treatments with higher concentrations may lead to bleaching of fruits and vegetables" "reaction rate was estimated to be... which is significantly higher than the reaction rate reported by previous researchers ... the chamber used here was stainless steel... likely increased the reaction with the walls, and created minor corrosion" "larger exposure surface area for the water in contact with the gas increased the overall decay rate" "some crevices in equipment could impact the effectiveness of the ClO2 gas treatment due to the time for gas to diffuse into the crevice" "the ClO2 gas concentration is surface area- and water volume-dependent" "Results showed an increase in the reaction rate due to water presence at different water volume and exposure surface area. After 7 days’ exposure at 3000 ppm of ClO2 gas, none of the selected plastics or elastomers showed a significance difference (p0.05) in the hardness value." "excitation wavelengths of ClO2 are near the ultraviolet and visible light... leads to dissociation into ClO + O or Cl + O2" " Further research can also be extended to determine the rate of ClO2 molecules dissolving into water, and the residuals form."

****!!!!**** (2019) {Instructions (some of which probably need changes/corrections) for many uses. Also, lists of pathogens affected, with linked studies.} Vapor for Disinfection & Mold Elimination: 1 Gram Chlorine Dioxide per 1 square feet (w/10’ ceilings) [Researcher calcs: (0.28 m3). =3,571 mg/m3=1,275 ppmV in air], 3 to 24 hours – depending on issue severity of issue *****Concentrations to use for many applications****chart below shows how well ClO2 performs against alternatives. (other disinfectants)** Pathogens lisr with studies references **RECOMMENDED SPECIFICATIONS FOR CONTAINERS USED WITH CLO2 PRODUCTS...wear a NOISH/MSHA-approved respirator under the following conditions..." "Initial or remedial treatment... DECORATIVE AND ORNAMENTAL FOUNTAINS... Achieve a 5 ppm solution RESIDUAL concentration" "Continuous treatment... between 0.25 ppm and 0.5ppm"

****!!!!****!!!!***** "An aqueous solution of ClO2 at 126 ppm (w/w) for 15 s was effective, and no surviving virus was detected with the hemagglutination test. ClO2 gas at 5 ppm (v/v) sustained for 1 h inactivated the virus effectively, while at 2.5 ppm for 1 h only partially inactivated the virus."

****!!!!****!!!!****!!!! "Novel Technology to Reduce Risk of Viral Transmission in Enclosed Occupied Environments and Room Disinfection in Unoccupied Spaces, METSS Corporation: ... development of a novel chlorine dioxide (ClO2) gas dispersion system under a current EPA-sponsored Phase II SBIR project...). The system design offers a safe and effective means to rapidly generate ClO2 vapor for on-site room decontamination in hospital and non-hospital settings. This technology is intended to meet the demands of health care markets committed to decontaminate porous materials and sensitive equipment in rooms or vehicles used for care or transport of Ebola-exposed patients... current COVID-19 pandemic has demonstrated a clear need for technologies aimed at occupied spaces to reduce or prevent the spread of transmissible diseases through air or contact with surfaces contaminated with infectious microdroplets." "y. During repeated trials, METSS demonstrated the efficacy of low level ClO2 against Pseudomonas aeruginosa, Staphylococcus aureus, and Klebsiella pneumoniae. Additional efficacy testing was performed using MS2 (non-enveloped) and Phi6 bacteriophage (enveloped) as surrogates to SARS-CoV-2 and other human viruses...." "Decontamination of Covid-19 Vaccine Production Facility: ...a study completed within the United States Pharmaceutical Industry alongside ClorDiSys Solutions, Inc established evidence that chlorine dioxide gas has the capacity to inactivate beta-lactams" "t to achieve a 3-log reduction of beta-lactams, an inactivation cycle consisting of a 30-minute conditioning phase at 75% relative humidity, followed by an exposure to chlorine dioxide gas of at least 7,240 ppm-hours, is required. Chlorine dioxide destroys the beta-lactam ring and inactivates the compound, in similar fashion to the manner in which penicillin-resistant organisms act" "exposing the target beta-lactam to Chlorine dioxide gas at a concentration of 5mg/L" "Outdoor Systems Trial Using Full-Scale Agricultural Equipment for Wide Area Decontamination of Bacillus anthracis Surrogate Spores": ...we exploited state-of-the-art spray application technologies and formulation chemistry used in the agricultural industry, spore germination techniques and a novel decontaminant based on the targeted release of chlorine dioxide. Spores of B. thuringiensis HD-1 cry- were employed as a surrogate for virulent B. anthracis. However, key performance attributes were validated against a range of virulent B. anthracis. Preferred formulations for decontamination were developed through laboratory, environmental chamber, windtunnel and finally full-scale outdoor trials. During outdoor trials we achieved all essential success criteria on all surface types (4-Log10 reduction on wood, steel and cement). Results using steel surfaces approached that required for desirable performance (6-Log10 reduction). Significant loss of spore viability was found by environmental exposure alone (up to 3-Log10 over 72 h). However, active decontamination was more effective (up to a further 3.6-Log10 reduction in viable spores). Pre-germination before decontamination with chlorine dioxide was not found to have a benefit." "Use of Innovative Packaging to Facilitate On-Site Treatment of Waste from a Bacillus anthracis Release Incident: ...These semi-permeable materials would allow gaseous fumigants such as chlorine dioxide (ClO2) to pass into the bags but would not allow residual spores to penetrate the walls of the bags and exit into the atmosphere. Testing is currently occurring... to assess the ability of the materials to allow ClO2 to penetrate through the bag material and... to provide sufficient concentration-time exposure of the waste inside the permeation chamber"

****!!!!****!!!!*** (2011) "degradation rate of chlorine dioxide with the same initial mass concentration decreased gradually under uv, sunlight, 254 nm uv and 400-700 nm fluorescence, respectively, and the degradation rate of chlorine dioxide with the same initial mass concentration increased with the increase of gas mass concentration when the temperature varied from 15 to 25°c. therefore, the wavelength that plays a major role in the photodegradation of chlorine dioxide is ultraviolet light near 365 nm; the temperature has little effect on its degradation rate; under sunlight exposure, the degradation rate of chlorine dioxide is proportional to the first square of mass concentration, which belongs to the primary reaction, and its half-life is not related to the initial mass concentration, only related to the reaction rate constant k, and the half-life is about 63 min."

****!!!!**** "WHITE PAPERS, AND APPLICATION NOTES"

****!!!!****!!!!*** (2015) ***"A methodology is proposed for quantifying the amount of ClO2 gas needed in a package and/or treatment chamber." "The diffusion coefficient was found to be 0.129, 0.145, 0.173 cm2 s−1 at 5, 23, and 40 °C, respectively. Degradation of ClO2 gas under dark, UV-A and fluorescent lamp exposure was found to follow a first-order reaction. Degradation using a 40 W UV-A lamp was approximately four orders of magnitude larger than with a 34 W fluorescent lamp." "ClO2 gas can also be converted to chlorite and then react with oxygen changing their chemical structure, mobility, and properties" "Normally, the antimicrobial activity of gaseous ClO2 increased with a longer treatment time, especially at a low treatment temperature"

****!!!!**** {Includes novel approach for using chlorine dioxide to spray area, as classified for stored potable water} "certified organic by OMRI and Kosher by OU." "Oxine may be used as a primary water disinfectant in municipal water at levels of 0.5 ppm and in stored potable water at levels of 5.0 ppm." "Bacterial, mold and odor control is easily restored by an initial application of activated Oxine, from 200 to 500 ppm, depending on the severity of the problem, sprayed onto the wall and floors. Follow this initial application with a periodical maintenance dosage of 100 ppm unactivated" "The filler head assemblies are considered food contact surfaces..." ***** "Low dose applications of Oxine, misted onto the filler assembly during short scheduled breaks in the production day, have proven to be of considerable benefit."

{Significant info on Chlorine Dioxide use, particularly against anthrax} "1994 study by Roberts and Reymond wherein vitro tests on Mucor piriformis, Botrytis cinerea, Penicillium expansum, and Cryptosporiopsis perennans were conducted. Conidial suspensions of each pathogen were pipetted into test tubes containing ClO2 at concentrations of 1, 3, and 5 mg/l. Samples were drawn at 30 second intervals and the number of viable colony forming units/ml (CFU) was determined. The resultsof the tests are presented in Table 3.2-7."

*****!!!!**** {This article only mentions chlorine dioxide effectiveness against SARS-CoV-1, not SARS-CoV-2, against which it has greater effectiveness} "The exposure of SARS-CoV-2 (7.8 of log10 (TCID50/ml) to 1:49 (~150 ppm) and 1:99 (~75 ppm) *household bleach* resulted in the virus titer being reduced below levels of detection after 5 min" "The aim of this review is to provide information, primarily to the food industry, regarding a range of biocides effective in eliminating or reducing the presence of coronaviruses from fomites, skin, oral/nasal mucosa, air, and food contact surfaces. As several EPA approved sanitizers against SARS-CoV-2 are commonly used by food processors, these compounds are primarily discussed as much of the industry already has them on site and is familiar with their application and use. Specifically, we focused on the effects of alcohols, povidone iodine, quaternary ammonium compounds, hydrogen peroxide, sodium hypochlorite (NaOCl), peroxyacetic acid (PAA), chlorine dioxide, ozone, ultraviolet light, metals, and plant-based antimicrobials. This review highlights the differences in the resistance or susceptibility of different strains of coronaviruses, or similar viruses, to these antimicrobial agents."

"Its efficacy is largely not affected by pH and organic matter and it does no react with nitrogen compounds to form chloramines. The most widely accepted antimicrobial mechanism of ClO2 is damage to protein synthesis and increased permeability of the outer cell membrane. ClO2 gas may be more effective for inactivation of foodborne pathogens than aqueous ClO2 due to its penetration ability. Also, ClO2 gas could be applied for microbial control during transportation and storage of food." "The specific objectives of this study were, (ⅰ) to investigate the effect of relative humidity, surface characteristics of samples, and temperature on the antimicrobial efficacy of ClO2 gas... on produce and food contact surfaces, (ⅱ) evaluate the antimicrobial effects of the combination treatment of ClO2 gas with ultraviolet (UV) radiation, aerosolized sanitizer, and dry heat against foodborne pathogens on produce and seeds, (ⅲ) develop portable sustained release formulation of ClO2 gas for field application." "Combined treatment of ClO2 gas (10 ppmv) and aerosolized PAA (80 ppm) for 20 min caused 5.36, 5.06, and 4.06 log reductions of E. coli O157:H7, S. Typhimurium, and L. monocytogenes, respectively."

CHLORINE DIOXIDE FOR HOUSEHOLD USES

As chlorine dioxide gas is intended only for the uses specified...air releases are expected to be negligible. Using SMT’s method of chlorine dioxide production, the only potential release of chlorine dioxide to the atmosphere is by off-gassing from process water. As a result, air releases from the use of chlorine dioxide as proposed in this FCN are expected to be far below the 3 ppm residual. Small amounts of the FCS which were to volatilize out of solution would rapidly decompose. Unlike chlorine dioxide gas in-solution, which decomposes into various oxychloro species upon its exposure to water, ***gaseous chlorine dioxide will decompose into only chlorine and oxygen*** when released to the atmosphere... Chlorine dioxide undergoes a reduction to chloride, chlorite, and chlorate ions as it is exposed to organic matter. Additionally, chlorine dioxide often reduces to chlorine and oxygen when exposed to ultraviolet radiation, and from there it is likely to degrade into chloride ions.