Reference Documents on Relevant Chemicals

"There have been 4,581 reports of incidents associated with human exposure to sodium hypochlorite, calcium hypochlorite, or potassium hypochlorite reported in the OPP Incident Data System during the time period from 1973 to 2017. There were 29 reports of human related fatalities," " “The Agency has determined that the available acute toxicity data and fish and wildlife data are sufficient to address the acute toxicity risks to humans and the environment, and has concluded that there is no need for chronic or subchronic data to continue registering sodium and calcium hypochlorite products for the registered uses”"

"In pure water, chlorine gas forms a mixture of hypochlorous acid and hypochlorite. Hypochlorous acid is an oxidizing agent and is used in water treatment" "Chlorine dioxide has been cleared by the Food and Drug Administration as a chemical source for bleaching white (21 CFR 137.105) and wheat flour (21 CFR 137.200)."

"Relative density (water = 1): 1.6 (liquid, 0°C) Solubility in water, g/100ml at 20°C: 0.8 Vapour pressure, kPa at 20°C: 101 Relative vapour density (air = 1): 2.3 Explosive limits, vol% in air: >10 "

1999 "studies have shown that pH has much less effect on pathogen inactivationfor viruses and cysts with chlorine dioxide than with chlorine in the pH range of 6 to 8.5. Unlikechlorine, studies on chlorine dioxide have shown the degree of inactivation of poliovirus 1 (Scarpinoet al., 1979) and Naegleria gruberi cysts (Chen et al., 1984) increase as the pH increases." "In the first disinfection mechanism, chlorine dioxide reacts readily with amino acids cysteine,tryptophan, and tyrosine, but not with viral ribonucleic acid (RNA)). From this research, it was concluded that chlorine dioxide inactivated viruses by altering theviral capsid proteins. However, chlorine dioxide reacts with poliovirus RNA and impairs RNA synthesis. It has also been shown that chlorine dioxide reacts with free fatty acids. At this time, it is unclear whether the primary mode ofinactivation for chlorine dioxide lies in the peripheral structures or nucleic acids. Perhaps reactions inboth regions contribute to pathogen inactivation.The second type of disinfection mechanism focuses on the effect of chlorine dioxide on physiologicalfunctions. It has been suggested that the primary mechanism for inactivation was the disruption ofprotein synthesis (Bernarde et al., 1967a). However, later studies reported the inhibition of proteinsynthesis may not be the primary inactivation mechanism. A more recent studyreported that chlorine dioxide disrupted the permeability of the outer membrane). The results of this study were supported by the findings of Olivieri et al. (1985) and Ghandbari et al. (1983), which found that the outer membrane proteins and lipids were sufficiently altered by chlorine dioxide to increase permeability"

***** {Includes chart of residuals in treated foods} "While the chlorite ion is stable in aqueous solution, under acidic conditions, chlorite forms a semi-stable intermediate, chlorous acid (HClO2). Chlorous acid disintegrates to chlorine dioxide (ClO2), which further degrades to chlorite (ClO2 ̄) and ultimately chloride (Cl ̄) is formed. The extent of each of the degradation pathways and thus the proportion of each of the oxy-chlorine species depends in part on the pH of the solution. Other factors such as temperature and alkalinity of the water also affect the composition of the oxy-chlorine constituents." "At a pH of 2.3, approximately 31% of chlorite (from sodium chlorite) is converted to chlorous acid" "The pH values at different concentrations of citric acid, phosphoric acid, and sodium hydrogen sulfate to prepare a 1000 mg/l sodium chlorite solution are presented in Figure 1" "The technical-grade of sodium chlorite used to prepare ASC is comprised of 80% of sodium chlorite, with sodium chloride, sodium carbonate, sodium hydroxide, sodium sulfate, and sodium chlorate making up the remainer of the composition." "Although levels of chlorine dioxide do not exceed 3 ppm in the solution initially, chlorine dioxide levels increase during aging of the solution." "Chlorine dioxide... is not present as a residue of the treated food-product." "Instead, the ASC solution is monitored for sodium chlorite concentration and pH, which are known to result in acceptable levels of chlorate, chlorite, and chlorine dioxide. Depending on the food application, the solution is characterized by a sodium chlorite concentration in the range of 50-150 mg/l and a pH of 2.8-3.2 or 500-1200 mg/l and a pH of 2.5-2.9."

{OSHA CURRENT LIMITS} NIOSH REL: 0.1 ppm (0.3 mg/m3) TWA, 0.3 ppm (0.9 mg/m3) STEL. Current OSHA PEL: 0.1 ppm (0.3 mg/m3) TWA. 1989 OSHA PEL: 0.1 ppm (0.3 mg/m3) TWA, 0.3 ppm (0.9 mg/m3) STEL. 1993-1994 ACGIH TLV: 0.1 ppm (0.28 mg/m3) TWA, 0.3 ppm (0.83 mg/m3) STEL

****** 1972 {Cited by 282 papers}

2005

********* {Includes graph comparing contact time effects for differing dosages.} {Includes chart of level testing methods} {Includes comparison chart of commercial chlorine dioxide generator equipment} "...it is stable in dilute solution in a closed container in the absence of light. " "In drinking water, chlorite (ClO2-) is the predominant reaction endproduct, with approximately 50 to70 percent of the chlorine dioxide converted to chlorite and 30 percent to chlorate (ClO3-) and chloride (Cl-)" "educing the temperature from 20°C to10°C reduced the disinfection effectiveness of chlorine dioxide on Cryptosporidium by 40 percent,which is similar to previous results for Giardia and viruses." "At neutral pH levels, the required doses may be morethan 20 mg/L." "mostly viral aggregates took 2.7 times longer to inactivate with chlorine dioxide than single state viruses" "clumps of... cysts were more resistant to chlorine dioxide" " CT required for 2-log inactivation [of Naegleriagruberi cysts] was much higher than normally employed for water treatment" "In water treatment processes that require high pH, such as softening, chlorine dioxide should beadded after the pH has been lowered" "The occurrence of photochemical decomposition of chlorine dioxide can affect the ultimateconcentrations of chlorine dioxide, chlorite, and chlorate in water treated with chlorine dioxide" "[Sodium chlorite] 25 percent solution [as formulated commercially] may not require any special protection except in cold climates" "The reactions produce chlorite and chlorate as endproducts (compoundsthat are suspected of causing hemolytic anemia and other health effects)" "chlorinedioxide dosage cannot exceed 1.4 mg/L to limit the total combined concentration ofClO2, ClO2-, ClO3-, to a maximum of 1.0 mg/L. Under the proposed DBP regulations,the MRDL for chlorine dioxide is 0.8 mg/L and the MCL for chlorite is 1.0 mg/L"

1999. Chapter 4--Chlorine Dioxide. "The MRDL for chlorine dioxide is 0.8 mg/L and the MCL for chlorite is 1.0 mg/L per the D/DBP rule. This means that if the oxidant demand is greater than about 1.4 mg/L, chlorine dioxide may not be used as a disinfectant because the chlorite/chlorate ions byproduct, might exceed the maximum level allowed, unless inorganic byproducts (e.g., chlorite) are subsequently removed. There are numerous means to reduce excessive chlorite levels..."

****!!!!*** Current date. {There are likely some errors in this info} "PubChem CID 24870. Structure, chemical names, physical and chemical properties, classification, patents, literature, biological activities, safety/hazards/toxicity information, supplier lists, and more."

*****!!!!**** Current date. {Central page with many sub-linked documents}

*******!!!!****** (Current date) {Includes 20+ docs, including ones for 2006 RED}

****2018 Jan. {Very good technical info. Fumigation leaves no CD or by-product residue. Air treatments are more effective than Liquid. Includes several CD and SC trade names. Denied because of lack of public requests, available alternatives, etc.}

2004 Sept.

{Includes *chlorine.* Does this also include chlorine dioxide?}

2000 Sept. {Evaluating RfC, RfD, carcinogenicity. Includes **injection report.} "what exists in water or the stomach is a mixture of these chemical species (i.e., chlorine dioxide, chlorite, chlorate) and possibly their reaction products with the gastrointestinal contents." "[after gavage dosing of rats] it was not clear from these reports whether the parent chlorine dioxide itself or the chlorite, chlorate, or chloride ion degradation products were absorbed"

2009 Sept.

2000 Sept. "No studies examining the toxicity of inhaled chlorite were located,,,Under ambient conditions, airborne chlorite is likely to exist as a particulate, whereas inhalation exposure to chlorine dioxide is as a gas. Based on their physical and chemical properties, it is anticipated that inhaled chlorine dioxide and chlorite would have very different modes of exposure. Therefore, the potential hazards associated with exposure to these two chemicals are also very different."

The daily drinking water consumption for the 10 kg child and 70 kg adult are assumed to be 1 L/day and 2 L/day

2008 May ******* {in-depth info on concentrations, safety, efficacy & time for CD and other disinfectants} "The use of chlorine dioxide at 20 mg/l resulted in little or no difference in numbers of total aerobic bacteria on beef compared with using potable water. " "The reaction of the bromide ion (Br−) with chlorine dioxide is thermodynamically unfavourable. However, with intense sunlight and high concen-trations of chlorine dioxide, chlorine dioxide does oxidize the bromide ion to hypobromite (BrO−) and bromate (BrO3−)"

{Includes Chlorine Dioxide info.} "Chlorine dioxide kills microorganisms directly by disrupting transport of nutrients across the cell wall." "Chlorine dioxide is a very reactive compound and breaks down quickly in the environment (ATSDR, 259 2004a). In air, sunlight rapidly causes chlorine dioxide to break down into chlorine gas and oxygen. When 260 used as a disinfecting agent, however, the product of chlorine dioxide is primarily chlorite. Although 261 chlorite in water may move into groundwater, reactions with soil and sediments may reduce the amount of 262 chlorite reaching groundwater. The toxic action of chlorite is primarily in the form of oxidative damage to 263 red blood cells at doses as low as 10 mg/kg of body weight. Toxic reaction products are not known to 264 occur when chlorite is mixed with organic materials."

***** Current date. "Chlorine dioxide deodorizes because it can react with odorous substances (such as H 2 S, -SOH, -NH 2, etc.) and rapidly oxidize the odorous substances into other substances. Moreover, it can prevent the decomposition of methionine into ethylene, and can also destroy the formed ethylene, thereby delaying decay, killing microorganisms without reacting with fatty acids and not destroying the structure of food."

~2003. "Chlorine dioxide and chlorite (ions and salts) are strong oxidizers and react quickly in water or moist body tissues to form chloride ions. Consequently, chlorine dioxide and chlorite (ions and salts) are not detected in human tissues (e.g., blood, urine, fat, or breast milk). [Have some studies shown contradiction??]" " In water, chlorine dioxide is a strong oxidizer; **50–70%** of the chlorine dioxide that reacts with organic and inorganic compounds will immediately appear as chlorite (ClO2-) and chloride (Cl-) ions...chlorine dioxide does result in the formation of other DBPs (e.g., lower chlorinated organics, chlorate, and chlorite) which may be found in drinking water... ***Chlorine dioxide will decompose upon exposure to sunlight. The gas-phase absorption spectrum for chlorine dioxide is the same as in aqueous solution. The primary photochemical reaction of ClO2 in the gas phase corresponds to homolytic scission of one of the chlorine-oxygen bonds (i.e., ClO26ClO + O). Products of this initial reaction generate secondary products including doublet-state oxygen (O2*), chlorine (Cl2), and chlorine trioxide (Cl2O3) . If chlorine dioxide gas is diluted in air to below 15 volume percent, it can be relatively stable in darkness." "Chlorine dioxide alone will not hydrolyze in solution to any appreciable extent between pH 2 and 10. .." "Chlorite ions (ClO2-) are also effective oxidizing agents, although they react much slower than chlorine dioxide""Chlorine substitution in the products, however, is not entirely absent" "Under sunlight, some photolysis intermediates with long half-lives are capable of oxidizing bromide to from bromate."

*****This IRIS assessment for Chlorine dioxide consists of hazard identification and dose-response assessment data and provides support for EPA risk management decisions.

1991. {Includes toxicology data} from IARC Monographs on the Evaluation of Carcinogenic Risks to Humans, No. 52. IARC Working Group on the Evaluation of Carcinogenic Risks to Humans. Lyon (FR): International Agency for Research on Cancer. "Mouse: Groups of 50 male and 50 female B6C3F1 mice, six weeks old, were given 0.0, 0.025 or 0.05% sodium chlorite (82–87% pure [impurities unspecified]) in the drinking-water for 80 weeks. Survival at 85 weeks was: males—control, 35/50; low-dose, 47/50; high-dose, 43/50; females—control, 47/50; low-dose, 50/50; high-dose, 50/50."