*****!!!!****!!!** {Includes long list of research studies; regulations searches; patents; products from a broad range of manufacturers, and ingredients; etc}

2009 Sept.

Nov 1990 thru Oct 2000. {Safety levels for people}

********2021

{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

*********** Going into effect in 2021****

2003

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

~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."

{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."

Aug 2006. "Readers are referred to USEPA (2000a) for a detailed review of the effects seen at specific concentrations and exposure durations along with the derivation of the RfC."

2004 Sept. ********No reports were located in which gastrointestinal, musculoskeletal, endocrine, dermal, or metabolic effects were associated with inhalation exposure of humans or animals to chlorine dioxide or chlorite. *******Example concentrations: 150 ppm (420 mg/m3), 10 ppm (28 mg/m3), etc. {Contact info for Association of Occupational and Environmental Clinics (AOEC) & American College of Occupational and Environmental Medicine (ACOEM)}

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."

***** 1999 {Efficiency of various generating methods, Concentration & time. Etc.} "Higher strength solutions of sodium chlorite (e.g., 37 percent) also are more susceptible to crystallization or stratification at ambient temperatures as high as 25°C (78°F)." "In water treatment, chlorine dioxide solution concentrations rarely exceed 4 g/L for temperatures less than 40°C, and treatment levels generally range from 0.1 to 5.0 mg/L. " "Chlorine dioxide can be easily removed from dilute aqueous solution by turbulent aeration"

2006 core document. "Data on the mutagenicity of chlorine dioxide indicate that negative effects were reported in one study from a 400-fold drinking water concentrate of chlorine dioxide, whereas a 4000-fold concentrate was mutagenic only in the absence of metabolic activation. In another study, chlorine dioxide was positive for forward mutations under non-activated conditions. Chlorine dioxide was positive for structural chromosome aberrations under non-activated and activated conditions" "Agency has conservatively added the highest chronic dietary exposure to chlorite ion from consumption of food treated with inorganic chlorates to the total chronic dietary exposure from chlorine dioxide/sodium chlorite. This assumes that **all residues on food resulting from the use of inorganic chlorates are sodium chlorite**..l. [These numbers are] considered to be highly conservative because it is unlikely that significant chlorite residues will result from the use of inorganic chlorates on food crops."

********!!!!!!********** {Safe levels. 2000 is most recent date noted.} "...chlorine dioxide rapidly disappeared from the stored water (within 2-4 hours) and water chlorite concentrations concomitantly increased. Once absorbed, chlorine dioxide and chlorite are cleared from the blood at similar rates and are similarly distributed throughout the body .. Additionally, chloride is the major in vivo degradation product for chlorine dioxide, chlorite, and chlorate. The available data suggest that chlorine dioxide and chlorite have similar targets of toxicity and potencies. Therefore, the toxicity information for chlorite is relevant to deriving an RfD for chlorine dioxide." Integrated Risk Information System (IRIS)

****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.}

2007. Chlorine dioxide final volume 5

Sodium Chlorite combined with any GRAS acid for meat dip, seafood, raw agricultural commodities, etc

{Includes statements about chlorine dioxide's effects on human body.}

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−)"

2009. "Purpose: (1) Use a toxicity-based approach to prioritize and identify DBPs that show the greatest toxic response. (2) Comprehensively identify DBPs formed by different disinfectant regimes for the 'Four Lab Study'. (3) Determine the mechanisms of formation for potentially hazardous bromonitromethane DBPs."

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"

********* {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"

Other documents referenced as sources for Acute Exposure Guideline Levels (AEGLs). Chlorine Dioxide Acute Exposure Guideline Levels for Selected Airborne Chemicals, Volume 5, 2007.

**pg33 Results of exposure to aqueous CD can't be generalized to inhaled exposure

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