chlorine dioxide

H270: May cause or intensify fire; oxidizer [Danger Oxidizing gases]

H314: Causes severe skin burns and eye damage [Danger Skin corrosion/irritation]

H330: Fatal if inhaled [Danger Acute toxicity, inhalation]

H400: Very toxic to aquatic life [Warning Hazardous to the aquatic environment, acute hazard]

P220, P244, P260, P264, P271, P273, P280, P284, P301+P330+P331, P302+P361+P354, P304+P340, P305+P354+P338, P316, P320, P321, P363, P370+P376, P391, P403, P403+P233, P405, and P501 (click each P-code to see the statement)

H301: Toxic if swallowed [Danger Acute toxicity, oral]

P260, P264, P270, P273, P280, P301+P316, P301+P330+P331, P302+P361+P354, P304+P340, P305+P354+P338, P316, P321, P330, P363, P391, P405, and P501 (click each P-code to see the statement)

H270 (29.9%): May cause or intensify fire; oxidizer [Danger Oxidizing gases]

H280 (29.2%): Contains gas under pressure; may explode if heated [Warning Gases under pressure]

H301 (72.1%): Toxic if swallowed [Danger Acute toxicity, oral]

H314 (76.2%): Causes severe skin burns and eye damage [Danger Skin corrosion/irritation]

H318 (46.3%): Causes serious eye damage [Danger Serious eye damage/eye irritation]

H319 (24%): Causes serious eye irritation [Warning Serious eye damage/eye irritation]

H330 (29.9%): Fatal if inhaled [Danger Acute toxicity, inhalation]

H332 (15.9%): Harmful if inhaled [Warning Acute toxicity, inhalation]

H400 (76.2%): Very toxic to aquatic life [Warning Hazardous to the aquatic environment, acute hazard]

P220, P244, P260, P261, P264, P264+P265, P270, P271, P273, P280, P284, P301+P316, P301+P330+P331, P302+P361+P354, P304+P340, P305+P351+P338, P305+P354+P338, P316, P317, P320, P321, P330, P337+P317, P363, P370+P376, P391, P403, P403+P233, P405, P410+P403, and P501 (click each P-code to see the statement)

Aggregated GHS information provided per 542 reports by companies from 16 notifications to the ECHA C&L Inventory. Each notification may be associated with multiple companies.

Information may vary between notifications depending on impurities, additives, and other factors. The percentage value in parenthesis indicates the notified classification ratio from companies that provide hazard codes. Only hazard codes with percentage values above 10% are shown. For more detailed information, please visit ECHA C&L website.

P260, P264, P280, P301+P330+P331, P302+P361+P354, P304+P340, P305+P354+P338, P316, P321, P363, P405, and P501 (click each P-code to see the statement)

H320: Causes eye irritation [Warning Serious eye damage/eye irritation]

H336: May cause drowsiness or dizziness [Warning Specific target organ toxicity, single exposure; Narcotic effects]

H360: May damage fertility or the unborn child [Danger Reproductive toxicity]

H362: May cause harm to breast-fed children [Reproductive toxicity, effects on or via lactation]

H370: Causes damage to organs [Danger Specific target organ toxicity, single exposure]

H372: Causes damage to organs through prolonged or repeated exposure [Danger Specific target organ toxicity, repeated exposure]

H410: Very toxic to aquatic life with long lasting effects [Warning Hazardous to the aquatic environment, long-term hazard]

P203, P260, P261, P263, P264, P264+P265, P270, P271, P273, P280, P284, P304+P340, P305+P351+P338, P308+P316, P316, P318, P319, P320, P321, P337+P317, P391, P403+P233, P405, and P501 (click each P-code to see the statement)

P273, P391, and P501 (click each P-code to see the statement)

H315: Causes skin irritation [Warning Skin corrosion/irritation]

H319: Causes serious eye irritation [Warning Serious eye damage/eye irritation]

H341: Suspected of causing genetic defects [Warning Germ cell mutagenicity]

P203, P260, P264, P264+P265, P270, P271, P280, P284, P302+P352, P304+P340, P305+P351+P338, P308+P316, P316, P318, P319, P320, P321, P332+P317, P337+P317, P362+P364, P403+P233, P405, and P501 (click each P-code to see the statement)

Fresh air, rest. Half-upright position. Refer for medical attention.

First rinse with plenty of water for at least 15 minutes, then remove contaminated clothes and rinse again. Refer for medical attention .

First rinse with plenty of water for several minutes (remove contact lenses if easily possible), then refer for medical attention.

Excerpt from NIOSH Pocket Guide for Chlorine dioxide:

Eye: IRRIGATE IMMEDIATELY (LIQUID) - If this chemical in liquid form contacts the eyes, immediately wash (irrigate) the eyes with large amounts of water, occasionally lifting the lower and upper lids. Get medical attention immediately.

Skin: SOAP WASH IMMEDIATELY (LIQUID) - If this chemical in liquid form contacts the skin, immediately wash the contaminated skin with soap and water. If this chemical penetrates the clothing, immediately remove the clothing, wash the skin with soap and water, and get medical attention promptly.

Breathing: RESPIRATORY SUPPORT - If a person breathes large amounts of this chemical, move the exposed person to fresh air at once. If breathing has stopped, perform artificial respiration. Keep the affected person warm and at rest. Get medical attention as soon as possible.

Swallow: MEDICAL ATTENTION IMMEDIATELY (LIQUID) - If this chemical in liquid form has been swallowed, get medical attention immediately. (NIOSH, 2024)

(General first aid procedures)

Eye: Irrigate immediately (liquid)

Skin: Soap wash immediately (liquid)

Breathing: Respiratory support

Swallow: Medical attention immediately (liquid)

Excerpt from ERG Guide 143 [Oxidizers (Unstable)]:

SMALL FIRE: Use water. Do not use dry chemicals or foams. CO2 or Halon® may provide limited control.

LARGE FIRE: Flood fire area with water from a distance. Do not move cargo or vehicle if cargo has been exposed to heat. If it can be done safely, move undamaged containers away from the area around the fire. Do not get water inside containers: a violent reaction may occur.

FIRE INVOLVING TANKS, RAIL TANK CARS OR HIGHWAY TANKS: Cool containers with flooding quantities of water until well after fire is out. Dike runoff from fire control for later disposal. ALWAYS stay away from tanks in direct contact with flames. For massive fire, use unmanned master stream devices or monitor nozzles; if this is impossible, withdraw from area and let fire burn. (ERG, 2024)

In case of fire in the surroundings, use appropriate extinguishing media. In case of fire: keep drums, etc., cool by spraying with water. Combat fire from a sheltered position.

If material on fire or involved in fire: Use water in flooding quantities as fog. Cool all affected containers with flooding quantities of water. Extinguish fire using agent suitable for type of surrounding fire. (Material itself does not burn or burns with difficulty.) /Chlorine dioxide hydrate, frozen/

If fire becomes uncontrollable, consider evacuation of one-third mile radius. /Chlorine dioxide hydrate, frozen/

Firefighting gear (including SCBA) may not provide adequate protection. If exposure occurs, remove and isolate gear immediately and thoroughly decontaminate personnel. ... Use water only. Do not use dry chemical or carbon dioxide extinguishers. Use water with caution as chlorine dioxide reacts with water, forming hydrogen chloride gas. ... If material or contaminated runoff enters waterways, notify downstream users of potentially contaminated waters. Notify local health and fire officials and pollution control agencies. From a secure, explosion-proof location, use water spray to cool exposed containers. If cooling streams are ineffective (venting sound increases in volume and pitch, tank discolors, or shows any signs of deforming), withdraw immediately to a secure position. The only respirators recommended for firefighting are self-contained breathing apparatuses that have full face-pieces and are operated in a pressure-demand or other positive-pressure mode.

Small fire: Use water. Do not use dry chemicals or foams. CO2 or Halon may provide limited control. Large fire: Flood fire area with water from a distance. Do not move cargo or vehicle if cargo has been exposed to heat. Move containers from fire area if you can do it without risk. Do not get water inside containers: a violent reaction may occur. Fire involving tanks or car/trailer loads: Cool containers with flooding quantities of water until well after fire is out. Dike fire-control water for later disposal. ALWAYS stay away from tanks engulfed in fire. For massive fire, use unmanned hose holders or monitor nozzles; if this is impossible, withdraw from area and let fire burn.

A powerful oxidizer, this chemical will increase the intensity of a fire, and can cause fire upon contact with combustibles. ... Vapors are heavier than air and will collect in low areas. Containers may explode in fire. Storage containers and parts of containers may rocket great distances, in many directions.

Excerpt from ERG Guide 143 [Oxidizers (Unstable)]:

IMMEDIATE PRECAUTIONARY MEASURE: Isolate spill or leak area in all directions for at least 50 meters (150 feet) for liquids and at least 25 meters (75 feet) for solids.

SPILL: See ERG Table 1 - Initial Isolation and Protective Action Distances on the UN/NA 9191 datasheet.

FIRE: If tank, rail tank car or highway tank is involved in a fire, ISOLATE for 800 meters (1/2 mile) in all directions; also, consider initial evacuation for 800 meters (1/2 mile) in all directions. (ERG, 2024)

Evacuate danger area! Consult an expert! Personal protection: complete protective clothing including self-contained breathing apparatus. Ventilation. Remove gas with fine water spray.

Evacuate and restrict persons not wearing protective equipment from area of spill or leak until cleanup is complete. Remove all ignition sources. Ventilate area of leak or spill. If the gas is leaked, stop the flow of gas if it can be done safely. If the source of the leak is a cylinder and the leak cannot be stopped in place, remove the leaking cylinder to a safe place in the open air and repair the leak or alow the cylinder to empty. If the leak can be stopped in place, bubble chlorine dioxide through a solution made up of reducing agent sodium bisulfide and sodium bicarbonate with a trap in the line. For liquid spills, allow chlorine dioxide to evaporate with all available ventilation. Keep chlorine dioxide out of a confined space, such as a sewer, because of the possibility of an explosion, unless the sewer is designed to prevent the buildup of explosive concentrations. It may be necessary to contain and dispose of this chemical as a hazardous waste. If material or contaminated runoff enters waterways, notify downstream users of potentially contaminated waters.

Chlorine dioxide, hydrate, frozen, when spilled in water. Small spills (from a small package or a small leak from a large package): First: Isolate in all directions 100 ft/30 m. Then: Protect persons downwind: Day 0.1 mi/0.2 km, Night 0.1 mi/0.2 km. Large spills (from a large package or many small packages): First: Isolate in all directions 100 ft/30 m. Then: Protect persons downwind: Day 0.2 mi/0.3 km, Night 0.4 mi/0.6 km. /Chlorine dioxide, hydrate, frozen/

1) Remove all ignition sources. 2) Ventilate area of spill or leak. 3) If in gaseous form, stop flow of gas. If source of leak is a cylinder and leak cannot be stopped in place, remove leaking cylinder to safe place in open air, and repair leak or allow cylinder to empty. 4) If in liquid form, evacuate persons not wearing protective equipment. ... Allow ... to evaporate while providing all available ventilation.

SRP: Recycle any unused portion of the material for its approved use or return it to the manufacturer or supplier. Ultimate disposal of the chemical must consider: the material's impact on air quality; potential migration in air, soil or water; effects on animal, aquatic and plant life; and conformance with environmental and public health regulations. If it is possible or reasonable use an alternative chemical product with less inherent propensity for occupational harm/injury/toxicity or environmental contamination.

SRP: Wastewater from contaminant suppression, cleaning of protective clothing/equipment, or contaminated sites should be contained and evaluated for subject chemical or decomposition product concentrations. Concentrations shall be lower than applicable environmental discharge or disposal criteria. Alternatively, pretreatment and/or discharge to a permitted wastewater treatment facility is acceptable only after review by the governing authority and assurance that "pass through" violations will not occur. Due consideration shall be given to remediation worker exposure (inhalation, dermal and ingestion) as well as fate during treatment, transfer and disposal. If it is not practicable to manage the chemical in this fashion, it must be evaluated in accordance with EPA 40 CFR Part 261, specifically Subpart B, in order to determine the appropriate local, state and federal requirements for disposal.

Use large volume of concentrated solution of ferrous salt or bisulfite solution as reducing agent. Then neutralize and flush to sewer with abundant water.

Persons not wearing protective equipment and clothing should be restricted from areas of spills or leaks until cleanup has been completed.

If material not on fire and not involved in fire: Keep material out of water sources and sewers. /Chlorine dioxide hydrate, frozen/

Personnel protection: Avoid breathing vapors. ... Avoid bodily contact with the material. ... Do not handle broken packages unless wearing appropriate personal protective equipment. Wash away any material which may have contacted the body with copious amounts of water or soap and water. If contact with the material anticipated, wear appropriate chemical protective clothing. Approach fire with caution. /Chlorine dioxide hydrate, frozen/

SRP: The scientific literature for the use of contact lenses by industrial workers is inconsistent. The benefits or detrimental effects of wearing contact lenses depend not only upon the substance, but also on factors including the form of the substance, characteristics and duration of the exposure, the uses of other eye protection equipment, and the hygiene of the lenses. However, there may be individual substances whose irritating or corrosive properties are such that the wearing of contact lenses would be harmful to the eye. In those specific cases, contact lenses should not be worn. In any event, the usual eye protection equipment should be worn even when contact lenses are in place.

For more Preventive Measures (Complete) data for Chlorine dioxide (8 total), please visit the HSDB record page.

Excerpt from ERG Guide 143 [Oxidizers (Unstable)]:

Keep combustibles (wood, paper, oil, etc.) away from spilled material. Do not touch damaged containers or spilled material unless wearing appropriate protective clothing. Use water spray to reduce vapors or divert vapor cloud drift. Prevent entry into waterways, sewers, basements or confined areas.

SMALL SPILL: Flush area with large amounts of water.

LARGE SPILL: DO NOT CLEAN-UP OR DISPOSE OF, EXCEPT UNDER SUPERVISION OF A SPECIALIST. (ERG, 2024)

Fireproof if in building. Separated from combustible substances and reducing agents. Cool. Keep in the dark. Ventilation along the floor.

Store separately from all other flammable materials. Prior to working with chlorine dioxide you should be trained on its proper handling and storage. This chemical is a powerful oxidizer, and is shock-, light- and heat sensitive. It is violently explosive in air at concentrations over 10%. Keep frozen when not in use. Store in tightly closed containers in a cool, dark, well-ventilated area at temperatures well below 130 °C. Gas explosions may occur above 130 °C. Use only nonsparking tools and equipment, especially when opening and closing containers of this chemical. Sources of ignition, such as smoking and open flames, are prohibited where this chemical is used, handled, or stored in a manner that could create a potential fire or explosion hazard. Use explosion-proof electrical equipment and fittings in storage area.

TIH (Toxic Inhalation Hazard) - Term used to describe gases and volatile liquids that are toxic when inhaled. Some are TIH materials themselves, e.g., chlorine, and some release TIH gases when spilled in water, e.g., chlorosilanes. [ERG 2016].

0.1 [ppm]

AEGL 1: Notable discomfort, irritation, or certain asymptomatic non-sensory effects. However, the effects are not disabling and are transient and reversible upon cessation of exposure (Unit: ppm)

AEGL 2: Irreversible or other serious, long-lasting adverse health effects or an impaired ability to escape (Unit: ppm)

AEGL 3: Life-threatening health effects or death (Unit: ppm)

AEGLs Status: Final

0.15 [ppm]

1.1 [ppm]

2.4 [ppm]

0.1 ppm (0.3 mg/m³)

0.3 ppm (0.9 mg/m³)

TWA 0.1 ppm (0.3 mg/m3) ST 0.3 ppm (0.9 mg/m3)

TWA 0.1 ppm (0.3 mg/m3) See Appendix G

5 ppm (NIOSH, 2024)

5.0 [ppm]

Excerpts from Documentation for IDLHs: Human data: It has been reported that 5 ppm is definitely irritating and that 19 ppm caused the death of one worker inside a tank (time of exposure was not specified) [Elkins 1950].

See: 10049044

8 hr Time Weighted Avg (TWA): 0.1 ppm; 15 min Short Term Exposure Limit (STEL): 0.3 ppm.

2017 Notice of Intended Changes (NIC): These substances, with their corresponding values and notations, comprise those for which (1) a limit is proposed for the first time, (2) a change in the Adopted value is proposed, (3) retention as an NIC is proposed, or (4) withdrawal of the Documentation and adopted TLV is proposed. In each case, the proposals should be considered trial values during the period they are on the NIC. These proposals were ratified by the ACGIH Board of Directors and will remain on the NIC for approximately one year following this ratification. If the Committee neither finds nor receives any substantive data that changes its scientific opinion regarding an NIC TLV, the Committee may then approve its recommendation to the ACGIH Board of Directors for adoption. If the Committee finds or receives substantive data that change its scientific opinion regarding an NIC TLV, the Committee may change its recommendation to the ACGIH Board of Directors for the matter to be either retained on or withdrawn from the NIC. Substance: Chlorine dioxide; Time Weighted Avg (TWA): None; Short Term Exposure Limit (STEL): C 0.1 ppm; Notations: None; Molecular Weight: 67.50; TLV Basis: Respiratory tract irritation; lung edema.

(ceiling value): 0.1 ppm as STEL.

0.28 mg/m

ERPG-1: Not appropriate - one hour exposure limit: 1 = mild transient health effects or objectionable odor [AIHA]

ERPG-2: 0.5 ppm - one hour exposure limit: 2 = impaired ability to take protective action [AIHA]

ERPG-3: 3 ppm - one hour exposure limit: 3 = life threatening health effects [AIHA]

Emergency Response Planning Guidlines (ERPGs) for chlorine dioxide:[Table#1468]

USSR (1973): 0.03 ppm; Sweden and Germany: 0.1 ppm.

Australia TWA 0.1 ppm (0.3 mg/cu m); STEL 0.3 ppm (0.9 mg/cu m)

Austria TWA 0.1 ppm (0.3 mg/cu m)

Belgium TWA 0.1 ppm (0.28 mg/cu m); STEL 0.3 ppm (0.32 mg/cu m)

For more Other Standards Regulations and Guidelines (Complete) data for Chlorine dioxide (19 total), please visit the HSDB record page.

A harmful concentration of this gas in the air will be reached very quickly on loss of containment.

The substance is severely irritating to the eyes, skin and respiratory tract. Inhalation of this gas may cause lung oedema. Exposure far above the OEL could cause death. The effects may be delayed. Medical observation is indicated.

The substance may have effects on the lungs. This may result in chronic bronchitis.

Residues of the following chemical substances are exempted from the requirement of a tolerance when used in accordance with good manufacturing practice as ingredients in an antimicrobial pesticide formulation, provided that the substance is applied on a semi-permanent or permanent food-contact surface (other than being applied on food packaging) with adequate draining before contact with food. ... (b) The following chemical substances when used as ingredients in an antimicrobial pesticide formulation may be applied to: Dairy processing equipment, and food-processing equipment and utensils. ... Pesticide Chemical: Oxychloro species (including chlorine dioxide) generated by acidification of an aqueous solution of sodium chlorite. Limit: When ready for use, the end-use concentration is not to exceed 200 ppm of chlorine dioxide as determined by the method titled, Iodometric Method for the Determination of Available Chlorine Dioxide (50-250 ppm available chlorine dioxide)

Residues of the following chemical substances are exempted from the requirement of a tolerance when used in accordance with good manufacturing practice as ingredients in an antimicrobial pesticide formulation, provided that the substance is applied on a semi-permanent or permanent food-contact surface (other than being applied on food packaging) with adequate draining before contact with food. ... (c) The following chemical substances when used as ingredients in an antimicrobial pesticide formulation may be applied to: Food-processing equipment and utensils. ... Pesticide Chemical: Oxychloro species (including chlorine dioxide) generated by acidification of an aqueous solution of sodium chlorite. Limit: When ready for use, the end-use concentration is not to exceed 200 ppm of chlorine dioxide as determined by the method titled, "Iodometric Method for the Determination of Available Chlorine Dioxide (50-250 ppm available chlorine dioxide)"

Residues of the following chemical substances are exempted from the requirement of a tolerance when used in accordance with good manufacturing practice as ingredients in an antimicrobial pesticide formulation, provided that the substance is applied on a semi-permanent or permanent food-contact surface (other than being applied on food packaging) with adequate draining before contact with food. ... (c) The following chemical substances when used as ingredients in an antimicrobial pesticide formulation may be applied to: Food-processing equipment and utensils. ... Pesticide Chemical: Oxychloro species (predominantly chlorite, chlorate and chlorine dioxide in an equilibrium mixture) generated either (i) by directly metering a concentrated chlorine dioxide solution prepared just prior to use, into potable water, or (ii) by acidification of an aqueous alkaline solution of oxychloro species (predominately chlorite and chlorate) followed by dilution with potable water. Limit: When ready for use, the end-use concentration is not to exceed 200 ppm of chlorine dioxide as determined by the method titled, "Iodometric Method for the Determination of Available Chlorine Dioxide (50-250 ppm available chlorine dioxide)"

Excerpt from NIOSH Pocket Guide for Chlorine dioxide:

Skin: PREVENT SKIN CONTACT (LIQUID) - If this chemical is in liquid form, wear appropriate personal protective clothing to prevent skin contact.

Eyes: PREVENT EYE CONTACT (LIQUID) - If this chemical is in liquid form, wear appropriate eye protection to prevent eye contact.

Wash skin: WHEN CONTAMINATED (LIQUID) - If this chemical is in liquid form, the worker should immediately wash the skin when it becomes contaminated.

Chlorine dioxide hydrate, frozen is an orange colored solid, appearing as a block of ice, with a faint odor of chlorine. It may only be shipped in the frozen state and then only by private or contract motor carrier. The melting point of the hydrate is around 30 °F. If it should thaw and further warm up, chlorine dioxide gas is given off. The gas is toxic by inhalation. The gas and liquid are violently decomposed by organic materials. The gas will decompose explosively at temperatures below the boiling point of water. It is used to bleach wood pulp, fats and oils; in processing flour, and for water purification. Chlorine dioxide is a yellow to reddish gas or a red-brown liquid below 52 deg. F. with an unpleasant odor similar to chlorine.

Liquid; Gas Vapor

Yellow to red gas or a red-brown liquid (below 52 degrees F) with an unpleasant odor similar to chlorine and nitric acid; [NIOSH] Vapor density = 2.3 (heavier than air); [ACGIH]

RED-YELLOW GAS WITH PUNGENT ODOUR.

Yellow to red gas or a red-brown liquid (below 52 °F) with an unpleasant odor similar to chlorine and nitric acid.

Yellowish-brown gas

Yellow to reddish-yellow gas at room temperature

Solid chlorine dioxide is a yellowish-red crystalline mass; liquid is reddish-brown

Yellow to red gas or a red-brown liquid (below 52 degrees F) ...

For more Color/Form (Complete) data for Chlorine dioxide (6 total), please visit the HSDB record page.

... Unpleasant odor similar to chlorine and nitric acid.

52 °F at 760 mmHg (NIOSH, 2024)

11 °C @760 [mm Hg]

-74 °F (NIOSH, 2024)

NA (Gas) ? (Liquid)

0.3 % at 77 °F (NIOSH, 2024)

In water, 3.01 g/L at 25 °C and 34.5 mm Hg

2000 cc (gas) in 100 cc cold water

In water, 1.823X10-2 at 298.15 K

Soluble in water

Soluble in alkaline and sulfuric acid solutions

Solubility in water, g/100ml at 20 °C: 0.8

(77 °F): 0.3%

1.6 (Liquid at 32 °F) (NIOSH, 2024) - Denser than water; will sink

1.77 g/cu cm

Density: 1.642 at 0 °C (liq)

Relative density (water = 1): 1.6 (liquid, 0 °C)

1.6 (liquid at 32 °F)

3.09 @ 11°C

1.6 (Liquid at 32 °F)

2.33(relative gas density)

2.33 (NIOSH, 2024) - Heavier than air; will sink (Relative to Air)

2.3 (Air = 1)

Relative vapor density (air = 1): 2.3

greater than 1 atm (NIOSH, 2024)

101 kPa at 20 °C /758 mm Hg at 20 °C/

Vapor pressure, kPa at 20 °C: 101

Unstable in light; stable in dark if pure, but chlorides catalyze its decomposition even in the dark.

Solutions in pure water can be maintained for months in closed containers.

Concentrated chlorine dioxide vapor is potentially explosive, and attempts to compress and store this gas, either alone or in combination with other gases, have been commercially unsuccessful. Because of this, chlorine dioxide, like ozone, must be manufactured at the point of use. Chlorine dioxide in water does not hydrolyze to any appreciable extent. Neutral or acidic dilute aqueous solutions are quite stable if kept cool, well sealed and protected from sunlight.

Decomposes in water, products likely to include gaseous Cl2 (Lewis 2000).

Reacts with water to produce toxic and corrosive fumes of chlorine. Based on a scenario where the chemical is spilled into an excess of water (at least 5 fold excess of water), half of the maximum theoretical yield of Chlorine gas will be created in 0.14 minutes. Experimental details are in the following: "Development of the Table of Initial Isolation and Protective Distances for the 2008 Emergency Response Guidebook", ANL/DIS-09-2, D.F. Brown, H.M. Hartmann, W.A. Freeman, and W.D. Haney, Argonne National Laboratory, Argonne, Illinois, June 2009.

Oxidizing Agents, Strong

Halogenating Agents

Explosive

Strong Oxidizing Agent

Water-Reactive

CHLORINE DIOXIDE is a powerful oxidizer of low stability. Explodes violently on the slightest provocation as gas or liquid even below -100 °C by impact [Sidgwick, 1950, 1203; Stedman, R. F., Chem Eng. News, 1951, 29, p. 5030]. Mixtures with carbon monoxide, methane, ethane, propane, ethylene or butadiene always explode spontaneously. Concentrations of greater than 10% in air are explosive. Severe explosion hazard when heated to 100 °C. Sensitive to shock and sunlight. Explodes on contact with mercury, potassium hydroxide, phosphorus, phosphorus pentachloride, sulfur, difluoramine, trifluoramine, sugar. Very sensitive to the presence of any easily oxidized material. These may, even in minute quantities, trigger a decomposition. Materials such as rubber, hydrocarbons, carbon, iron, rust, reactive metals, and organics such as sawdust have all caused problems. [Inorganic Chemistry Handbook]. Emits highly toxic fumes of chlorine gas upon decomposition. Can react violently with fluorine, reducing reagents or finally dispersed organic matter [Bretherick, 5th ed., 1995, p. 1292].

Explodes on mixing with carbon monoxide, hydrocarbons (e.g., butadiene, ethane, ethylene, methane, propane), fluoramines (e.g. difluoramine, trifluoramine). Mixtures with hydrogen explode with sparking or contact with platinum. Explodes on contact with mercury, potassium hydroxide, phosphorous pentachloride + chlorine. Ignites or explodes on contact with non-metals (e.g., phosphorous, sulfur, sugar). Reacts violently with /fluorine/, NHF2. Reacts with water or steam to produce toxic and corrosive fumes of /hydrochloric acid/.

Reacts violently with organic materials.

The gas phase reaction of chlorine dioxide and difluoroamine is explosive.

Organic matter in contact with chlorine dioxide can be exploded by shock or sparks.

For more Hazardous Reactivities and Incompatibilities (Complete) data for Chlorine dioxide (19 total), please visit the HSDB record page.

Organic materials, heat, phosphorus, potassium hydroxide, sulfur, mercury, carbon monoxide [Note: Unstable in light. A powerful oxidizer.]

CDC-ATSDR Toxicological Profile

IDENTIFICATION AND USE: Chlorine dioxide is a yellowish-brown gas with unpleasant odor similar to chlorine and nitric acid. Its uses include bleaching cellulose, paper-pulp, flour, leather, fats and oils, textiles, and beeswax. It is also used for purification of water, taste and odor control of water, cleaning and detanning leather, in the manufacture of chloride salts, and as an oxidizing agent, bactericide, antiseptic and deodorizer. Chlorine dioxide was found to be highly effective against various microorganisms tested at very low concentrations in a minimum contact time of 30 to 60 seconds. HUMAN STUDIES: Potential symptoms of overexposure are irritation of eyes, nose, and throat, as well as coughing, wheezing, bronchitis, and pulmonary edema. Workers industrially exposed to low concentrations of the gas in air have been noted occasionally to suffer from irritation of the eyes and to see haloes about lights, but these effects have been minor compared to respiratory irritation. Bronchoscopy and biopsy revealed slight chronic bronchitis in 7 of 12 workers. Only two workers who had been exposed just prior to examination showed physical signs of respiratory effects. Workers acutely exposed to chlorine dioxide developed both reactive airways dysfunction syndrome (RADS), a form of occupational asthma, and an upper airways reactive disorder that was called reactive upper airways disfunction syndrome (RUDS). A positive association was found between exposure of the mother to chlorine dioxide-treated water during pregnancy and prematurity of the newborn. Children born of mothers who drank disinfected water treated with either chlorine dioxide or hypochlorite were noted to have an increased incidence of small cranial circumference, small body length, and neonatal jaundice. Chlorine dioxide was found to be weakly genotoxic in human leukocytes. ANIMAL STUDIES: Chlorine dioxide is very toxic by inhalation in rats. Clinical signs of toxicity included respiratory distress. Macroscopically, pulmonary edema and emphysema were seen in all groups of chlorine dioxide-exposed animals, with the incidence increasing in a dose-related manner. Chlorine dioxide is toxic when administered in solution by the oral route to rats. Two males and two females receiving 80 mg chlorine dioxide/kg body weight died, and a further two males at 40 mg/kg body weight also died within 48 hr of administration. There were no deaths at 20 mg/kg body weight. A developmental study in rats did not demonstrate any impairment of reproductive function, and there were no signs of developmental effects among rats receiving up to 10 mg aqueous chlorine dioxide/kg body weight per day. A negative result was obtained for micronucleus formation, and there were no increases in the number of structural or numerical chromosome aberrations in mice treated with chlorine dioxide. However, chlorine dioxide increased water genotoxicity in assays with E. coli and with S. cerevisiae. In Chinese hamster ovary cells at 2.5-15 ug/mL, there was a marked dose-related, statistically significant increase in the number of metaphases with chromosome aberrations. In the presence of metabolic activation, cell toxicity and an absence of mitotic cells were observed at 75 ug/mL. An increase in the number of metaphases with chromosome aberrations was noted at 50 ug/mL. ECOTOXICITY STUDIES: Developmental abnormalities in the sea urchin were evident at exposure to the chlorine dioxide concentration 250 mg/L. Compared with the control, pre-hatch malformations were 6% higher; retarded development, 2%; post-hatch malformations, 20%; skeletal malformations, 21%; and gut malformations, 11%. Survival of larval kelp bass was not significantly affected by chlorine dioxide. In Fathead minnows (Pimephales promelas) chlorine dioxide exposure produced dose-dependent gill pathology including epithelial lifting, hypertrophy, hyperplasia, lamellar fusion, and necrosis. Complete recovery, even in fish with severe hypertrophy and lamellar fusion, was achieved within 4 days. Chlorine dioxide concentrations ranging from 0.1 to 0.5 mg/L induced micronuclei in Vicia faba at acid pH, while 1-2 mg/L chlorine dioxide gave positive responses at neutral pH. Chlorine dioxide produced positive responses in the Tradescantia micronucleus test.

Chlorine dioxide

Cardiovascular

Developmental

Respiratory

3 x 10 ^-2 mg/kg-day

2 x 10 ^-4 mg/m^3

CLASSIFICATION: D; not classifiable as to human carcinogenicity. BASIS FOR CLASSIFICATION: No satisfactory human or animal studies assessing the chronic carcinogenic potential of chlorine dioxide have been located. HUMAN CARCINOGENICITY DATA: None. ANIMAL CARCINOGENICITY DATA: None.

The substance can be absorbed into the body by inhalation.

inhalation, ingestion (liquid), skin and/or eye contact

Cough. Headache. Laboured breathing. Nausea. Shortness of breath. Sore throat. Symptoms may be delayed.

Redness. Pain.

irritation eyes, nose, throat; cough, wheezing, bronchitis, pulmonary edema; chronic bronchitis

Developmental (effects while organs are developing), Gastrointestinal (Stomach and Intestines, part of the digestive system), Respiratory (From the Nose to the Lungs)

Eyes, respiratory system

Dermatotoxin - Skin burns.

Toxic Pneumonitis - Inflammation of the lungs induced by inhalation of metal fumes or toxic gases and vapors.

... One may calculate the 24 hr SNARL /suggested no adverse response level/ as ... 1.2 mg/L.

7-Day exposure: ... One may calculate the SNARL /suggested no adverse response level/ as ... 0.125 mg/L.

IRIS Current

ATSDR Final

LCLo (rat) = 260 ppm/2H

LD50 Rat oral 292 mg/kg

LC50 Rat inhalation 32 ppm (90 mg/cu m) 4 hr

LD50 Rat oral 94 mg/kg body weight

Immediate first aid: Ensure that adequate decontamination has been carried out. If patient is not breathing, start artificial respiration, preferably with a demand-valve resuscitator, bag-valve-mask device, or pocket mask, as trained. Perform CPR if necessary. Immediately flush contaminated eyes with gently flowing water. Do not induce vomiting. If vomiting occurs, lean patient forward or place on left side (head-down position, if possible) to maintain an open airway and prevent aspiration. Keep patient quiet and maintain normal body temperature. Obtain medical attention. /Chlorine and related compounds/

Basic treatment: Establish a patent airway (oropharyngeal or nasopharyngeal airway, if needed). Suction if necessary. Watch for signs of respiratory insufficiency and assist ventilations if necessary. Administer oxygen by nonrebreather mask at 10 to 15 L/min. Monitor for pulmonary edema and treat if necessary ... . Monitor for shock and treat if necessary ... . For eye contamination, flush eyes immediately with water. Irrigate each eye continuously with 0.9% saline (NS) during transport ... . Do not use emetics. For ingestion, rinse mouth and administer 5 mL/kg up to 200 mL of water for dilution if the patient can swallow, has a strong gag reflex, and does not drool ... . Cover skin burns with dry sterile dressings after decontamination ... . /Chlorine and related compounds/

Advanced treatment: Consider orotracheal or nasotracheal intubation for airway control in the patient who is unconscious, has severe pulmonary edema, or is in severe respiratory distress. Positive-pressure ventilation techniques with a bag-valve-mask device may be beneficial. Consider drug therapy for pulmonary edema ... . Monitor cardiac rhythm and treat arrhythmias if necessary ... . Start IV administration of D5W /SRP: "To keep open", minimal flow rate/. Use 0.9% saline (NS) or lactated Ringer's (LR) if signs of hypovolemia are present. For hypotension with signs of hypovolemia, administer fluid cautiously. Consider vasopressors if patient is hypotensive with a normal fluid volume. Watch for signs of fluid overload ... . Use proparacaine hydrochloride to assist eye irrigation ... . /Chlorine and related compounds/

Immediate first aid: Ensure that adequate decontamination has been carried out as needed. If patient is not breathing, start artificial respiration, preferably with a demand-valve resuscitator, bag-valve-mask device, or pocket mask, as trained. Perform CPR if necessary. Immediately flush contaminated eyes with gently flowing water. Do not induce vomiting. If vomiting occurs, lean patient forward or place on left side (head-down position, if possible) to maintain an open airway and prevent aspiration. Keep patient quiet and maintain normal body temperature. Obtain medical attention. /Choking Agents (Pulmonary/Lung-Damaging Agents)/

For more Antidote and Emergency Treatment (Complete) data for Chlorine dioxide (7 total), please visit the HSDB record page.

/HUMAN EXPOSURE STUDIES/ An assessment of the safety of chronically administered chlorine water disinfectants in man was conducted in 3 phases. Phase I, a rising dose tolerance investigation, examined the effects of single dose incr concn admin of disinfectants to normal healthy adult male volunteers. Phase II considered the impact on normal subjects of 12 wk daily ingestion of the disinfectants at a concn of 5 mg/L. In phase III, chlorite, at a concn of 5 mg/L, was administered daily to glucose 6-phosphate dehydrogenase (G-6-PD)-deficient subjects. The study affirmed the relative safety and tolerance of normal healthy adult males and normal healthy adult male G-6-PD-deficient individuals to daily 12 wk ingestion of 500 mL of chlorine disinfectants at a concentration of 5 mg/L. /Disinfection byproducts/

/HUMAN EXPOSURE STUDIES/ In a series of extensive human volunteer studies on water disinfectants, groups of 10 males received aqueous chlorine dioxide in drinking-water by a range of different protocols (a sequence of rising concentrations of up to around 0.34 mg/kg body weight over a 16-day period, approximately 0.035 mg/kg body weight on every third day for 12 weeks, or approximately 3.6 x 10-5 mg aqueous chlorine dioxide/kg body weight per day daily for 12 weeks). Observations included physical examination (blood pressure, respiration rate, pulse, oral temperature, and electrocardiography), extensive blood biochemistry, hematology, and urinalysis, and the subjective recording of taste. There were no significant adverse effects recorded for any of the parameters measured.

/SIGNS AND SYMPTOMS/ Potential symptoms of overexposure are irritation of eyes, nose, and throat; coughing, wheezing, bronchitis, pulmonary edema; chronic bronchitis.

/SIGNS AND SYMPTOMS/ ... A 5 ppm concentration of chlorine dioxide was definitely irritating and ... 19 ppm of the gas inside a bleach tank was more than sufficient to cause the death of one worker (time of exposure not specified) ... . Based on these findings, /investigators/ suggested in 1950 a maximal acceptable concentration of 1 ppm.

For more Human Toxicity Excerpts (Complete) data for Chlorine dioxide (26 total), please visit the HSDB record page.

/LABORATORY ANIMALS: Acute Exposure/ Chlorine dioxide is very toxic by inhalation in rats. Groups of five male and five female rats were exposed, nose only, to 0, 16, 25, 38, or 46 ppm (0, 45, 70, 106, or 129 mg/cu m) chlorine dioxide gas for 4 hr. There were no mortalities at 16 ppm (45 mg/cu m) or in controls. However, there were 3/5, 4/5, and 5/5 deaths among males and 5/5, 2/5, and 4/5 deaths among females at 25, 38, and 46 ppm (70, 106, and 129 mg/cu m), respectively. Clinical signs of toxicity included respiratory distress. Macroscopically, pulmonary edema and emphysema were seen in all groups of chlorine dioxide-exposed animals, with the incidence increasing in a dose-related manner.

/LABORATORY ANIMALS: Acute Exposure/ Chlorine dioxide is toxic when administered in solution by the oral route to rats. Groups of five male and five female rats received a single oral gavage dose of 10, 20, or 40 mL aqueous 0.2% w/v chlorine dioxide/kg body weight (not 2%, as stated in the test reports). However, as correctly stated, the administered doses corresponded to 20, 40, and 80 mg chlorine dioxide/kg body weight. Two males and two females receiving 80 mg chlorine dioxide/kg body weight died, and a further two males at 40 mg/kg body weight also died within 48 hr of administration. There were no deaths at 20 mg/kg body weight. General clinical signs of toxicity were observed among all treated groups of animals; in addition, there were occasional observations of red nasal discharge. Macroscopically, at 40 and 80 mg/kg body weight only, animals showed signs of corrosive activity in the stomach and gastrointestinal tract. There were no other treatment-related macroscopic abnormalities.

/LABORATORY ANIMALS: Acute Exposure/ Groups of five male Sprague-Dawley rats received approximately 0, 0.12, 0.24, or 0.48 mg aqueous chlorine dioxide/kg body weight by oral gavage. Samples of blood were taken at 15, 30, 60, and 120 minutes post-administration for analysis of glutathione and methemoglobin levels and osmotic fragility; methemoglobin formation was not observed, and the other parameters measured were only slightly affected, with no clear dose-response relationship.

/LABORATORY ANIMALS: Acute Exposure/ Female SENCAR mice were treated with aqueous solutions of hypochlorous acid, sodium hypochlorite, chlorine dioxide, and monochloramine by whole body exposure (except head) for a 10 min period for 4 days in the first experiment and for 1 day (except NH2Cl) in the second experiment. Animals were sacrificed the day following the last treatment (experiment 1) or on day 1, 2, 3, 4, 5, 8, 10, and 12 following treatment (experiment 2), and skin thickness was measured by light microscopy at x400 by use of an eyepiece micrometer. Concentrations of disinfectants were 1, 10, 100, 300, and 1000 mg/L, for experiment 1 and 1000 mg/L for experiment 2. Thickness of the interfollicular epidermis for control animals was 15.4 +/- 1.5 micron. After 4 days of treatment at 1000 mg/L, hypochlorous acid and chlorine dioxide increased thickness to 39 +/- 7.0 and 40.2 +/- 11.8, and sodium hypochlorite increased thickness to 25.2 +/- 6.1 micron. Only hypochlorous acid and chlorine dioxide were tested at 300 mg/L, yielding an interfollicular epidermis thickness of 30.0 +/- 13.1 and 16.8 +/- 0.8 micron, respectively. The response to HOCl was found to be dose related; the minimally effective dose was 100 mg/L. In earlier, preliminary tests to determine optimum treatment schedule, the response to hypochlorous acid appeared to be maximal after 4 days of treatment and tended to decrease with further treatment. The time-course study following a single treatment of 1000 mg/L hypochlorous acid, however, showed a progression of interfollicular epidermis thickening of from 18.3 +/- 1.4 at 1 day to 30.8 +/- 8.0 at 8 days, decreasing to 19.1 +/- 6.2 micron at 12 days.

LC50; Species: Pimephales promelas (Fathead minnow) juvenile; Conditions: flow through; Concentration: 0.02 mg/L for 96 hr

LC50; Species: Pimephales promelas (Fathead minnow) adult- 1 yr old; Conditions: flow through; Concentration: 0.17 mg/L for 96 hr

LC50; Species: Lepomis macrochirus (Bluegill) young of the year; Conditions: flow through; Concentration: 0.15 mg/L for 96 hr

LC50; Species: Carcinus maenas (Green or Europeon shore crab); Conditions: renewal; Concentration: 500 mg/L for 48 hr /technical product/

For more Ecotoxicity Values (Complete) data for Chlorine dioxide (16 total), please visit the HSDB record page.

/AQUATIC SPECIES/ Antifouling biocides are commonly used in coastal electric power stations to prevent biofouling in their condenser cooling systems. However, the environmental impact of the chemical biocides is less understood than the thermal stress effects caused by the condenser effluents. In this study, Chaetoceros lorenzianus, a representative marine diatom, was used to analyze the toxicity of two antifouling biocides, chlorine and chlorine dioxide. The diatom cells were subjected to a range of concentrations of the biocides (from 0.05 to 2 mg/L, as total residual oxidants, TRO) for contact time of 30min. They were analyzed for viability, genotoxicity, chlorophyll a and cell density endpoints. The cells were affected at all concentrations of the biocides (0.05-2 mg/L), showing dose-dependent decrease in viability and increase in DNA damage. The treated cells were later incubated in filtered seawater devoid of biocide to check for recovery. The cells were able to recover in terms of overall viability and DNA damage, when they had been initially treated with low concentrations of the biocides (0.5 mg/L of Cl2 or 0.2 mg/L of ClO2). Chlorophyll a analysis showed irreparable damage at all concentrations, while cell density showed increasing trend of reduction, if treated above 0.5 mg/L of Cl2 and 0.2 mg/L of ClO2. The data indicated that in C. lorenzianus, cumulative toxic effects and recovery potential of ClO2 up to 0.2 mg/L were comparable with those of Cl2, up to 0.5 mg/L concentration in terms of the studied endpoints. The results indicate that at the biocide levels currently being used at power stations, recovery of the organism is feasible upon return to ambient environment. Similar studies should be carried out on other planktonic and benthic organisms, which will be helpful in the formulation of future guidelines for discharge of upcoming antifouling biocides such as chlorine dioxide.

/AQUATIC SPECIES/ Environmental effect evaluation of disinfection of combined sewer overflow events with alternative chemical disinfectants requires that the environmental toxicity of the disinfectants and the main by-products of their use are known. Many disinfectants degrade quickly in water which should be included in the evaluation of both their toxicity as determined in standardized tests and their possible negative effect in the water environment. Here we evaluated according to the standardized ISO 8692 test the toxicity towards the green microalgae, Pseudokirchneriella subcapitata, of three disinfectants: performic acid (PFA), peracetic acid (PAA) and chlorine dioxide (ClO2) as well as two by-products of their use: hydrogen peroxide (H2O2) and chlorite. All of the five chemicals investigated showed clear toxicity to the algae with well-defined dose response curves. The EC50 values ranged from 0.16 to 2.9 mg/L based on nominal concentrations leading to the labeling of the chemicals as either toxic or very toxic. The five investigated chemicals decreased in toxicity in the order chlorine dioxide, performic acid, peracetic acid, chlorite and hydrogen peroxide. The stability of the chemicals increased in the same order as the toxicity decrease. This indicates that even though ClO2 has the highest environmental hazard potential, it may still be suitable as an alternative disinfectant due to its rapid degradation in water.

/AQUATIC SPECIES/ Whether the implementation of additional treatments for the removal of estrogens from wastewater treatment works (WwTWs) effluents will eliminate their feminizing effects in exposed wildlife has yet to be established, and this information is crucial for future decisions on investment into WwTWs. Here, granular activated carbon (GAC), ozone (O(3)), and chlorine dioxide (ClO(2)) were investigated for their effectiveness in reducing steroidal estrogen levels in a WwTW effluent and assessments made on the associated estrogenic and reproductive responses in fathead minnows (Pimephales promelas) exposed for 21 days. All treatments reduced the estrogenicity of the standard-treated (STD) effluent, but with different efficacies; ranging between 70-100% for total estrogenicity and 53-100% for individual steroid estrogens. In fish exposed to the GAC- and ClO(2)- (but not O(3)-) treated effluents, there was no induction of plasma vitellogenin (VTG) or reduction in the weight of the fatpad, a secondary sex character in males, as occurred for fish exposed to STD effluent. This finding suggests likely benefits of employing these treatment processes for the reproductive health in wild fish populations living in rivers receiving WwTW discharges. Exposure of pair-breeding minnows to the GAC-treated effluent, however, resulted in a similar inhibition of egg production to that occurring for exposure to the STD effluent (34-40%). These data, together with a lack of effect on egg production of the estrogen, ethinylestradiol (10 ng/L), alone, suggest that chemical/physical properties of the effluents rather than their estrogenicity were responsible for the reproductive effect and that these factor(s) were not remediated for through GAC treatment. Collectively, our findings illustrate the importance of assessing integrative biological responses, rather than biomarkers alone, in the assessment and improvement of WwTW technologies for the protection of wild fish populations.

/AQUATIC SPECIES/ Epidemiological evidence suggests a link between consumption of chlorinated drinking water and various cancers. Chlorination of water rich in organic chemicals produces carcinogenic organochlorine by-products (OBPs) such as trihalomethanes and haloacetic acids. Since the discovery of the first OBP in the 1970s, there have been several investigations designed to determine the biological effects of single chemicals or small artificial OBP combinations. However, there is still insufficient information regarding the general biological response to these compounds, and further studies are still needed to evaluate their potential genotoxic effects. In the current study, we evaluated the effect of three drinking water disinfectants on the activity of cytochrome P450 (CYP)-linked metabolizing enzymes and on the generation of oxidative stress in the livers of male and female Cyprinus carpio fish (carp). The fish were exposed in situ for up 20 days to surface water obtained from the Trasmene lake in Italy. The water was treated with 1-2 mg/L of either sodium hypochlorite (NaClO) or chlorine dioxide (ClO2) as traditional disinfectants or with a relatively new disinfectant product, peracetic acid (PAA). Micronucleus (MN) frequencies in circulating erythrocytes from the fish were also analyzed as a biomarker of genotoxic effect. In the CYP-linked enzyme assays, a significant induction (up to a 57-fold increase in the deethylation of ethoxyresorufin with PAA treatment) and a notable inactivation (up to almost a 90% loss in hydroxylation of p-nitrophenol with all disinfectants, and of testosterone 2beta-hydroxylation with NaClO) was observed in subcellular liver preparations from exposed fish. Using the electron paramagnetic resonance (EPR) spectroscopy radical-probe technique, we also observed that CYP-modulation was associated with the production of reactive oxygen species (ROS). In addition, we found a significant increase in MN frequency in circulating erythrocytes after 10 days of exposure of fish to water treated with ClO2, while a non-significant six-fold increase in MN frequency was observed with NaClO, but not with PAA. Our data suggest that the use of ClO2 and NaClO to disinfect drinking water could generate harmful OBP mixtures that are able to perturb CYP-mediated reactions, generate oxidative stress and induce genetic damage. These data may provide a mechanistic explanation for epidemiological studies linking consumption of chlorinated drinking water to increased risk of urinary, gastrointestinal and bladder cancers.

For more Ecotoxicity Excerpts (Complete) data for Chlorine dioxide (14 total), please visit the HSDB record page.

2.30e+03

3.40e+04

2.10e-01

8.80e-01

4.20e-01

8.0E+02(G)

3.00e-02

2.00e-04

Volatile

7.00e+03

1.00e+05

6.30e-01

2.60e+00

1.30e+00

8.0E+02 (G)

This substance may be hazardous to the environment. Special attention should be given to aquatic organisms.

Chlorine dioxide's production and use as an oxidizing bleaching agent in the pulp and paper industry(1) will result in its release to the environment through various waste streams(SRC). Its use as a disinfectant in industrial and municipal water treatment and oxidizer in oil field and pollution abatement processes(1) will result in its direct release to the environment(SRC).

Hydrogen peroxide (H2O2), chlorite, chlorate, Cl2O3, oxygen (O2), and chlorine have all been reported as intermediates or products /of chlorine dioxide breakdown/. Presumably chlorine dioxide will not persist in open basins or reservoirs, although it can remain for days in clean distribution systems.

It is generally accepted that the predominant reaction product of chlorine dioxide in water treatment is chlorite and that chlorate and other ions are produced in minor amounts ... an approximately 50% conversion of chlorine dioxide to chlorite was reported ... /in/ water containing natural humic acids.

Chlorine dioxide does not cause formation of trihalomethanes, does not react with ammonia, and does not cause formation of chloramines. It can ... disproportionate to chlorate and chlorite ... by raising pH to 11 or 12 ... this is not believed to be an important reaction in water undergoing treatment.

/Products formed during oxidative treatment of water/: both oxygenated and chlorinated products may be formed, the latter being found most prominently in connection with reactions of phenolic substances. Other products that might affect health are quinones and 1,2-epoxy compounds.

Since chlorite is formed at a rate of 50% of the chlorine dioxide demand, serious consideration must be given to limiting chlorite formation before chlorine dioxide is adopted as disinfectant to replace chlorine.

Proposed limits of use of chlorine dioxide were based primarily upon assessment of hazards of residual chlorite. Concerned with possible in-vivo methemoglobin production by chlorite ... recommended that no chlorite reach the distribution point

According to the 2016 TSCA Inventory Update Reporting data, 72 reporting facilities estimate the number of persons reasonably likely to be exposed during the manufacturing, processing, or use of chlorine dioxide in the United States may be as low as 25 workers and as high as 1,000 workers per plant; the data may be greatly underestimated due to confidential business information (CBI) or unknown values(1).

SRP: Recycle any unused portion of the material for its approved use or return it to the manufacturer or supplier. Ultimate disposal of the chemical must consider: the material's impact on air quality; potential migration in air, soil or water; effects on animal, aquatic and plant life; and conformance with environmental and public health regulations. If it is possible or reasonable use an alternative chemical product with less inherent propensity for occupational harm/injury/toxicity or environmental contamination.

SRP: Wastewater from contaminant suppression, cleaning of protective clothing/equipment, or contaminated sites should be contained and evaluated for subject chemical or decomposition product concentrations. Concentrations shall be lower than applicable environmental discharge or disposal criteria. Alternatively, pretreatment and/or discharge to a permitted wastewater treatment facility is acceptable only after review by the governing authority and assurance that "pass through" violations will not occur. Due consideration shall be given to remediation worker exposure (inhalation, dermal and ingestion) as well as fate during treatment, transfer and disposal. If it is not practicable to manage the chemical in this fashion, it must be evaluated in accordance with EPA 40 CFR Part 261, specifically Subpart B, in order to determine the appropriate local, state and federal requirements for disposal.

Use large volume of concentrated solution of ferrous salt or bisulfite solution as reducing agent. Then neutralize and flush to sewer with abundant water.

9191 143(hydrate, frozen)

49 181 10; Chlorine dioxide hydrate, frozen

No person may /transport,/ offer or accept a hazardous material for transportation in commerce unless that person is registered in conformance ... and the hazardous material is properly classed, described, packaged, marked, labeled, and in condition for shipment as required or authorized by ... /the hazardous materials regulations (49 CFR 171-177)./

Oxidizer Poison

Symbol: O, T+, N; R: 6-8-26-34-50; S: (1/2)-23-26-28-36/37/39-38-45-61