Registration Dossier
Registration Dossier
Diss Factsheets
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EC number: 233-162-8 | CAS number: 10049-04-4
- Life Cycle description
- Uses advised against
- Endpoint summary
- Appearance / physical state / colour
- Melting point / freezing point
- Boiling point
- Density
- Particle size distribution (Granulometry)
- Vapour pressure
- Partition coefficient
- Water solubility
- Solubility in organic solvents / fat solubility
- Surface tension
- Flash point
- Auto flammability
- Flammability
- Explosiveness
- Oxidising properties
- Oxidation reduction potential
- Stability in organic solvents and identity of relevant degradation products
- Storage stability and reactivity towards container material
- Stability: thermal, sunlight, metals
- pH
- Dissociation constant
- Viscosity
- Additional physico-chemical information
- Additional physico-chemical properties of nanomaterials
- Nanomaterial agglomeration / aggregation
- Nanomaterial crystalline phase
- Nanomaterial crystallite and grain size
- Nanomaterial aspect ratio / shape
- Nanomaterial specific surface area
- Nanomaterial Zeta potential
- Nanomaterial surface chemistry
- Nanomaterial dustiness
- Nanomaterial porosity
- Nanomaterial pour density
- Nanomaterial photocatalytic activity
- Nanomaterial radical formation potential
- Nanomaterial catalytic activity
- Endpoint summary
- Stability
- Biodegradation
- Bioaccumulation
- Transport and distribution
- Environmental data
- Additional information on environmental fate and behaviour
- Ecotoxicological Summary
- Aquatic toxicity
- Endpoint summary
- Short-term toxicity to fish
- Long-term toxicity to fish
- Short-term toxicity to aquatic invertebrates
- Long-term toxicity to aquatic invertebrates
- Toxicity to aquatic algae and cyanobacteria
- Toxicity to aquatic plants other than algae
- Toxicity to microorganisms
- Endocrine disrupter testing in aquatic vertebrates – in vivo
- Toxicity to other aquatic organisms
- Sediment toxicity
- Terrestrial toxicity
- Biological effects monitoring
- Biotransformation and kinetics
- Additional ecotoxological information
- Toxicological Summary
- Toxicokinetics, metabolism and distribution
- Acute Toxicity
- Irritation / corrosion
- Sensitisation
- Repeated dose toxicity
- Genetic toxicity
- Carcinogenicity
- Toxicity to reproduction
- Specific investigations
- Exposure related observations in humans
- Toxic effects on livestock and pets
- Additional toxicological data

Flammability
Administrative data
Link to relevant study record(s)
- Endpoint:
- flammable solids
- Data waiving:
- study technically not feasible
- Justification for data waiving:
- the study does not need to be conducted because the substance is a liquid
- Endpoint:
- flammable gases
- Type of information:
- not specified
- Adequacy of study:
- other information
- Reliability:
- 4 (not assignable)
- Rationale for reliability incl. deficiencies:
- secondary literature
- Remarks:
- Data comes from reviews using secondary data sources, and therefore cannot be assigned as reliable.
- Reason / purpose for cross-reference:
- reference to same study
- Reason / purpose for cross-reference:
- reference to other study
- Principles of method if other than guideline:
- No data.
- Parameter:
- lower explosion limit
- Value:
- > 10 % (not further specified)
- Remarks on result:
- other: %v/v at atmospheric pressure
- Executive summary:
The international CICAD review and the OECD SIDS report provide a lower explosion limit (LEL) of 10%v/v for the gas Chlorine dioxide, from the Merck Index.
- Endpoint:
- flammable gases
- Type of information:
- not specified
- Adequacy of study:
- other information
- Reliability:
- 4 (not assignable)
- Rationale for reliability incl. deficiencies:
- secondary literature
- Remarks:
- Data comes from a sheet with no reference to data sources, and therefore cannot be assigned as reliable.
- Reason / purpose for cross-reference:
- reference to same study
- Principles of method if other than guideline:
- No data.
- Parameter:
- lower explosion limit
- Value:
- > 10 % (not further specified)
- Remarks on result:
- other: vol% in air
- Executive summary:
The ICSC provides information on explosive limits, with a LEL >10%vol in air for the substance Chlorine dioxide.
- Endpoint:
- flammability
- Type of information:
- not specified
- Adequacy of study:
- other information
- Reliability:
- 4 (not assignable)
- Rationale for reliability incl. deficiencies:
- secondary literature
- Remarks:
- Data comes from an online compilation using secondary data sources, and therefore cannot be assigned as reliable. However, please note that the endpoint is cited in the database as peer reviewed.
- Reason / purpose for cross-reference:
- reference to same study
- Reason / purpose for cross-reference:
- reference to other study
- Principles of method if other than guideline:
- No data.
- Executive summary:
The HSDB database provides information on the fire potential of Chlorine dioxide: the substance can ignite from 130°C if concentration is higher than 10%.
- Endpoint:
- flammable gases
- Adequacy of study:
- other information
- Reliability:
- 4 (not assignable)
- Rationale for reliability incl. deficiencies:
- secondary literature
- Remarks:
- The publication summarises observations from other references, but doesn't provide experimental details; therefore it cannot be assigned as reliable.
- Reason / purpose for cross-reference:
- reference to same study
- Reason / purpose for cross-reference:
- reference to other study
- Parameter:
- lower explosion limit
- Value:
- 35 % (not further specified)
- Remarks on result:
- other: 310 mm Hg
- Executive summary:
As an introduction to safety management in chlorine dioxide plants, this publication summarises observations from other references about explosive concentration of the substance, whether pure or diluted in air, and practical maximum recommended limit.
- Endpoint:
- flammable gases
- Type of information:
- not specified
- Adequacy of study:
- other information
- Reliability:
- 4 (not assignable)
- Rationale for reliability incl. deficiencies:
- secondary literature
- Remarks:
- Data comes from a book dedicated to chlorine dioxide, compiling very numerous literature references, but few experimental details are provided. Therefore it cannot be assigned as reliable
- Reason / purpose for cross-reference:
- reference to same study
- Reason / purpose for cross-reference:
- reference to other study
- Principles of method if other than guideline:
- No data.
- Parameter:
- lower explosion limit
- Value:
- 4 - 10 % (not further specified)
- Executive summary:
The Simpson's book, dedicated to chlorine dioxide, provides summaries of several studies on explosivity of the substance. For the gas, a lower explosion limit of 10%v/v is suggested, but can be lowered to 4% in case of ignition by sparks. For off-gassing of aqueous solution, a conservative safe upper limit for partial pressure of about 50 mm Hg (6666 Pa) is generally accepted, which can be controlled from concentration and temperature. Above 45°C, ClO2 vapor appears to always decompose.
- Endpoint:
- flammable gases
- Type of information:
- not specified
- Adequacy of study:
- other information
- Reliability:
- 4 (not assignable)
- Rationale for reliability incl. deficiencies:
- secondary literature
- Remarks:
- Data comes from a toxicological profile citing other data sources, and therefore cannot be assigned as reliable. However, please note that secondary source is considered as peer reviewed.
- Reason / purpose for cross-reference:
- reference to same study
- Reason / purpose for cross-reference:
- reference to other study
- Principles of method if other than guideline:
- No data.
- Parameter:
- lower explosion limit
- Value:
- > 10 % (not further specified)
- Remarks on result:
- other: %v/v at 1 atm
- Executive summary:
The peer reviewed ATSDR profile for the substance Chlorine dioxide provides information relating to its explosive limits.
- Endpoint:
- flammable gases
- Type of information:
- experimental study
- Adequacy of study:
- other information
- Reliability:
- 2 (reliable with restrictions)
- Rationale for reliability incl. deficiencies:
- study well documented, meets generally accepted scientific principles, acceptable for assessment
- Remarks:
- This experimental study does not follow internationally recognised guidelines, and therefore cannot be fully reliable. It is nevertheless well documented, and acceptable under the test conditions.
- Reason / purpose for cross-reference:
- reference to same study
- Principles of method if other than guideline:
- A thermoregulated vessel, with pressure recording, is filled with chloride dioxide produced in-situ. Ignition is achieved with an AC electric arc.
- GLP compliance:
- no
- Parameter:
- lower explosion limit
- Value:
- 5.6 % (not further specified)
- Remarks on result:
- other: partial pressure of 10 mbar at a total of 170-180 mbar (molar fraction equivalent to %vol)
- Parameter:
- upper explosion limit
- Remarks on result:
- not measured/tested
- Conclusions:
- In particular conditions, chlorine dioxide can explode at partial pressure as low as 1000 Pa (eq. to a concentration of 5.6%vol).
- Executive summary:
Explosion trials with ClO2, conducted according to a non-standardised method, indicate that this gas is very sensitive to an (AC) electric arc as ignition source. Decomposition was recorded with only 10 mbar of ClO2 at a total of 170-180 mbar, the rest being mostly water vapour. This is far below what is normally said to be the lower explosion limit (ca 80 mbar). This was supposed to be due to the high energy and/or UV release of the ignition source.
The initiation period before explosion and the time to reach maximum pressure are longer, the lower the ClO2 pressure is. The pressure rise factor (Pmax/Pstart) decreases linearly with the ClO2 pressure. Water was confirmed to be a good inhibitor.
- Endpoint:
- flammable gases
- Type of information:
- not specified
- Adequacy of study:
- other information
- Reliability:
- 4 (not assignable)
- Rationale for reliability incl. deficiencies:
- secondary literature
- Remarks:
- The reference cites only endpoint information as a secondary source, and therefore cannot be assigned as reliable.
- Reason / purpose for cross-reference:
- reference to same study
- Reason / purpose for cross-reference:
- reference to other study
- Parameter:
- lower explosion limit
- Value:
- 11 % (not further specified)
- Executive summary:
This publication cites, as a secondary source, data on the explosive portential for the gas chlorine dioxide: a general limit of 11% is set, which can be lowered to 4% in case of ignition by electric sparks.
- Endpoint:
- flammable gases
- Type of information:
- not specified
- Adequacy of study:
- other information
- Reliability:
- 4 (not assignable)
- Rationale for reliability incl. deficiencies:
- data from handbook or collection of data
- Remarks:
- Data comes from a handbook using secondary data sources, and therefore cannot be assigned as reliable. However, please note that it is a compilation of numerous information, and considered as a reference among literature on hazardous reactions.
- Reason / purpose for cross-reference:
- reference to same study
- Reason / purpose for cross-reference:
- reference to other study
- Principles of method if other than guideline:
- No data.
- Parameter:
- lower explosion limit
- Value:
- > 7 % (not further specified)
- Executive summary:
The Bretherick's handbook compiles information on explosive potential of Chlorine dioxide, including data on LEL = 10% in air for any source of initiation, and even 7-8% if sparks.
- Endpoint:
- substances / mixtures which in contact with water emit flammable gases
- Data waiving:
- study scientifically not necessary / other information available
- Justification for data waiving:
- the study does not need to be conducted because the experience in production or handling shows that the substance does not react with water, e.g. the substance is manufactured with water or washed with water
- Justification for type of information:
- Flammability if contact with water is of no concern, based on the weight of evidence that the substance is generated as aqueous solution.
Referenceopen allclose all
Chlorine dioxide gas is explosive in concentrations in excess of 10% v/v at atmospheric pressure and will easily be detonated by sunlight or heat.
Concentrations above 10% can ignite at 130 deg C. Oxidizable organic dusts can lower decomposition temperature.
In Torregrossa's paper (9), experiments were done with ClO2/air mixtures: detonation was never observed, even up to 35% v/v in air (310 mm Hg), even though Haller & Northgraves (1) did observe it at partial pressures above 300 mm Hg.
The unknown and presumed dangerous area is with pure ClO2 at pressures above about 130 mm Hg, and diluted in air at atmospheric pressure or higher with partial pressure above 300 mm Hg.
In practice, values above 100 mm Hg are carefully avoided.
Gaseous ClO2
Depending upon its concentration in the vapour phase, chlorine dioxide can undergo a spontaneous autodecomposition reaction depending on partial pressure and temperature. At concentrations above about 4% in the air, a spark can cause a decomposition reaction with evolution of a small amount of energy [Rosenblatt 1976]. At ambient temperature, e.g. < 30°C, and concentrations above about 10%, the gas may undergo a spontaneous decomposition reaction (with a long induction period) commonly referred to as a "puff" [Gall 1976; Gray and Ip 1972; Haller and Northgraves 1955; Ip and gray 1972; McHale and von Elbe 1968; Noack and Doerr 1979; Paillard et al. 1986; Schumacher and Stieger 1930], because its flame propagation if ca 1 m/s, when compared to the flame propagation wave of an explosion, i.e., ca 300 m/s, is relatively quite slow.
As the concentration of chlorine dioxide in the vapour state increases, the violence of this reaction increases. At a concentration about 17% in the vapour state, the explosion becomes quite energetic, to the point where rapid, unscheduled disassembly of equipment can occur. However, a concentration of about 20% chlorine dioxide has been produced in the vapour space routinely with no problem [Haller and Northgraves 1955].
Gaseous ClO2 can decompose with a "puff" at partial pressures at or above 80 mm Hg.
Aqueous solutions of ClO2
Henry's law states that a gas dissolved in solution will distribute itself into the vapour phase in proportion to its concentration in solution. Therefore, the safe solubility of ClO2 depends upon temperature and pressure, and thus, by controlling the concentration of chlorine dioxide in solution, the partial pressure of chlorine dioxide can be controlled. That is, if the aqueous concentration of chlorine dioxide is kept below certain well established limits, chlorine dioxide cannot achieve that concentration in the vapour phase which can "puff". At 25°C and 30 mm partial pressure, it is safely soluble to the extent of about 3 g/L. What this means is that a solution of about 3 g/L concentration can be placed in a sealed container with an air space, and ClO2 will achieve a concentration in the air space according to Henry's law (54 atm at 20°C) that will not, at 25°C, undergo a "puff" (explosive decomposition). Relatively high concentrations of ClO2 can be stored safely for long periods, as long as there is no air space for the ClO2 gas to form.
Below about 30°C, if the partial pressure of chlorine dioxide is kept below about 50 mm Hg, and if organics or other impurities are not present, an explosive concentration of chlorine dioxide in the vapour space cannot be achieved [Ingols and Ridenour 1948a; McHale and von Elbe 1968].
Above about 45°C (the lower temperature limit), ClO2 vapour appears to always decompose, regardless of its partial pressure.
Explosive at temperatures >-40 °C [1] and concentrations in excess of 10% v/v at 1 atm [2].
The experiments and their results are summarized in the following tables, showing the dependence of tinit, and tPmax and f on the partial pressure of ClO2 and water.
N° |
Date |
GA |
Temp (°C) |
Cooling |
Water inj (µL) |
Pressure (mbar) registered |
Pressure (mbar) corrected |
Ignition |
Explosion times (ms) |
Explosion pressures (mbar) |
f |
|||||||||||
In |
Surf |
°C |
PH2O (mbar) |
ClO2 |
Air |
H2O |
Total |
ClO2 |
Air |
H2O |
Total |
(sec) |
(J) |
tinit |
tPmax |
Pmax |
Pfinal |
|||||
A |
20.9 |
102 |
72.8 |
76.0 |
11 |
13 |
150 |
102 |
5 |
90 |
197 |
89 |
5 |
103 |
197 |
0.35 |
14 |
10 |
15 |
760 |
236 |
3.9 |
C |
|
|
|
|
|
|
150 |
110 |
5 |
91 |
206 |
97 |
5 |
104 |
206 |
|
|
7 |
14 |
520 |
259 |
2.5 |
1 |
27.9 |
|
67.0 |
75.6 |
11 |
13 |
250 |
50 |
7 |
197 |
254 |
37 |
7 |
210 |
254 |
0.35 |
14 |
15 |
45 |
550 |
264 |
2.2 |
2 |
|
112 |
|
75.8 |
|
|
200 |
49 |
8 |
142 |
199 |
36 |
8 |
155 |
199 |
|
|
12 |
30 |
500 |
200 |
2.5 |
3 |
|
|
68.4 |
75.8 |
|
|
200 |
44 |
7 |
160 |
211 |
31 |
7 |
173 |
211 |
|
|
15 |
42 |
470 |
225 |
2.2 |
4 |
|
|
70.0 |
75.6 |
11 |
13 |
200 |
40 |
4 |
166 |
210 |
27 |
4 |
179 |
210 |
|
|
15 |
49 |
450 |
220 |
2.1 |
5 |
|
|
70.2 |
75.9 |
|
|
200 |
36 |
25 |
120 |
181 |
23 |
25 |
133 |
181 |
|
|
15 |
45 |
400 |
194 |
2.2 |
6 |
|
101 |
70.2 |
75.9 |
11 |
13 |
200 |
36 |
8 |
162 |
206 |
23 |
8 |
175 |
206 |
|
|
15 |
62 |
410 |
216 |
2.0 |
7 |
|
|
71.1 |
76.0 |
|
|
300 |
36 |
7 |
191 |
234 |
23 |
7 |
204 |
234 |
|
|
30 |
85 |
410 |
- |
1.8 |
8 |
|
|
71.1 |
76.0 |
|
|
300 |
36 |
5 |
215 |
256 |
23 |
5 |
228 |
256 |
|
|
35 |
92 |
430 |
263 |
1.7 |
9 |
|
|
|
76.8 |
11 |
13 |
200 |
97 |
6 |
120 |
223 |
84 |
6 |
133 |
223 |
|
|
40 |
- |
850 |
263 |
3.8 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
12 |
28.11 |
101 |
12 |
10 |
6 |
9 |
- |
24 |
|
|
24 |
15 |
|
9 |
24 |
0.35 |
14 |
8 |
18 |
84 |
- |
3.5 |
13 |
|
|
18 |
18 |
|
|
- |
21 |
|
|
21 |
12 |
|
9 |
21 |
|
|
- |
- |
ca80 |
31 |
ca4 |
14 |
|
|
18 |
18 |
|
|
- |
23 |
|
|
23 |
14 |
|
9 |
23 |
|
|
10 |
12 |
117 |
32 |
5.1 |
15 |
29.11 |
102 |
33 |
42 |
6 |
9 |
- |
20 |
|
|
20 |
11 |
|
9 |
20 |
|
|
8 |
8 |
108 |
29 |
5.4 |
16 |
|
|
41 |
45 |
|
|
- |
19 |
|
|
19 |
10 |
|
9 |
19 |
|
|
12 |
15 |
83 |
24 |
4.4 |
17 |
|
|
41 |
45 |
|
|
- |
20 |
|
|
20 |
11 |
|
9 |
20 |
|
|
7 |
10 |
104 |
29 |
5.2 |
18 |
3.4 |
|
67.3 |
72.0 |
4 |
8 |
200 |
15 |
7 |
161 |
183 |
7 |
7 |
169 |
183 |
0.35 |
14 |
60 |
170 |
268 |
187 |
1.46 |
19 |
|
|
|
|
|
|
200 |
26 |
26 |
159 |
211 |
18 |
26 |
167 |
211 |
|
|
- |
- |
370 |
217 |
1.75 |
20 |
|
|
|
|
|
|
200 |
25 |
11 |
139 |
175 |
17 |
11 |
147 |
175 |
|
|
16 |
- |
370 |
190 |
2.11 |
21 |
18.4 |
|
67.0 |
71.5 |
4 |
8 |
200 |
19 |
18 |
143 |
170 |
11 |
18 |
151 |
170 |
0.35 |
14 |
40 |
125 |
275 |
ca180 |
1.62 |
22 |
|
|
|
|
|
|
200 |
21 |
21 |
150 |
192 |
13 |
21 |
158 |
192 |
|
|
- |
- |
301 |
201 |
1.50 |
23 |
|
|
|
|
|
|
200 |
21 |
13 |
141 |
175 |
13 |
13 |
149 |
175 |
|
|
25 |
100 |
300 |
188 |
1.60 |
Decomposition of the ClO2could not be avoided. Even with extremely low partial pressures (10 mbar and less), pressure increases of 50% (f ca 1.5) were registered. The pressure factor f rises with increasing partial pressure of ClO2. Time of initiation, tinit, and time for pressure increase tPmax, are strongly dependent on the ClO2partial pressure. It can also be stated that water is a very good inhibitor for the decomposition, a fact which is also mentioned in the literature. It should be pointed out that experiments N°12-17 with only 9 mbar, all of which emerging from NaClO2water solution, also were performed at lower temperatures and lower total pressures than the others.
As decomposition are taking place at partial pressures of ClO2 which are thought to be completely safe (based on literature), the equipment was controlled, the pressure transducers have been calibrated, no decomposition is registered on the oscilloscope with pure air in the explosion vessel. The conclusion has been that the ignition energy is too high. It is also well-known that an electric arc is producing a rather high amount of UV-light, which in the literature (McHale 1968, Crawford 1968) has been mentioned as a very potent decomposition source. According to the characteristics of the AC arc (see above), it is difficult to both calculate and regulate (decrease) the energy effectively. With an ignition time of 0.35 second, the nergy can be calculated to 2000 V x 20 mA x 0.35 sec = 14 J.
Concentration of ClO2 vapour at about 11% in air may give mild explosions or "puffs", and concentrations of over 4% in air may be set off by an electric spark to sustain a decomposition wave.
(...) it was stated that decomposition by sparking begins to become hazardous at concentrations of 7–8% in air [3], and that at 10% concentration in air (0.1 bar partial pressure) explosion may occur from any source of initiation energy, such as sunlight, heat or electrostatic discharge [5].
Description of key information
Chlorine dioxide gas: LEL = 4 (sparks) - 10 (any source of ignition) %v/v in air.
Key value for chemical safety assessment
- Flammability:
- not classified
Additional information
An experimental, non-standard, study is available, as well as numerous literature data regarding explosive properties of chlorine dioxide gas and safe management. A Lower Explosion Limit of 10 %v/v in air is generally recognised, except in case of ignition by sparks, where lower values, between 4 and 8%, are set. For safety reasons, the lowest concentration will be retained in the present dossier.
Flammability if contact with water is of no concern, based on the weight of evidence that the substance is generated as aqueous solution.
Justification for classification or non-classification
Solution of chlorine dioxine generated in-situ at less than 2% in water (as registered): This endpoint does not apply to the substance as registered (aqueous solution generated in-situ), as liquid.
Other information: The gas has a Harmonised Classification as Oxidising, therefore it does not need to be classified in any other hazard class.
Information on Registered Substances comes from registration dossiers which have been assigned a registration number. The assignment of a registration number does however not guarantee that the information in the dossier is correct or that the dossier is compliant with Regulation (EC) No 1907/2006 (the REACH Regulation). This information has not been reviewed or verified by the Agency or any other authority. The content is subject to change without prior notice.
Reproduction or further distribution of this information may be subject to copyright protection. Use of the information without obtaining the permission from the owner(s) of the respective information might violate the rights of the owner.
