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SECTION 1. CHEMICAL IDENTIFICATION

CHEMINFO Record Number: 113
CCOHS Chemical Name: Sodium chlorate

Synonyms:
Chlorate of soda
Chloric acid, sodium salt

Chemical Name French: Chlorate de sodium
CAS Registry Number: 7775-09-9
UN/NA Number(s): 1495 2428
RTECS Number(s): FO0525000
EU EINECS/ELINCS Number: 231-887-4
Chemical Family: Inorganic halogen oxygen acid salt / inorganic halogen oxo acid salt / chlorine oxygen acid salt / chlorine oxo acid salt / chloric acid salt / chlorate / inorganic sodium compound / sodium salt
Molecular Formula: Cl-Na-O3
Structural Formula: Na.ClO3

SECTION 2. DESCRIPTION

Appearance and Odour:
White or colourless, odourless crystals, or granules (32); slightly hygroscopic (absorbs moisture from the air) (8,9).

Odour Threshold:
Odourless (32)

Warning Properties:
POOR: Odourless material.

Composition/Purity:
Sodium chlorate is available in crystalline or powder form, as a solution in water and as pre-blended sodium chlorate-sodium chloride solutions. Crystalline sodium chlorate is available in purity of 99 wt% and greater. Solutions are available containing about 25-50% sodium chlorate, and about 350 g/L sodium chlorate (3.3 M), about 200 g/L sodium chloride (3.4 M) and 190 ppm chromium; or about 600 g/L sodium chlorate (5.6 M), about 30 g/L sodium chloride (0.5 M) and less than 90 ppm chromium. Typical impurities include sodium chloride, moisture, chromium and small amounts of sodium sulfate, sodium dichromate, and potassium bromate.(8,19)

Uses and Occurrences:
Sodium chlorate is mainly used for the on-site production of chlorine dioxide. The second most important use is as an intermediate in the production of other chlorates, mainly potassium chlorate, and perchlorates. It is also used as an oxidizing agent in uranium refining and other metallurgical operations; as a non-selective agricultural herbicide for control of grasses and broadleaf weeds; as a defoliant for cotton; as a defoliant/desiccant and/or harvest aid on grain sorghum, rice, soybeans, flax, sunflowers and certain other crops; to kill trees and stumps; as an oxidizing agent in the chemical industry; as an additive to agricultural products and dyes; in textile and fur dyeing; in metal etching; in the production of oxygen in rescue breathing apparatus; for tanning and finishing leather; and as an analytical reagent.(1,8,19,32)
The chlorate ion is a by-product of chlorine dioxide disinfection of drinking water.(12)


SECTION 3. HAZARDS IDENTIFICATION

EMERGENCY OVERVIEW:
White or colourless, odourless crystals or granules. Slightly hygroscopic. Does not burn. Decomposes explosively under intense fire conditions forming oxygen, chlorine and hydrogen chloride gas. STRONG OXIDIZER. Promotes combustion. Mixtures with combustible or flammable materials (dry organic materials) can be ignited readily by heat, shock or friction, and/or explode. Can form shock-, heat- or friction-sensitive mixtures with finely divided metals, metal salts, ammonium salts, non-metals, strong reducing agents and sulfides. TOXIC. Harmful if swallowed.

Important New Information:
NOTE: The evaluation of this chemical as TOXIC is under review. For additional information, contact the CHEMINFO team at cheminfo@ccohs.ca.



POTENTIAL HEALTH EFFECTS

Effects of Short-Term (Acute) Exposure

Inhalation:
Sodium chlorate does not form a vapour and the dust is unlikely to be inhaled since it absorbs moisture from the air forming a pasty solid. Any airborne dust or mists formed from solutions may cause coughing and mild temporary irritation of nose and throat. There is no specific human or animal inhalation information available.

Skin Contact:
The solid material and concentrated solutions probably cause only mild irritation based on animal information. There is no human information available.

Eye Contact:
Dusts or mists probably cause slight eye irritation, based on limited animal information. Some tearing, blinking and mild, temporary pain may occur as the solid material is rinsed from the eye by tears. There is no human information available.

Ingestion:
Incidents of non-occupational chlorate poisoning have shown that sodium chlorate can cause a harmful effect on the blood (methemoglobinemia), harmful effects on the kidneys, and death. Based on case reports, various authors have published estimated human lethal doses ranging from 210-430 mg/kg. Death has resulted from ingestion of as little as 7.5 grams (corresponding to 110 mg/kg for a 70 kg man). However, another case is reported in which vigorous treatment saved a person who had ingested about 40,000 mg (570 mg/kg).(9,15,16)
Initial symptoms of poisoning may include headache, fatigue, respiratory difficulty, nausea, vomiting and abdominal pain. These symptoms may be delayed as much as 12 hours after ingestion.(16,17,18,36,37) In two case reports, the victims developed a blue discolouration (cyanosis) of the skin and produced dark urine and/or had dark brown-coloured blood. These are signs of methemoglobinemia. In both cases, death occurred due to cardiac arrest within hours of arriving at the hospital.(36,37) Animal studies show that sodium chlorate is less toxic to animals than to humans, although similar effects to those observed in humans have been observed at higher doses in studies using dogs. Ingestion is not a typical route of occupational exposure.

Effects of Long-Term (Chronic) Exposure

Blood/Blood Forming System:
There is an unconfirmed report of elevated methemoglobin levels (less than 10% increases) in workers exposed to sodium chlorate. Levels of exposure were not reported.(16, unconfirmed) There are insufficient details available in English to permit evaluation of this study.

INGESTION : No significant harmful effects were observed in a 16-day rising dose study with men who ingested 1000 mL of a sodium chlorate solution, first at 0.01 mg/L, increasing every third day to 0.5, 1.0, 1.8 and 2.4 mg/L, or in men who ingested 500 mL (5 mg/L) daily for 12 weeks.(39) Ingestion is not a typical route of occupational exposure.

Carcinogenicity:

There is no relevant human or animal information available.

The International Agency for Research on Cancer (IARC) has not evaluated the carcinogenicity of this chemical.

The American Conference of Governmental Industrial Hygienists (ACGIH) has no listing for this chemical.

The US National Toxicology Program (NTP) has not listed this chemical in its report on carcinogens.

Teratogenicity and Embryotoxicity:
There is no human information available. Animal information indicates that sodium chlorate does not cause developmental toxicity.

Reproductive Toxicity:
There is no human information available. No harmful effects were observed in one limited animal study.

Mutagenicity:
There is no human information available. The available animal information indicates that sodium chlorate is not mutagenic.

Toxicologically Synergistic Materials:
There is no information available.

Potential for Accumulation:
Sodium chlorate probably does not accumulate in the body. Chlorates are readily absorbed from the gut and are rapidly excreted unchanged by the kidneys, the excretion being complete in 2 days.(1)


SECTION 4. FIRST AID MEASURES

Inhalation:
If symptoms are experienced, remove source of contamination or move victim to fresh air. If symptoms persist, obtain medical advice.

Skin Contact:
As quickly as possible, flush contaminated area with lukewarm, gently running water for at least 5 minutes, or until the chemical is removed. Under running water, remove contaminated clothing, shoes and leather goods (e.g. watchbands, belts). If irritation persists, repeat flushing. Obtain medical advice immediately. Completely decontaminate clothing, shoes and leather goods before re-use or discard. NOTE: Clothing contaminated with sodium chlorate solutions is a serious fire hazard if allowed to dry. Immediately immerse item(s) in water. Keep thoroughly wet until discarded or laundered. Inform laundry personnel of contaminant's hazards.

Eye Contact:
SOLUTIONS: Immediately flush the contaminated eye(s) with lukewarm, gently flowing water for 5 minutes, or until the chemical is removed, while holding the eyelid(s) open. If irritation persists, obtain medical advice. SOLIDS: DO NOT allow victim to rub eye(s). Let the eye(s) water naturally for a few minutes. Have victim look right and left, and then up and down. If particle/dust does not dislodge, flush with lukewarm, gently flowing water for 5 minutes or until particle/dust is removed, while holding the eyelid(s) open. If irritation persists, obtain medical attention. DO NOT attempt to manually remove anything stuck to the eye(s).

Ingestion:
NEVER give anything by mouth if victim is rapidly losing consciousness, or is unconscious or convulsing. Have victim rinse mouth thoroughly with water. DO NOT INDUCE VOMITING. Have victim drink 240 to 300 mL (8 to 10 oz) of water. If vomiting occurs naturally, rinse mouth and repeat administration of water. Obtain medical attention immediately.

First Aid Comments:
All first aid procedures should be periodically reviewed by a doctor familiar with the material and its conditions of use in the workplace.

Note to Physicians:
The typical antidote for methemoglobinemia, methylene blue is not always effective in the treatment of methemoglobinemia associated with chlorate poisoning.(37)



SECTION 5. FIRE FIGHTING MEASURES

Flash Point:
Not combustible (does not burn).

Lower Flammable (Explosive) Limit (LFL/LEL):
Not applicable

Upper Flammable (Explosive) Limit (UFL/UEL):
Not applicable

Autoignition (Ignition) Temperature:
Not applicable

Sensitivity to Mechanical Impact:
Pure sodium chlorate is not sensitive to mechanical impact.

Sensitivity to Static Charge:
Pure sodium chlorate will not accumulate static charge. Since it does not burn, it will not be ignited by static discharge.

Electrical Conductivity:
Approximately 15.5 X 10(12) pS/m (50-60% solutions).(8,19)

Combustion and Thermal Decomposition Products:
Pure sodium chlorate decomposes explosively under intense fire conditions.(21) It initially decomposes to sodium perchlorate and begins to liberate oxygen at about 265 deg C.(8,9) Besides oxygen, other compounds formed in a fire include chlorine, hydrogen chloride and sodium oxide.

Fire Hazard Summary:
Sodium chlorate is not combustible (does not burn). However, it is a strong oxidizing agent and is a serious fire and explosion risk, especially when contaminated with dry combustible organic materials (e.g. cloth, grease, leather, oil, paper, sawdust and wood). Contaminated materials can be ignited readily by heat, friction or shock. Sodium chlorate decomposes at about 265 deg C giving off oxygen, which promotes combustion. Large amounts of oxygen will form an oxygen-rich atmosphere. The accompanying increase in the rate of burning and flame temperature can have catastrophic consequences.(9,21) Closed containers may rupture violently due to rapid decomposition, if exposed to fire or excessive heat for a sufficient period of time. DO NOT heat any part of a sodium chlorate container to 49 deg C (120 deg F).(22) During a fire, corrosive chlorine and hydrogen chloride gas may be generated.

Extinguishing Media:
Sodium chlorate does not burn. Extinguish fire using extinguishing agents suitable for the surrounding fire and not contraindicated for use with sodium chlorate. Sodium chlorate is an oxidizing agent. Therefore, flooding quantities of water spray or fog should be used to fight fires involving sodium chlorate.(8,20)

Extinguishing Media to be Avoided:
DO NOT use dry chemical fire extinguishing agents containing ammonium compounds (such as some A:B:C agents), since an explosive compound can be formed. DO NOT use carbon dioxide, dry chemical powder or other extinguishing agents that smother flames, since they are not effective in extinguishing fires involving oxidizers.(22)

Fire Fighting Instructions:
Extreme caution is required in a fire situation. Evacuate area and fight fire from a protected, explosion-resistant location or maximum possible distance. Approach fire from upwind to avoid hazardous decomposition products, such as chlorine and hydrogen chlorine. Wear full protective suit if exposure is possible. See Protection of Firefighters.
If possible, isolate materials not involved in the fire, if this can be done without risk, and protect personnel. If sodium chlorate is not involved in the fire, move chlorate containers from the fire area only if they have not been exposed to heat. Decomposes explosively under intense fire conditions. Use extreme caution since heat may rupture containers. Otherwise, apply water from as far a distance as possible, in flooding quantities as a spray or fog to keep fire-exposed containers or equipment cool and absorb heat, until well after the fire is out.
Remove all flammable and combustible materials from the vicinity, especially oil and grease. Do not direct water directly on leak as this may cause leak to increase. Stay away from ends of tanks, but realize that shrapnel may travel in any direction. Withdraw immediately in case of rising sound from venting safety device or any discolouration of tanks due to fire. In an advanced or massive fire, the area should be evacuated. Use unmanned hoseholders or monitor nozzles.
Tanks or drums should not be approached directly after they have been involved in a fire or heated by exposure, until they have been completely cooled down. Clean-up or salvage operations should not be attempted until the sodium chlorate is cooled.

Protection of Fire Fighters:
The decomposition products of sodium chlorate, such as chlorine and hydrogen chloride, are extremely hazardous to health. Do not enter without wearing specialized protective equipment suitable for the situation. Firefighter's normal protective equipment (Bunker Gear) will not provide adequate protection. Chemical resistant clothing (e.g. chemical splash suit and positive pressure self- contained breathing apparatus (NIOSH approved or equivalent) may be necessary.



NATIONAL FIRE PROTECTION ASSOCIATION (NFPA) HAZARD IDENTIFICATION

NFPA - Comments:
NFPA has no listing for this chemical in Codes 49 or 325.


SECTION 9. PHYSICAL AND CHEMICAL PROPERTIES

Molecular Weight: 106.44

Conversion Factor:
Not applicable

Physical State: Solid
Melting Point: 248 deg C (478.4 deg F) (23,33)
Boiling Point: Begins to decompose at 265 deg C (509 deg F) (8,9)
Relative Density (Specific Gravity): 2.487 at 25 deg C (water = 1) (8,19)
Solubility in Water: Very soluble (96-100 g/100 mL water at 20 deg C) (23,24)
Solubility in Other Liquids: Soluble in glycerin and liquid ammonia; slightly soluble in ethanol.(23,33)
Coefficient of Oil/Water Distribution (Partition Coefficient): Log P(oct) = -7.18 (estimated) (25)
pH Value: Neutral (solution in water) (32)
Vapour Density: Not applicable
Vapour Pressure: Does not form a vapour.
Saturation Vapour Concentration: Does not form a vapour.
Evaporation Rate: Not applicable
Critical Temperature: Not applicable

SECTION 10. STABILITY AND REACTIVITY

Stability:
Stable at normal temperatures and pressure. At low pH, solutions decompose forming corrosive and dangerously reactive chlorine dioxide.(20,21)

Oxidizing Properties:
Sodium chlorate is listed by the NFPA as a Class 3 oxidizing material. A Class 3 oxidizer will cause a severe increase in the burning rate of combustible materials with which it comes in contact or that will undergo vigorous self-sustained decomposition due to contamination or exposure to heat.(22) The oxidizing activity of sodium chlorate solutions increases with decreasing pH (acidity). Concentrated acidic solutions are vigorous oxidizing agents due to the formation of chloric acid. Alkaline chlorate solutions do not exhibit strong oxidizing properties.(19)

Hazardous Polymerization:
Does not occur.

Incompatibility - Materials to Avoid:

NOTE: Chemical reactions that could result in a hazardous situation (e.g. generation of flammable or toxic chemicals, fire or detonation) are listed here. Many of these reactions can be done safely if specific control measures (e.g. cooling of the reaction) are in place. Although not intended to be complete, an overview of important reactions involving common chemicals is provided to assist in the development of safe work practices.


ORGANIC MATTER (e.g. charcoal, cloth, flour, greases, leather, oils, paint, paper, sawdust, shellac, sugar and wood) - mixtures may ignite readily or explode. Mixtures may be very sensitive to shock, heat or friction and may ignite spontaneously and burn with explosive violence.(9,20,21)
AGRICULTURAL MATERIALS (e.g. peat, powdered sulfur, urotropine (hexamethylenetetramine), thiuram and other formulated materials) - mixtures with sodium chlorate-based herbicides may undergo explosive combustion.(21)
STRONG ACIDS (e.g. concentrated sulfuric acid) or DIBASIC ORGANIC ACIDS - may explode violently due to the formation of dangerously reactive chlorine dioxide gas.(20,21)
SULFUR DIOXIDE - evolves sulfur peroxide, which flashes at 60 deg C and can explode.(20)
AMMONIUM SALTS (e.g. ammonium thiosulfate), FINELY DIVIDED METALS (e.g. aluminum, copper, titanium or zinc), METAL SALTS (especially copper), STRONG REDUCING AGENTS (e.g. calcium hydride or strontium hydride), or SULFIDES (e.g. antimony sulfide, arsenic sulfide, copper sulfide or tin sulfide) - may react violently or explosively, either spontaneously (especially in presence of moisture) or on initiation by heat, friction, impact, sparks or addition of sulfuric acid.(20,21)
NON-METALS (e.g. arsenic, red and white phosphorus, silicon or sulfur) - mixtures are powerfully explosive and dangerously sensitive to friction or shock; spontaneous ignition sometimes occurs.(20,21)
METAL CYANIDES (e.g. potassium cyanide) - can explode when heated.(20,21)
MANGANESE DIOXIDE - yields oxygen when heated above 70 deg C; strong production of oxygen at 100 deg C. Reaction may be explosive and may be initiated by heat, shock, friction, age or static electricity.(8,20)
NITROBENZENE - mixture is powerfully explosive (21)
ARSENIC TRIOXIDE - ignition may occur on contact.(21)

Hazardous Decomposition Products:
None reported.

Conditions to Avoid:
Heat, sparks, friction, shock, impact, open flames, contact with combustible materials, acidic pH

Corrosivity to Metals:
Sodium chlorate solutions are corrosive to steel (to 50% concentration), cast iron (to 50%), Hastelloy B/B-2 and D, and zinc. They are not corrosive (penetration less than 2 mils (50 um)/year) to nickel and its alloys (10-70% solutions), Hastelloy C/C-276 (to 70%) Inconel (10-70%), Incolloy (25%), Monel (10-70%), type 20-25-4.5 stainless steel, tantalum (10%), titanium and zirconium. Aluminum (to 70%), copper, brass, bronze, naval bronze, high silicon iron, and stainless steels (types 304/307 (50%), 316 (to 70%), 400 series and 20 Cb 3 (to 70%)) also have good resistance (less than 20 mils (505 um)/year).(26,27)

Corrosivity to Non-Metals:
Sodium chlorate does not attack most plastics, elastomers and coatings. However, it can attack some plastics (such as acetal copolymer (above 66 deg C), acrylonitrile-butadiene-styrene (ABS), nylon 6 and 66 and isophthalic polyester), elastomers (such as soft rubber, butyl rubber (above 66 deg C) and natural rubber).(26,28) Polytetrafluoroethylene (PTFE) and polyvinylidene fluoride (PVDF) (Kynar) have excellent resistance to sodium chlorate.(19)

Stability and Reactivity Comments:
Sodium chlorate solutions splashed on clothing should never be allowed to dry, because this would result in a serious fire hazard.(8)


SECTION 11. TOXICOLOGICAL INFORMATION

LC50 (rat): greater than 7000 mg/m3 (4-hour exposure); cited as greater than 28 mg/L (1-hour exposure) (administered as an aerosol of a 10.0% (w/v) water solution) (3)

LD50 (oral, rat): 1200 mg/kg (2,7-unconfirmed); 5210 mg/kg (3)

LD50 (dermal, rabbit): greater than 10000 mg/kg (3)

Eye Irritation:

Sodium chlorate is a slight irritant.

Slight irritation was observed in rabbits following application of 10 mg of the dry powder for an unspecified duration (scored 19.3/110 at 24 hours; 10.2/110 at 48 hours and 8.5/110 at 72 hours).(3)

Skin Irritation:

Sodium chlorate has caused no to slight irritation.

Slight redness (scored 1/4) and no swelling was observed in rabbits following application of 500 mg dry powder moistened with 0.1 mL water for an unspecified duration. Well-defined redness (scored 2/4) was observed in 3/6 rabbits following application to damaged (abraded) skin. These effects had cleared 48 hours later. The overall score was 0.62/8.0.(3) In another study, no skin reaction was observed following application of a 50% w/w sodium chlorate solution for 4 hours, under a patch.(4)

Effects of Short-Term (Acute) Exposure:

Ingestion:
Vomiting occurred within 15 minutes after administration of 1000 or 2000 mg/kg sodium chlorate (purity unspecified) to eight dogs for 45 minutes. No other effects were observed. Death resulted after one dog ingested 3300 mg/kg in drinking water over a 24-hour period and in another that ingested 308 mg/kg/day for 4 days. Another dog that received 326 mg/kg/day for 5 days survived. Both animals showed signs of kidney injury. Harmful effects on the blood (changes indicative of hemolysis) were observed in 2/6 dogs that received oral dosages of 200-275 mg/kg/day for 5 days.(6) In a similar study, vomiting and harmful effects on the blood system and the kidneys were observed in dogs that were given a one-time dose of 500-2000 mg/kg sodium chlorate. Deaths were observed at 2000 mg/kg (one dog) and at 1000 mg/kg in a dog with pre-existing kidney disease.(10) Reduced body weight was observed in rats fed 921 mg/kg/day sodium chlorate in the diet for 28 days. No other statistically significant, dose-related effects were observed. Feed consumption was somewhat lower at this dose level as well.(3) Rats were exposed to 0, 0.125, 0.25, 0.5, 1.0 and 2.0 g/L sodium chlorate in water for 21 days. Approximate concentrations were 0, 12.5, 25, 50, 100 or 200 mg/kg/day. Concentration-dependent thyroid changes (e.g. decreased colloid, hyperplasia of follicular cells and thyroid enlargement) were observed, with statistical significance at 50 mg/kg/day and above. Thyroid lesions were not observed in mice exposed in the same way.(35)

Effects of Long-Term (Chronic) Exposure:

Ingestion:
Harmful effects were observed in rats following ingestion of doses as low as 1.0 mg/kg/day for 9 months. However, rats appear to be susceptible to long-term sodium chlorate toxicity. Anemia (decreased red blood cell count and related effects on the blood) and decreased body weights were observed in rats that ingested drinking water containing 10 or 100 mg/L chlorate (approximately equal to 1.0 or 10 mg/kg/day sodium chlorate) for 9 months.(11) The study did not evaluate whether these effects reversed after exposure ended. Harmful effects of the blood (decreased red blood cell count and related effects) were observed in male rats that received 6.14 mMol chlorate/kg/day in drinking water (equivalent to 653 mg/kg/day sodium chlorate) for 90 days. Although the results in females exposed to higher doses (9.6 mMol chlorate/kg/day) were not statistically significant, there was evidence of a dose-related trend. Body weight and organ weight changes were also observed at doses of 6.14 mMol/kg/day (males) or 9.60 mMol/kg/day (females). The study did not evaluate whether these effects were reversible.(12) Rats were exposed to 0, 0.125, 0.25, 0.5, 1.0, 2.0 g/L for 4, 21 or 90 days. Approximate doses were 0, 12.5, 50, 100 or 200 mg/kg/day. Decreased serum levels of thyroid hormones (T3 and T4) were observed at 100 and 200 mg/kg/day after 4 days, but only at 200 mg/kg/day after 21 days. After 90 days, T3/T4 levels were not significantly different from the controls in any dose group. TSH was significantly increased in animals exposed to 200 mg/kg/day after 4, 21 and 90 days, but to a lesser extent after 90 days, indicating recovery or adaptation.(35) Male rats were exposed to 0, 0.001, 0.01, 0.1, 1.0 or 2.0 g/L for 90 days. Approximate doses were 0, 0.1, 1.0, 10, 100 or 200 mg/kg/day. Thyroid lesions (hypertrophy, decreased colloid) were observed at 0.1 mg/kg/day and higher, and follicular cell hyperplasia occurred at 100 and 200 mg/kg/day. Similar thyroid lesions were observed in female rats after 105 days of exposure to doses of 200 mg/kg/day. Rats are considered to be more susceptible than humans to thyroid-related disruption by chemicals. Thyroid effects were not observed in female mice exposed to 0, 100, 200, 400, 800 or 1200 mg/kg/day (cited as 0, 0.5, 1.0, 2.0, 4.0 or 6.0 g/L) sodium chlorate after 105 days of exposure.(35)

Teratogenicity, Embryotoxicity and/or Fetotoxicity:
The available information does not suggest that sodium chlorate causes developmental toxicity.
Rabbits were orally administered 0, 100, 250, or 475 mg/kg/day sodium chlorate in water from days 6-29 of pregnancy. Examination of fetuses showed no significant developmental toxicity (fetal body weight, litter size, external/internal malformations). Significant maternal toxicity was not observed, but urinary changes (orange or brown urine; and/or little or no urine) on one or more days of treatment was observed. The number of animals affected showed a dose-response pattern, but the changes were considered temporary and not clearly indicative of toxicity. The authors reported that maternal toxicity would be expected at 500 mg/kg/day or higher, based on a screening study.(34) No statistically significant harmful effects were observed in the offspring of groups of 9 rats given 1 mg/L or 10 mg/L chlorate (as sodium chlorate; equivalent to 0.2 to 2 mg/kg/day assuming an average body weight of 160 grams and drinking water consumption of 20 mL/day) in drinking water for 2.5 months prior to mating and during pregnancy. The significance of increased fetal length observed at the high dose is unclear.(13) This study was limited by small group size. In an unpublished study, rats were orally given 0, 10, 100 or 1000 mg/kg/day in distilled water on days 6-15 of pregnancy. No significant developmental effects or maternal toxicity was noted.(34, unconfirmed) There are no further details available for evaluation.

Reproductive Toxicity:
No conclusions can be drawn based on the available information.
No harmful effect on fertility was observed among groups of 9 female rats given 1 mg/L or 10 mg/L chlorate (as sodium chlorate; equivalent to 0.2 to 2 mg/kg/day assuming an average body weight of 160 grams and drinking water consumption of 20 mL/day) in drinking water for 2.5 months prior to mating and during pregnancy.(13) This study was limited by small group size.

Mutagenicity:
The available information does not suggest that sodium chlorate is mutagenic. Negative results were obtained in tests using live animals.
Negative results were obtained in tests involving oral administration of sodium chlorate to mice (tests were for chromosome aberrations, micronuclei in bone marrow or sperm shape abnormalities).(5) Another study also obtained negative results in a bone marrow micronucleus test with mice given two oral doses of 2128, 3192 or 4265 mg/kg or two intraperitoneal injections of 530, 1060 or 2120 mg/kg.(14,38)
Positive results were obtained in bacteria, with metabolic activation.(14,38) In other studies, negative results were obtained with bacteria, in the presence and absence of metabolic activation.(34, unconfirmed)
Positive results were obtained in a test using fruit flies.(14,38)


SECTION 16. OTHER INFORMATION

Selected Bibliography:
(1) US National Library of Medicine. Sodium chlorate. Last revision date: 2003-03-05. In: Hazardous Substances Data Bank (HSDB). CHEMpendium. [CD-ROM]. Canadian Centre for Occupational Health and Safety (CCOHS). Also available at: <ccinfoweb.ccohs.ca/chempendium/search.html>
(2) Edson, E.F. Applied toxicology of pesticides. The Pharmaceutical Journal. Vol. 185 (Oct. 15, 1960). p. 361-367
(3) Anonymous. Sodium chlorate. Data Sheet No. 24-3/71. Industrial Bio-test Laboratories, 1971
(4) Elf Atochem North America, Inc. Rabbit skin corrosivity screen of fifty-six products (including 4-tert-pentylphenol), with cover letter dated 5/23/96. EPA/OTS Document #86960000538. Pharmacology Research Inc., 1996
(5) Meier, J.R., et al. Evaluation of chemicals used for drinking water disinfection for production of chromosomal damage and sperm-head abnormalities in mice. Environmental Mutagenesis. Vol. 7 (1985). p. 201-211
(6) Heywood, R., et al. Toxicity of sodium chlorate to the dog. Veterinary Record. Vol. 90, no. 15 (Apr. 8, 1972). p. 416-418
(7) National Institute for Occupational Safety and Health (NIOSH). Chloric acid, sodium salt. Last updated: 2003-02. In: Registry of Toxic Effects of Chemical Substances (RTECS(R)). [CD-ROM]. Canadian Centre for Occupational Health and Safety (CCOHS). Also available at: <ccinfoweb.ccohs.ca/rtecs/search.html>
(8) Mendiratta, S.K., et al. Chlorine oxygen acids and salts: chloric acid and chlorates: sodium and potassium chlorate. In: Kirk-Othmer encyclopedia of chemical technology. 4th ed. Vol. 5. John Wiley and Sons, 1993. p. 1000-1016
(9) Anonymous. Storage and use of sodium chlorate. Guidance Note CS 3. Health and Safety Executive (UK), 1980
(10) Sheahan, B.J., et al. Experimental sodium chlorate poisoning in dogs. Research in Veterinary Science. Vol. 12, no. 4 (July 1971). p. 387-389
(11) Abdel-Rahman, M.S., et al. Toxicity of chlorine dioxide in drinking water. Journal of Environmental Pathology, Toxicology and Oncology. Vol. 6, no. 1 (1985). p. 105-113
(12) McCauley, P.T., et al. The effects of subchronic chlorate exposure in Sprague-Dawley rats. Drug and Chemical Toxicology. Vol. 18, no. 2/3 (May 1995). p. 185-199
(13) Suh, D.H., et al. Effect of chlorine dioxide and its metabolites in drinking water on fetal development in rats. Journal of Applied Toxicology. Vol. 3, no. 2 (1983). p. 75-79
(14) Eckhardt, K., et al. Mutagenic activity of chlorate, bromate and iodate. Abstract. Mutation Research. Vol. 97 (1982). p. 185
(15) Gosselin, R.E., et al. Chlorate salts. In: Clinical toxicology of commercial products. Williams and Wilkins, 1984. p. II-112
(16) W.J. Hayes, et al, eds. Sodium chlorate. In: Handbook of pesticide toxicology. Vol. 2. Academic Press, 1991. p. 565-566
(17) Steffen, C., et al. Severe chlorate poisoning: report of a case. Archives of Toxicology. Vol. 48, no. 4 (1981). p. 281-288
(18) Hutchinson, E.D. Suicidal chlorate poisoning treated with peritoneal dialysis. Unpublished. Summary of article by R.K. Knight, et al., British Medical Journal. Vol. 3, no. 5565 (1967). p. 601-605
(19) Vogt, H., et al. Chlorine oxides and chlorine oxygen acids: chloric acid and chlorates. In: Ullmann's encyclopedia of industrial chemistry. 5th completely rev. ed. Vol. A 6. VCH Verlagsgesellschaft, 1986. p. 501-514
(20) Fire protection guide to hazardous materials. 13th ed. Edited by A.B. Spencer, et al. National Fire Protection Association, 2002. NFPA 491 (Sodium chlorate and Chlorates)
(21) Urben, P.G., ed. Bretherick's reactive chemical hazards database. 6th ed. Version 3.0. Butterworth-Heinemann Ltd., 1999
(22) NFPA 430. Code for the storage of liquid and solid oxidizers. National Protection Association, 1995. p. 430-1 to 430-16
(23) Dean, J.A. Lange's handbook of chemistry. 15th ed. McGraw-Hill, Inc., 1999. p. 3.49
(24) The physical properties database (PHYSPROP). (URL: http://esc-plaza.syrres.com/interkow/PhysProp.htm)
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Information on chemicals reviewed in the CHEMINFO database is drawn from a number of publicly available sources. A list of general references used to compile CHEMINFO records is available in the database Help.


Review/Preparation Date: 2004-02-17

Revision Indicators:
Resistance of materials for PPE 2004-04-08
Bibliography 2004-11-21
EU classification 2004-11-21
EU risks 2004-11-21
EU safety 2004-11-21



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