SODIUM CHLORATE
HAZARDOUS MATERIALS
CHEMICAL DATA NOTEBOOK SERIES #48
Sodium chlorate is an oxidizing, toxic, slightly irritating, corrosive, reactive, pale yellow-to-white crystalline, odorless solid. It is a popular oxidizing agent used to make explosives, defoliants, flares, herbicides, matches, and pyrotechnics. It is also used to process ore and tan leather and in the manufacture of cosmetics, dyes, inks, paper, pharmaceuticals, and many other chemicals.
PROPERTIES
Sodium chlorate is nonflammable, has a specific gravity of 2.49, and has a molecular weight of 106.4. It melts at 478°F, decomposes before it boils, and is very soluble in water. It is considered a stable chemical at normal temperatures but will decompose at 572°F, liberating oxygen. The oxygen may be a secondary release after chlorine and sodium oxide are formed. Sodium chlorate’s chemical formula is NaClO*.
Sodium chlorate’s major hazard is that it is an oxidizer or oxidizing agent: Under certain circumstances it will liberate oxygen in a form available to support the burning of any combustible material. An oxidizing agent will make any ordinary combustible material burn very rapidly and make very combustible materials explosive.
For sodium chlorate, the liberation of oxygen occurs with very little input of energy—in fact, any input of energy, whether heat from a fire, impact shock, sparks, frictional heat, or the energy of a chemical reaction, will cause sodium chlorate to give up relatively large volumes of molecular oxygen (02). The intimate mixing of sodium chlorate with any fuel (anything that will burn) may provide the energy required to liberate oxygen and cause an explosion and/or fire. As little energy as walking on the material could initiate a reaction that causes your shoe soles to burst into flame. A confined mixture of sodium chlorate and the right amount and type of solid fuel resembles black powder in its ability to detonate. Therefore, sodium chlorate must never be stored near any combustible material, and the more isolated the storage area, the safer the operations. Good housekeeping when dealing with oxidizers is essential.
In addition to sodium chlorate’s potentially violent reaction to all organic materials, such as carbon, charcoal, grease, leather, paper, and wood, it will react violently’ or explosively or will ignite on contact with such materials as aluminum, ammonium salts, antimony sulfide, arsenic, arsenic trioxide, cyanides, dibasic organic acids, manganese dioxide, metal sulfides, nitrobenzene, phosphorus, powdered metals, sodium phosphinate, sulfur, sulfuric acid, thiocyanates, and zinc.
In some situations a water-soluble oxidizing agent such as sodium chlorate may be shipped as a solution containing 30 percent or more of the oxidizer. Any spilled solution can be a serious problem if the water is allowed to evaporate instead of being cleaned up thoroughly. The material left behind after the water has evaporated will be very fine, almost dustlike, and will become very reactive, giving up its oxygen at the slightest urging. Thus even though a water solution of sodium chlorate is inherently safer in transportation and storage, any release of the solution will make the material infinitely more mobile than the solid, crystalline material. Any spilled solution will percolate into the soil and carry its oxidizer deep into the ground or will intimately mix with any material it contacts aboveground.
Sodium chlorate is considered to be of relatively low toxic hazard during transportation and normal handling. However, make every effort to keep from ingesting the material. Ingestion may cause gastrointestinal damage, including severe pain, vomiting, and diarrhea. Ingesting as much as half an ounce of sodium chlorate may cause respiratory problems, damage to the liver and kidneys, and death.
Contact of the eyes with sodium chlorate may cause irritation or severe damage. Contact with the skin can cause irritation and some tissue damage. Inhalation of the product will cause some irritation to the mucous membranes, but only limited data is available on this particular hazard. Minimize contact with the material.
NONFIRE RELEASE
The first action emergency responders should take at any hazardous-materials incident, after effecting life rescue (if necessary) and any necessary containment actions to keep the contamination from spreading, is to alert the proper environmental authorities.
Mitigation techniques differ based on whether the sodium chlorate is shipped either as the pure solid or as a water solution. Solid sodium chlorate can be cleaned up rather easily if care is exercised and compatible tools are used. The area where the spill has occurred must be examined carefully to determine whether the spilled product has mixed with any organicmaterial. If not, it may be vacuumed up or carefully shoveled into secure containers. In either case, a professional salvage team equipped with compatible tools and equipment should salvage the product, not firefighters.
If there has been some mixing of the sodium chlorate, picking up the product in its solid form might cause a fire from the friction created in moving the material. Instead, watei* might be used to dissolve the product and remove the immediate threat of fire. Before the water is added provisions must be made to contain the resulting solution to keep the contamination from spreading. This action of dissolving the sodium chlorate should be done with the approval of the environmental authorities after they determine that the proposed action will not increase the chance of environmental damage. Remember that the sodium chlorate will be present in the solution, and the solution will soak into the ground.
Whenever there is a threat to human life, however, the incident commander has the authority to order actions that will save the threatened lives, even if the actions in turn threaten the environment. The incident commander has the final word but must be able to justify his actions later.
Before removing the product or adding water to it, you can cover the product with a tarp, a canvas sheet, sheets of plastic, or sheets of other compatible materials to contain it. This will protect the product from being blown around by the wind or being dissolved by rain. If it does rain before the product can be covered, containment dikes should be constructed around the release to keep it from spreading. Make sure you remove the sodium chlorate from the cover before reusing it—the presence of any of the oxidizer on the cover could make it very combustible.
You must prevent both the solid product and its water solutions from entering the sewer system. Sewers almost always contain organic materiat, and the addition of this powerful oxidizer could result in a dangerous fire if an ignition source (or any source of energy) is present. You must notify all sewage treatment facilities.
IDENTIFICATION NUMBERS AND RATINGS
CAS
(Chemical Abstract Services) 7775-09-9
STCC
(Standard Transportation Commodity Code)
4918723
RTECS
(Registry of Toxic Effects of Chemical Substances) F00525000
UN/NA
(United Nations/North America) 1495 solid, 2428 aqueous solution
CHRIS
(Chemical Hazard Response Information System) SDC
DOT
(U.S. Department of Transportation) Oxidizer
NFPA 704 Rating 1 -0-2-OXY
IMO
(International Maritime Organization) 5.1, oxidizing substance-
Keep both the solid and solution forms of sodium chlorate from entering any waterway. Containment ponds built by pushing up dirt, clay, sand, or other materials into dikes and specially dug containment pits can be used to hold the material safely in place. Salvage crews can then pump the solution into secure containers. Sand or clay will absorb any remaining liquid.
SYNONYMS AND TRADE NAMES
Asex
Atlacide
Atratol
B-Herbatox
chlorate of soda
chlorate salt of sodium
Chlorax
chloric acid, sodium salt
De-fol-ate
Desolet
Drexel Defol Drop leaf
Evau-super
Fall
Grain Sorghum Harvest-Aid
Granex O
Harvest-Aid
Klorex
Kusa-Tohru
Kusatol
Ortho C-11 Defoliant and Weed Killer
Oxycil
Rasikal
Shed-a-Leaf
Shed-a-Leaf “L”
soda chlorate
Travex
Tumbleleaf
United Chemical Defoliant No. 1
Val-drop
If solid sodium chlorate enters a waterway it will sink to the bottom and dissolve quickly, depending on the volume of water and the speed with which it is moving. If solid or dissolved sodium chlorate enters a waterway, notify all downstream users of the water immediately. The toxic hazard to fish and other inhabitants of the waterway is very grave, and the product could poison water drinkers downstream. Notify water treatment facilities immediately as well as any industrial users of the water. If the concentration of sodium chlorate in the water is high, cooling water can greatly damage equipment.
The environmental experts will test the water continually to determine when it is safe to use again. They also will test the soil in the vicinity to determine the degree of contamination and the amount of soil that may have to be dug up and removed. All contaminated soil and any sorbents used must be disposed of in accordance with federal, state, and local regulations. Sorbents containing sodiurn chlorate should be treated like pure sodium chlorate.
FIRE SCENARIO
Although sodium chlorate is an inorganic, ionic compound that will not burn, it is a very powerful oxidizing agent and will support the combustion of materials that are most difficult to burn. Any sodium chlorate that is exposed to the heat energy from a fire (or any heat source) will begin to liberate oxygen. This oxygen, of course, will be available to support the fire, and any burning (or smoldering) material that has access to this oxygen will burn faster and hotter. This increased heat output will speed up the release of oxygen, which, in turn, will speed up and increase the heat of the fire even more. This vicious cycle may produce an inferno (depending on the amount of sodium chlorate present) that may be impossible to extinguish with regular firefighting equipment. This phenomenon is similar to flares or fuses used by police to warn of accidents on the highway or flares used by scuba divers. In the proper form, the material will burn underwater because the mixture has its own oxygen supply, intimately mixed with the fuel.
Use water on sodium chlorate that is threatened by fire. If the product is dissolved, the threat of oxygen release is removed. If it is wet but not dissolved, the liberation of oxygen will be delayed as energy is absorbed to evaporate the water. In any case, the runoff water must be contained to prevent the spread of contamination and the eventual evaporation of water, which will leave behind very dangerous, finely divided sodium chlorate.
If trucks, rail cars, and other large containers or stored amounts of sodium chlorate are threatened by fire, consider evacuating people in a onemile radius in case of an explosion. Emergency responders should withdraw at least 2,000 feet, and water should be applied by unmanned appliances.
Evacuation downwind for greater distances may be necessary if the fire reaches large quantities of sodium chlorate. In taking the conservative approach to all chemical incidents, attention must be paid to what some references cite as a possible by-product of the reaction of sodium chlorate under extreme heat: chlorine gas, with all of its attendant hazards (see Fire Engineering, July 1986).
After the fire has been extinguished and the incident has run its course, salvage and/or cleanup procedures may be extremely hazardous. There may be pockets of molten sodium chlorate trapped in the debris and hot organic material may be mixed into it while personnel are moving the product about, reigniting flash fires. More dangerous, however, are any piles or bags of product sensitized by the heat, which might break apart and spill the solid material. Any shock to unburned material mixed with the sodium chlorate might cause explosion. Professional firms using properly educated, trained, and equipped personnel should perform salvage and cleanup, with firefighting forces standing by.
FIRST AID
For inhalation, remove the victim to fresh air. If the victim has stopped breathing or breathing has become difficult, administer artificial respiration (mouth-to-mouth resuscitation may expose the provider of first aid to material in the victim’s mouth or vomit). Seek medical attention immediately.
For eye contact, immediate medical attention is mandatory. Until it is provided, flush the eyes with water for at least 15 minutes, periodically lifting the lids.
For skin contact, remove all contaminated clothing and wash all contacted areas with large amounts of water. Immediate medical attention is necessary.
For ingestion, if the victim is conscious and not convulsing, induce vomiting. Never try to force an unconscious person to vomit. Call for immediate medical attention. Keep the victim is warm and comfortable.
PROTECTIVE CLOTHING AND EQUIPMENT
Select protective clothing and equipment that prevent contact of the material with the eyes, skin, and respiratory system. Rubber boots, gloves, and aprons may offer protection, and turnout gear should be similarly resistant to this oxidizing agent. Safety goggles and splashproof goggles for solutions and face masks impervious to sodium chlorate will protect the face and eyes. Do not use leather gloves or shoes.
Do not use greases, oils, or protective creams or lotions that might come into contact with sodium chlorate. An immediate, violent reaction may occur.
Wear positive-pressure, self-contained breathing apparatus when dusts and mist are present.
