SODIUM CHLORATE

Hawera Star, Volume LIII, 17 June 1933, Page 7

SODIUM CHLORATE

PRECAUTIONS IN HANDLING PROTECTION OF THE WORKER. DEPARTMENTAL B ULLETiN. Several serious accidents, including at least two deaths, have been caused by the clothing of farm workers bursting into flames when dry and impregnated with sodium chlorate from the solution used in spraying ragwort. Workers with sodium chlorate should read carefully the instructions for using this material, which when carelessly handled is capable of inflicting severe bums and endangering both life and property (states a Departmental bulletin).

The method most generally adoptoi. in New Zealand for .exterminating weeds by means of sodium chlorate i, that of spraying the chlorate dissolvea in water on to the plants. In doing this the solution is apt to become spilt oi splayed on to tbe \vorncr s clothing, impregnating the cloth with chlorate. Jhe water l apiaiy evaporates, leaving the chlorate uistributed with the fibres oi the cloth and in the closest contact. The dry clothing is habit; to burst into flames with great rapidity as soon as a spark, a biow, oi fiiction is applied at any one spot. Heating the clothing by coming too near a fire and without actual contact with a spark or flame, or heating by friction or by concussion from a Sudden blow, may also cause a garment to take fire or even to explode. In iaet, the person with clothing contaminated by chlorate resembles a human match of which the chlorated spot is the match-head. The danger that saturated clothing when dry may become an explosive mixture also increases the risk of fire, while contributing an added menace from the shock of explosion or detonation.

The difficulties of transporting sodium chlorate are increased by the fact that it cannot be contained in combustible bagging, casks or barrels witfaout clanger. It should be canned packed in tinned iron receptacles only, within iron containers, on the railway, since a leakage on to a wooden truck floor would be dangerous and difficult to entirely remedy. When the original iron drum is opened, only metal, porce. lain, glass, or enamelled vessels should be used for holding the chlorate or the solution. Zinc (galvanised) vessels or zinc-lined vessels are unsuitable. 1 All containers which have held ehlor-j ate should, when empty, be thoroughly washed out with water * ! Workers using chlorate, should wear* as little clothing as possible, and this should be water-proofed—oilskins, rubber leggings and gum boots—ail ofi which can be well and easily rinsed' iii running water. ’ If any cheap combustible material, such as bags, casks, or chaff, becomes | contaminated by chlorate, the best i method of disposal is to burn' the I Contaminated articles at once, otlier-j w ise they w ill always be a source of j danger. If ordinary clothing becomes saturated with sodium chlorate solution it is not sufficient merely to steep the garments in water or to w*ash them in the ordinary way, as experience has shown that this may merely' distribute the chlorate more widely and increase the danger of fire. The clothing must be thoroughly rinsed in a succession of waters, best accomplished by immersion in running water in all cases, but especially necessary with thick woollen clothing.

PACKING AND TRANSPORT. Sodium chlorate conies on to the market packed in iron drums. The substance consists of- small white crystals which resemble those of common salt (sodium chloride). The names of these two compounds arc similar, but their properties are very different, and, of course, they are used for entirely different purposes. Even when unmixed with inflammable matters sodium chlorate is liable to explode by percussion and triction in the same way as chlorate of potash. Hence sodium chlorate should be. handled with care, and not dropped on to a concrete, tiled, or iron floor, nor subjected to any violent blow. Sodium chlorate is very soluble, in. -water, a, fact-which must be remembered in dealing with mixtures of lime and chlorate if stored or used in a way that rain can touch the mixture. The shower will dissolve the. chlorate out very readily, and when this rain water carries the chlorate into contact with combustible matters danger is created?

Some persons have taken advantage of the fact that mixtures of sodium chlorate and combustible substances are highly explosive to utilise such mixtures as explosives .on the farm, but to make such an explosive without a license is contrary to law. The G'hief Inspector of Explosives has intimated his intention to prosecute in any such case brought under his notice. Several parcels of chlorate ha ve been received through the post. This is also contrary to law, and under section 107 of the Post and Telegraph Act, 1928, such an offence is punishable by imprisonment for a term not exceeding two years or by a fine not exceeding £SO, or both.

In future sodium chlorate will not (except as mentioned below) be accepted for conveyance by rail unless, it is contained in the original iron drum in which it was imported. Small consignments of sodium chlorate —that is, in quantities of less than one drum and not contained in tlie original drum—will be accepted for conveyance if securely packed in a tinned iron receptacle; such consignments must, however, be forwarded in one .of tbe special containers provided for the' carriage of explosives, etc. If a receptacle containing sodium chlorate is damaged and the contents released, the utmost care must be exercised to ensure that all the chlorate is gathered up. Water must not be used to remove chlorate in such cases, as the resultant solution, when dried, is highly inflammable and explosive