The detection and identification of war gases : notes for the use of gas identification officers.

Date:
1943
Catalogue details

Licence: Public Domain Mark

Credit: The detection and identification of war gases : notes for the use of gas identification officers. Source: Wellcome Collection.

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    and other bombs. It is, nevertheless, prudent to suspect all unusual clouds and smokes as possibly containing gas, and take steps accordingly. In general, such non-persistent gases and smokes will have dissipated to a greater or lesser extent before the Gas Identification Officer arrives, leaving possibly a slight odour behind, and possibly also a certain amount of visual evidence in the form of rotted clothing and bleached vegetation, or corroded metals, particularly copper and copper alloys (notably with the lung irritants in damp weather). “The size of the crater made by the bombs may also point to the use of gas, the cratering produced by H.E. bombs being usually con- siderably deeper and more extensive than that from gas bombs. ‘ With persistent gases, on the other hand, and mustard gas in particular, smell may or may not afford a reliable indication, according to the prevailing circumstances, but contamination of ground and/or buildings with the liquid gas will normally occur, and so afford visual evidence of the presence of the gas. The possibility must not be overlooked, however, that persistent gases might be used in bombs with high bursting charges, which would simulate H.E. bombs in noise of burst and size of crater and would disperse the greater portion of their war gas charging in the form of a highly concentrated but non-persistent cloud of-droplets and vapour. : Contamination by crude mustard gas, of black colour, is naturally somewhat easier to detect visually than contamination with the purer pale yellow product, though apart from colour the “‘ stains ’’ produced by both have much the same appearance. On dry porous surfaces, brickwork, cement, stonework and so on, the liquid is rapidly absorbed, leaving a dark oily stain. On dry roads and dry earth it similarly appears as a wet oily patch, whilst on wet surfaces it spreads and gives a slight iridescent effect, similar to that of paraffin on such surfaces. It rapidly penetrates bare wood, especially along the grain, but remains as liquid drops and splashes on painted surfaces for a considerable time, though it tends eventually to soften and dissolve in the paint film. It does not penetrate into metals, glazed tiles, and similar impermeable materials, and also remains in droplet form on green foliage . and grass for some time, though it eventually penetrates into and damages living vegetation. In water the bulk sinks to the bottom, but a thin, some- what iridescent film usually remains on the surface for a time. These remarks apply, for the most part, to the zone of relatively gross contamination in the immediate vicinity of a bomb crater. The lighter con- tamination further away, and also the contamination resulting from aircraft spray, takes the form of very small (sometimes pin-point) droplets, and is, naturally, less apparent, and accordingly more difficult to detect visually, (cf. Section (13) (b) below). In the form of a mist, these minute droplets may drift for considerable distances downwind from the point of release. A word of warning is necessary in connection with the visual detection of blister gas contamination; the persistent lachrymators are dark-coloured oils similar in appearance to crude blister gases, and care must be taken not to confuse the two types—a relatively easy matter if the Gas Identification Officer is wearing a respirator, and omits to make periodic smelling tests. (c) Other Senses.—_The other senses are not of particular value from the gas detection point of view, but the circumstance that gas projectiles normally burst with much less violence than H.E., and do not flame like Incendiary, is worth bearing in mind. It may also be mentioned that the hissing noise of gas escaping from cylinders occasionally afforded a valuable warning during the war of 1914-18 though this method of release is not, of course, likely to be encountered in aerial attack. (d) Phystological Effects——The physiological action of war gases affords a valuable warning indication in the case of those which exert an immediate irritation on some part of the body. Lachrymators, for example, are readily recognised by their immediate irritant effect on the eyes even in very low concentrations (I in 20 to 30 million). In the same way, the nose irritants
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