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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    Extraction methods may be necessary in dealing with samples contaminated with persistent lachrymators, but in such cases alcohol is usually preferable to ether as a solvent, as the subsequent hydrolysis is effected in that medium. In this connection, also, it should be borne in mind that solvent extracts of samples contaminated with mustard gas may contain thiodiglycol, its innocuous hydrolysis product. The latter gives the same iodoplatinate reaction as unhydrolysed mustard gas, and it is therefore necessary to employ the less sensitive but more specific B-naphthol or gold chloride tests to enable a differentiation to be made between the two. This difficulty does not arise with the air-flow method, since thiodiglycol is virtually non-volatile under ordinary conditions. (¢d) Examination of contaminated foodstuffs and water._The examination of foodstuffs and water suspected of having been contaminated with war gases will not be the responsibility of G.I.O.’s, though they may be called upon to advise and report when such contamination has occurred. So far as concerns foodstuffs, where these have been exposed to vapour only, it will, in many cases, be possible to render them safe for consumption, though possibly still somewhat unpalatable, by airing for a day or so: where, however, liquid contamination has occurred, removal and destruction of at least the outer layers of the contaminated material will be necessary. In either case, of course, the treatment would have to be continued until the materials gave completely negative results on subsequent chemical and physiological examination. As regards the contamination of water supplies by war gases, filtration through an ordinary filter-bed will remove all undissolved gas and insoluble products of-hydrolysis, and the amount of dissolved gas and/or toxic decompo- sition products present in the filtered water will, in general, only be significant in the case of small reservoirs which have been heavily contaminated with liquid gas. Where mustard gas is the contaminant, any gas dissolved in the filtered water will be slowly destroyed by hydrolysis, and after standing for 24 hours (or on a small scale boiling for 15 minutes) the water, though possibly unpalatable, can be safely used for drinking purposes. With lewisite and other arsenical gases, however, special chemical treatment will be necessary to remove dissolved toxic products from the water. Slow filtration through charcoal is, in general, effective for removing dissolved war gases from water, but does not satisfactorily remove the oxidation products of arsenical war gases and is quite ineffective, for the removal of dissolved inorganic arsenical compounds. (e) Testing for freedom from contamination.—The question of testing areas and objects for freedom from gas will normally only arise in the case of con- tamination by vesicants, and mustard gas in particular, since it will usually be evident from subjective indications whether other types of ie are still _ present in significant quantities. Areas which have been contaminated with mustard gas may be considered as safe for traversing if the surface layers show no sign of the presence of liquid gas when tested in the usual way by means of detector paper (Sect. (13) (b)). Where, however, occupation of an area downwind of contamination, or of a decontaminated area, is concerned, it is necessary to estimate chemically the average concentration of mustard gas: vapour in the atmosphere over the area in question so as to enable the allowable time of exposure to be assessed. Details of the method of estimating mustard gas vapour by the SD test, and some notes on the interpretation of the results obtained, are given in Appendix I. The information afforded by the SD test used in this way relates, of course, solely to the vapour danger arising from ordinary occupation of the area in question, and does not exclude the possibility of skin effects resulting from
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