The poisonous gases which occur in mines, and which are formed in large quantities when high explosive goes off in an enclosed space, e.g., from a direct hit in a shelter, or on the explosion of a charge in a mine, are not protected against by the ordinary anti-gas appliances. The chief of these gases is carbon monoxide. Protection against such gases will not be considered in these notes.

Officers are held responsible that all the anti-gas appliances for protecting their men are maintained in perfect condition, and that all ranks under their command are thoroughly trained in the use of these appliances and in all other measures which may affect their safety against gas.

Summary of Protective Measures:

  1. Provision to each man of individual protective devices.
  2. Arrangement for the inspection of those appliances and training in their use and instruction in all other measures of gas defense.
  3. Provision of protected and gas-proof shelters.
  4. Weather observations to determine periods when the conditions are favorable to a hostile gas attack.
  5. Arrangement of signals and messages; for immediate warning of a gas attack.
  6. Provision of appliances for clearing gas from trenches and shelters.

C. Protection of Shelters:

(1) Methods Of Protection:

Protection of dugouts, cellars, buildings, etc., is given if all entrances are closed by well-fitting doors or by blankets sprayed with hypo. solution. Practically no gas passes through a wet blanket, and the protection depends on getting a good joint at the sides and bottom of a doorway, so as to stop all draughts. This can be effected by letting the blanket rest on battens, fixed with a slight slope, against the door frame. The blanket should overlap the outer sides and a fold should lie on the ground at the bottom. A pole is fastened to the blanket, which allows the latter to be rolled up on the frame and causes it to fall evenly.

Wherever possible, particularly where there is likely to be movement in and out of the shelter, two blankets fitted in this way but sloping in opposite directions should be provided. There should be an interval of at least three feet between the two frames, and the larger this vestibule is made the more efficient is the dugout.

When not in use, the blankets should be rolled up and held so that they can be readily released, and should be sprayed occasionally with water or a little Vermorel sprayer solution.

If the blankets became stiff from a deposit of chemicals, they should be sprayed with water.