We well know that gas was used on and near the front lines by both sides but was it used at longer distance? By 1917/18 was it being used in shells which could be fired some miles behind the lines at, for example, our guns or rail stations?
Mike

One of the problems with a gas attack was laying down a thick enough concentration fast enough which meant getting shells in faster than the gas could disperse. This is why the Livens proector (where a lot of projectiles could be fired en masse) was such a success but the slow loading 6 inch Newton was not used for gas. Long range guns were not quick loaders. If nothing else the men at the target would have a reasonable chance of getting their masks on before any concentration was built up. Gas would not destroy an installation - it was anti people weapon (much like a neutron bomb). If you want to knock out a railway junction fire HE at it.

Hello,

A gun detachment with their gas masks on are much less efficient than one with their gas masks off. Gas, delivered by shells, would be part of a fire plan for an offensive, with, for example, the object of disrupting the enemy's counter battery fire.

Old Tom

Gas shells where used in counter battery work. In 1917 some of the batteries, 1 in 4 of the shells fired in counter battery work where gas shells. Do a search on some of Robert Dunlop posts.

Yes but not "miles behind the lines" as the original post asked.. A 1920 text book on gas warfare states that to neutralise a battery probably required 4 or more hours of fire with a persistant gas (the gas masks start to fail after this time). If what you want to do is to merely hamper the crews by forcing them to work with masks on one of the tear gases is recommended as it requires much less volume of gas to cover a wide area even if it is non lethal.
To make a village or railway station unuseable for a while required the use of mustard gas in some volumes as the stuff lingers. Again not miles behind the lines but where there could be enough fire concentrated to saturate the area. It recommends not using this tactic if you expect your troops to take this objective!

Interestingly it is suggested that the Germans were unable to manufacture sufficient volumes of mustard gas to make much use of this tactic.

Many thanks
Mike