4.2-inch chemical mortar

[Doug Knight]

Hi

The Canadian War Museum has two 4.2-inch Chemical Mortars M1 or M2. They both have Canadian Forces Registration Numbers - CFR xxxxx.
Does anyone know when the CF used them? I know the British 4.2-inch mortars were used by the MG regiments in WW2 and the RCA light batteries used the US 4.2-inch M30 after the war.

Doug