Mustard .... 75mm rounds.
Just HD, not the really nasty stuff [HD and DM] that got you puking in your mask until it filled up and you pulled it off.
Ever see A HD Chemical Mine? Just a one-gallon rectangular paint can, with a couple of heavy twistable wires soldered onto the side to attach a quarter-pound demo block to atomize and disperse it. Not real effectively, but useful for waterhole denial in arid places like Afghanistan or Iraq.
Filling was to be done by the Chemical Warfare Corps troopies, wearing full protective gear, then emplaced by the using units after decontamination of the outsides of the cans with DS2.
I used to have hundreds of the things that had never been filled, handy as hell if you had access to paint in 6-gallon plastic buckets and wanted it in something a bit more managable. Four snips with a sidecutter, and the demo charge retaining wires were gone, which made stacking the things a bit easier. I gave $ .08 each for them in thousand-can lots, as I recall.
Yep just sulfur no arsine oil......too many experimental items to come out of the old heavy rubber Huntsville lingerie ......
We used basics of det cord and fuel after venting with a Mk 2 shape. Even got too experiment with solvated electron technology a wee bit........not real good stuff for the CW crap. Made uxo a non hazardous waste though. Real good for restoration efforts !