I've been watching this video on youtube (the first minute and a half cover the stuff that pertains to my question) and it looks like when refining titanium you have a canister of molten magnesium. What happens to this magnesium when the plant isn't functioning? How is the magnesium stored? I read about Mg that it's very flammable but not so much when it's in large chunks. If they are going to melt it, though, wouldn't they want small chunks? Can I expose the Mg stored for use there to the air and cause a big white light and a big fire?

They also introduce chlorine gas into one step of the process. Do they store it in gas tanks, I presume? If so, would damaging a tank flood the area with chlorine gas? Are gas masks sufficient to allow a person to function in that situation?

If I understand correctly, they don't just have canisters of titanium tetrachlorine sitting around. It's something produced when the process of refinement is underway, right? So no amount of grenades or bombing is going to create a situation where the titanium tetrachlorine is exposed to air or water...?

They also use argon in the process of refinement. This made me think of two possibilities. 1) Maybe the Mg gets lit up somehow and someone has the bright idea to put that fire out by opening up a tank (?) of argon. 2) As argon is denser than oxygen this could very well create a dangerous situation if the argon went into an enclosed space, so people might asphyxiate.

Please let me know if anything I've said here makes sense or is completely wrong-headed. I want my heroes to have to deal with a significantly challenging situation as they try to steal the titanium so any suggestions are very much appreciated.