[Oorang]

That's interesting, thanks Velveeta. A post from that threat states:
From KHOU, our local CBS affiliate, some more info is offered: “The canister vanished from the second floor of the plant in the 16,700 block of Glenagle Drive North. It is 150 pounds of stainless steel and is marked chlorine gas.”
8 posted on 07/03/2007 8:26:35 PM PDT by Weight of Glory

To me that indicates it is not a drug addict looking for scrap metal to sell. Why hassle with lugging 150 pounds from the second floor when there are probably easier pickings for scrap.

[Velveeta]

Chlorine gas is deadly. Perhaps it was just ‘youths’ breaking in, just for grins and giggles.