Originally Posted by
Endemerrin
Actually, I think it's mentioned that those belong to the Garlond Ironworks. Cid talked about their Ceruleum mining operations during one of the Immortal Flames GC quests. Some Maelstrom pirates were trying to steal Ceruleum, and he warned them to not be so reckless with the crates because it's an incredibly volatile substance.
Think he said something along the lines of a single explosion being enough to set off a chain reaction that would blow up most of Northern Thanalan.