Greek fire factory!
Think about it- We still don't know how it was made. This leaves tons of room to play- have scientists rediscovered the recipe to use in times of war? Or are you depicting the factory of ancient times? I've also heard that small factories were set up on ships for making it. Greek fire was used by many cultures, and you can let your architecture speak as to which you're representing. This has the added bonus of most likely being an interior scene.