As a firefighter and one of those fellows that might inspect you. I would agree with Scotty, a 5lbs ABC all purpose fire extinguisher is your best bet, and easiest to find. Another one would be a class A pressurized water extinguisher. They can be filled with water and pressuized with any air compressor. Those are the big silver ones you see hanging in schools. They are hard to find, and they can be expensive.
KCBS Member - Lang Model 60 - Brinkman Bullet - firstname.lastname@example.org