It would need to be an appropriate fire extinguisher - LiPo fires burn without oxygen - I had one go up 10 seconds after being kicked out of my kitchen. 4 foot flames for about a minute was very impressive. It was my own fault though - I wasn't using a balance charger, I didn't use a LiPo sack and I left it unattended... my missus went berserk (funnily enough).
Saying all that - the batteries in this thread are all Li-Ion packs - a lot safer...