I'd go for powder it's far safer than CO2 particularly in a confined space it can kill.

Sure powder is messier but a lot safer. It will knock down the fire far more effectively, it's what they use at race tracks for that very reason.

2009 4/4 Henrietta
1999 Indigo Blue +8
2009 4/4 Sport Green prev
1993 Connaught Green +8 prev