Given limited storage space, kerosene probably gives you the most BTUs for the least hazard.

But you're right about the ventilation issues. At least crack the windows open and have a good CO detector.

Seems you should bring the issue up with your neighbours and the association. If everybody faces the same risk, perhaps some accommodations can be made. Freezing pipes etc. are everybody's concern.

If you're on natural gas for heating, be aware that the gas usually keeps flowing even when the power is off. (These guys are mostly independently powered -- they use jet engines to drive their compressors, running of course on natural gas.) Consider a gas fireplace that doesn't require line voltage, or get a generator to run your furnace / fridge / freezer.

My 2¢.