Bushfire Bunkers #2

We are actively considering a bunker as a last resort option for our home, but I remain worried about them. Tonight I came accross the following from CSIRO's page 'Q&A: Victorian bushfires':

What research has CSIRO done on fire bunkers?

CSIRO is not currently conducting research into bushfire bunkers or shelters. Previous research by the Department of Defence indicated that underground bunkers may not be safe in bushfires due to the accumulation of toxic gases coming from a bushfire itself.

....

As well as the technical issues, there are a range of other considerations including:

• decision making processes and education around when to retreat to the bunker
• when to close off a bunker
• how long to remain in the bunker
• how to determine when it is safe to exit the bunker.

...

It is a worry.