This has turned into a religious war in the building.[...]Our goal is to gather as much factual data as we can find, present to the whole building, and then let them vote.

If it's turned into a religious war, don't waste your time any more -- the anti-grill people will vote no regardless of the safety considerations. You're probably more likely to have problems with earthquakes in SF, than you are with grills.

the anti-grill folks are doing everything possible to prove their case against the safety of propane tanks.

Word any regulations carefully enough to not say anything about charcoal grills.