"Furthermore, most modern tear gas bombs are non-incendiary in nature."
You're right. The vast majority of teargas bombs are either the pressuized liquid variety or the bursting powder container variety. Neither of these can start fires, period. The FBI and BATF, however, still stock the military incendary CS canisters, and use them to burn out suspects, especially when an officer is killed in the initial assault. Federal guidelines prohibit the use of these incendary CS canisters indoors, but as we found out in Waco, such federal guidelines are meaningless when federal officers in the field want the suspect dead. Federal SWAT teams are, IMHO, vigilante murders with badges. They've proved that to be true repeatedly.