After receiving much feedback on the choice of water to extinguish this chimney fire, here's the rationale: we've made this same residence repeatedly for chimney fires due to poor maintenance. This time we had concern that the flue had already been compromised. Extinguishment from below had already been attempted without success. Water fog was used, the chimney cleaned by TFD using both a trash hook and a commercial chimney sweep, and the homeowner was advised NOT to use the chimney further until inspected and repaired by a general contractor.