Apparently called in by a passer by visiting from out of town, from way down south, and had never seen a dryer vent put off steam in the winter time in the northeast US. Luckily it was just that. The building in which it was reported is a very large and old(at least 100 years old)home converted into 3 apartments, with many additions, remodeling jobs, paper thin walls, drop ceilings, balloon construction, etc... It would have been one hell of a mess had it been an actual structure fire.