Under the legal theories of negligence, it is sufficient cause for liability that the owner of the building in which the fire occurred left the building vacant and unsealed against intruders, thus substantially increasing the risk of a fire. With regard to proximate cause, an element that must be proven in negligence, the primary issue is whether or not an intruder's firesetting is a 'superceding cause.' If so, the building owner would be relieved of liability for the fire. The courts, however, are not likely to hold that the intruder's actions are a superceding cause, since they are a foreseeable consequence of the owner's negligence in leaving the building unsecured. New York's 'one-building rule' limits the liability of the fired-building owner to damages caused to property directly adjacent to the fired building. The rationale underlying this rule is outdated, and the prospects for overturning it are good. Although a successful suit against a building owner will not fully compensate for the disruption and damage caused by a fire, significant monetary awards will encourage building owners to provide proper security for their vacant buildings in the future. Ninety-five footnotes are provided. (Author summary modified)