Objective-To describe legal theories that non-smoking residents of multiple occupancy buildings may employ when affected by environmental tobacco smoke (ETS) from neighbouring units. Design-Legal research was conducted in several US states. Research was performed among statutes and regulations. State health regulations were examined as well as common law claims of nuisance, warranties of habitability, and the right of quiet enjoyment. Results-Through the use of state regulations, such as a sanitary code, several states provide general language for protecting the health multi-unit buildings. supports more traditional claims or nuisance, warranties of habitability, and the right of quiet enjoyment. Conclusions-The use of state regulations has the potential to provide an effective, existing vehicle for resolution of ETS incursion problems. The general health protection language of the regulations, in conjunction with the latest evidence of the harmful effects of ETS, gives state agencies authority to regulate environmental tobacco smoke incursions among apartments in multi-unit dwellings. Where state regulations are not available, other common law legal remedies may be available.