Chapter 3 explores the willingness of some state courts in the early 21st century to consider and approve plaintiffs assertion of public nuisance claims in developing mass tort litigation. This chapter involves a case study of the lead paint litigation, describing high incidences of childhood lead paint poisoning in older buildings as the basis for the lead paint lawsuits. These lawsuits attempted to hold the manufacturers and sellers of lead paint liable on a theory that the defendants created and maintained a public nuisance relating to lead paint. Many courts initially declined to allow plaintiffs to assert public nuisance claims in the lead paint litigation, based on various defenses sounding in lack of proximate caustaion, remoteness, and failure to satify the elements of a public nuisance claim. However, courts in Wisconsin and California subsequently accepted the plaintiffs pleading of a lead paint public nuisance claim, based on the defendants advertising and promotion of their products. These successful lead paint cases illustrated a conceptual breakthrough in judicial receptivity to communitywide public nusiance claims. However, other courts continued to reject lead paint public nuisance claims, illustrating the unsettled nature of public nuisance law.