Steven Thomas (plaintiff) suffered cognitive defects from ingesting white lead carbonate contained in lead paint that was used in the houses where Thomas lived as a child. Thomas, who was born in 1990, lived in homes that were built between 1900 and 1905. Due to the passage of time, the large number of pigment manufacturers that used lead-based paint, the generic nature of lead paint, and the lack of records available for Thomas’s childhood homes, Thomas was unable to identify the particular manufacturer of the pigment that caused Thomas’s lead poisoning. Thomas brought a products-liability suit based on negligence and strict liability against several pigment manufacturers (defendants) of white lead carbonate. The defendants knew that white lead carbonate was harmful, but continued to manufacture and market lead-based pigments. In the lawsuit, Thomas sought to extend to white lead carbonate the theory of market-share liability (or, risk contribution) that was originally adopted and made applicable to the drug diethylstilbestrol (DES). Thomas presented evidence that lead poisoning affected countless individuals, many of whom were children. The defendants claimed, among other things, that white lead carbonate was not a fungible good, as required for risk contribution, because various manufacturers used different chemical formulas to create the compound. The trial court refused to extend the doctrine of risk contribution beyond DES and granted summary judgment to the defendants. The court of appeals affirmed. Thomas appealed.