Some complexities and limitations of using carcass residue data to determine secondary hazard to nontarget species are discussed. The roles of chemical and toxicological properties of the rodenticide such as metabolism, excretion, organs of retention, site of absorption and latent period in secondary hazard are reviewed and examples given. The possible effects of bait composition and application methods, the behavioral response of the nontarget species, and local environmental factors upon secondary hazard are outlined
