Chemical contaminants have been shown to cause a variety of harmful health and reproductive effects to several bird species, including reducing the likelihood of eggs successfully hatching. Although many contaminants have been banned for decades, these chemicals do not break down readily in the environment and persist in aquatic food chains, continuing to impact birds and other wildlife. New contaminants are introduced to the environment as well. The impacts of these contaminants on loons are not well understood but are likely similar to other birds; and, as a fish-eating bird at the top of aquatic food chains, loons are important indicators of levels of these contaminants in the environment. LPC tests unhatched loon eggs from failed nests for a variety of contaminants, including PBDEs (flame retardants), PFAS contaminants (stain guards, firefighting foam), PCBs (industrial insulating/cooling agents), DDT and chlordane (pesticides), dioxins and furans (byproducts of industrial processes), and trace metals, including mercury.