 Studies at the atoll on the impact of PCB contamination in reef damselfish ("Abudefduf sordidus") demonstrated that embryonic abnormalities could be used as a metric for comparing contaminated and uncontaminated areas.Some PCB contamination in the lagoon was traced to Coast Guard disposal practices of PCB-laden electrical transformers.In 1962, plutonium pollution following three failed nuclear missile launches was heaviest near the destroyed launch emplacement, in the lagoon offshore of the launch pad, and near Sand Island.