A group of chemicals known as the “dirty dozen” were the original group of chemicals banned by the Stockholm Convention on Persistent Organic Pollutants (POPs). All of these chemicals possess toxic properties, resist degradation, and are transported across international boundaries via air, water, and migratory species. The Convention went into effect in 2004. Since then, other chemical compounds have been added or are being considered for inclusion on the list since the original 12. Health effects of these compounds include disruption of the endocrine system, cancer, and adverse effects in the developmental processes of organisms.