Chemicals known as persistent organic pollutants, or POPs, include pesticides such as DDT, industrial chemicals such as polychlorinated biphenyls (PCBs), and dioxins and furans – by-products of industrial processes or waste incineration. As their name implies, POPs stay in the environment for years, can be transported over great distances by wind and water currents – accumulating especially in the polar regions – and enter the food chain, posing a hazard to human and planetary health. DDT became the most famous POP due to Rachel Carson’s 1962 book Silent Spring, which led to its withdrawal in the USA. Still used to fight malaria, DDT causes abnormalities in wildlife and is found in human breast milk. The international community is working to eliminate POPs under the 2001 Stockholm Convention on Persistent Organic Pollutants. The treaty has eliminated or restricted the use of 12 specific POPs, but continues to research other chemicals, adding new ones to its banned list as necessary.