PFAS (per- and polyfluoroalkyl substances) are a group of synthetic chemicals that have been widely used in various consumer products and industrial processes due to their unique properties, such as resistance to heat, water, and oil. However, these 'forever chemicals' do not readily break down in the environment and have been found to accumulate in the human body, leading to growing concerns about their potential health and environmental impacts.

The podcast episodes discuss the challenges posed by PFAS, including efforts to remove them from drinking water, the difficulties in disposing of PFAS-containing waste, and the legal actions taken against PFAS manufacturers for allegedly failing to disclose the known risks of these chemicals.