The Future of Environmental and Climate Law

Environmental law was largely built around known, measurable pollutants from identifiable industrial sources. The regulatory challenge of the 21st century increasingly involves emerging contaminants — pollutants that are widespread in the environment and demonstrably harmful, but where the science, source identification, and regulatory frameworks are still evolving. Per- and polyfluoroalkyl substances (PFAS) and microplastics are two defining examples.

PFAS are a class of thousands of synthetic fluorinated chemicals used since the 1940s in a vast range of products: non-stick cookware, waterproof clothing, food packaging, firefighting foam (AFFF), and countless industrial applications. PFAS are characterized by extraordinary chemical stability — the carbon-fluorine bond is one of the strongest in chemistry — leading to their common name 'forever chemicals.' They do not break down in the environment or in the human body, accumulating in blood, organs, and tissues. Health research has linked PFAS exposure to thyroid disease, immune dysfunction, kidney and testicular cancer, and developmental effects in children. Studies find PFAS in the blood of virtually all Americans and in environments worldwide, including remote Arctic regions and the deep ocean.

The EPA issued its first-ever PFAS National Primary Drinking Water Regulations in April 2024, setting Maximum Contaminant Levels (MCLs) for six PFAS compounds — the first new MCLs under the Safe Drinking Water Act in more than 25 years. The regulations require public water systems to monitor for PFAS and reduce concentrations to specified levels. The compliance and remediation costs are enormous: EPA estimates 66,000–106,000 public water systems will require treatment, at costs of $1.5–3.1 billion annually.

Microplastics regulation presents different challenges. Unlike PFAS (which come from identifiable chemical manufacturers), microplastics arise from the breakdown of macro-plastic products — a diffuse, global source. Their ubiquity (found in human blood, lung tissue, placentas, deep-sea sediment, and Antarctic snow) raises concerns, and emerging research is beginning to identify potential health effects, but the dose-response relationships and specific health mechanisms are still being established. Regulatory approaches range from restrictions on single-use plastics and extended producer responsibility schemes to microplastics monitoring requirements in water — but comprehensive regulatory frameworks remain nascent.