PFBS is a man-made chemical used in manufacturing and firefighting foams. It persists in the environment and accumulates in the body, potentially causing liver and thyroid problems.

PFBS (Perfluorobutane sulfonic acid) is part of the PFAS family of chemicals. It was introduced as a replacement for PFOS, which was phased out due to health concerns. PFBS is used in various industrial processes and consumer products, including water-resistant coatings and firefighting foams. It enters water systems through industrial discharges, landfill leachate, and contaminated soil. PFBS is highly persistent in the environment and can travel long distances in water. It's typically measured in parts per trillion (ppt) using specialized laboratory techniques.