Stuart William Krasner (Born 1949), was the Principal Environmental Specialist (retired) with the Metropolitan Water District of Southern California, at the Water Quality Laboratory located in La Verne, California. In his 41 years with Metropolitan, he made revolutionary changes in the field's understanding of how disinfection by-products occur, are formed and how they can be controlled in drinking water. His research contributions include the study of emerging DBPs including those associated with chlorine, chloramines, ozone, chlorine dioxide and bromide/iodide-containing waters. He made groundbreaking advances in understanding the watershed sources of pharmaceuticals and personal care products (PPCPs) and wastewater impacts on drinking-water supplies. For DBPs and PPCPs, he developed analytical methods and occurrence data and he provided technical expertise for the development of regulations for these drinking water contaminants. In the early 1990s, Krasner developed the 3x3 matrix illustrating removal of total organic carbon from drinking water as a function of water alkalinity and initial total organic carbon concentration. The matrix was revised by him and included in the USEPA Stage 1 D/DBP regulation as the enhanced coagulation requirement. Every water utility in the U.S. that is subject to this regulation is required to meet total organic carbon removal requirements along with their exceptions.