OK, peeing in a swimming pool is gross, but if it’s insufficiently gross dissuade potential pee-ers, here’s another thing to think about. Researchers at Purdue University have found that the uric acid in urine interacts with chlorine (in pools) in surprising ways, and can create hazardous “volatile disinfection byproducts,” including cyanogen chloride (CNCl) and trichloramine (NCl3). What are they? Cyanogen chloride is a toxic compound that affects many organs, including the lungs, heart and central nervous system by inhalation. Trichloramine has been associated with acute lung injury in accidental, occupational or recreational exposures to chlorine-based disinfectants. The Purdue findings were not a complete surprise. Researchers had known for years that certain airborne contaminants are created when chlorine reacts with sweat and urine in indoor swimming pools, but new findings show that uric acid from urine is definitely “an efficient precursor to the formation of CNCl and NCl3.