The U.S. Chemical Safety and Hazard Investigation Board (CSB) previously said the incident began with a chemical reaction involving trichloroisocyanuric acid (TCCA), sodium dichloroisocyanurate ...

29 sent plumes of chlorine into the air. Last year, the federal agency published an investigation titled, “Trichloroisocyanuric Acid Reaction, Decomposition, and Toxic Gas Release at Bio-Lab ...