Chlorine Chemistry Council v. EPA 206 F.3d 1286 (D.C. Cir. 2000) Pursuant to the Safe Drinking Water Act (SDWA), EPA had to set a "maximum contaminant level goal (MCLG). EPA had set MCLGs based on the data they had available at the time.  Because no safe threshold for chloroform had been established, EPA conservatively set the MCLG at 0. Years later, EPA re-considered the risks from chloroform when studies shows that there was a threshold level for chloroform contamination, and under that level there was no risk.  However, EPA decided to keep the MCLG for chloroform at 0. EPA argued that, although they had new evidence showing that small amounts of chloroform weren't a health hazard, they wanted to wait until they was super-absolutely sure before changing the MCLG. The Chlorine Chemistry Council and other industry groups sued, arguing that EPA violated its statutory mandate to use the best available evidence when implementing the provisions of SDWA. The Appellate Court found for the Council. The Appellate Court found that EPA cannot reject the best available evidence simply because of the possibility of contradiction in the future by evidence unavailable at the time of action. It's always going to be possible that new evidence will arise in the future. The Court noted that SWDA mandates that EPA use "the best available, peer-reviewed science and supporting studies conducted in accordance with sound and objective scientific practices."