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."