ST. LOUIS - A Missouri federal judge on March 31 certified a class of West Alton, Mo., residents within a quarter mile of a 1960s pipeline leak but said the plaintiffs had failed to show actual exposure to benzene or lead necessary to justify medical monitoring (Bruce Smith, et al. v. ConocoPhillips Pipe Line Company, No. 4:11-CV-2040, E.D. Mo., Eastern Div.; 2014 U.S. Dist. LEXIS 43172).