On May 1, 2012, US EPA announced that it had finalized its third list of 'unregulated contaminants' for future monitoring by drinking water providers.  We reported on release of the draft list of 30 substances, and included a listing of the originally-proposed 28 chemicals and 2 viruses, on January 12, 2011.  The final rule identifies mostly the same subtances for monitoring, such as previously-unregulated perfluorochemicals, PFOA and PFOS, except that EPA has deleted n-Propylbenzene and sec-Butylbenzene from the list and has added the controversial listing of hexavalent chromium total chromium.  EPA also has decided to revise the requirement to monitor 7 listed hormones from Assessment Monitoring to the Screening Survey.  Under the final rule, EPA estimates that approximately 6000 public water systems will now be required to monitor and report inormation on these substances that, generally speaking, lack "health-based standards set under the Safe Drinking Water At."   Upon release of this final rule, EPA also pledged to spend more than $20 million to support the new monitoring, "the majority of which will be devoted to assist small drinking water systems with conducting the monitoring."  EPA has posted additional information and background materials on the new rule on its website.