U.S. EPA's draft report of its investigation of groundwater contamination related to fracking in Pavilion, Wyoming, marked the first time EPA publicly indicated that fracking could have caused contamination of a drinking water aquifer. This draft report has drawn sharp criticism since its publication on December 14, 2011. 

Recently, the U.S. Geological Survey ("USGS") released results of additional groundwater sampling in Pavilion in a report dated September 26. EPA stated that these data are "generally consistent" with the data upon which EPA relied to prepare its draft report. Critics note, however, that USGS collected samples from only one of the two monitoring wells EPA put in place. USGS stated that it declined to test water in one of the two monitoring wells because the volume of water flow was not high enough to get reliable readings. Critics cite this as an indication that the monitoring wells were improperly constructed. 

On October 16, EPA extended the public comment period for the draft report until January 5, 2013 to give the public an opportunity to comment on the USGS data. EPA has scheduled a scientific peer review of its draft report which is expected to commence at the close of the public comment period.