FILE - In this Dec. 15, 2010 file photo, Jim Riggio, the plant manager for the Beaver Falls Municipal Authority, shows the filtering rig that the treatment plant used to develop improvements in the ... more 
FILE - In this Dec. 15, 2010 file photo, Jim Riggio, the plant manager for the Beaver Falls Municipal Authority, shows the filtering rig that the treatment plant used to develop improvements in the treatment of the water at the intake facility in Beaver Falls, Pa. Citing potentially unsafe drinking water, on Tuesday April 19, 2011, Pennsylvania state called on companies drilling in the Marcellus Shale natural gas formation to stop taking wastewater to 15 treatment plants by May 19, 2011. The announcement was a major change in the state's regulation of gas drilling and came the same day that an industry group said it now believes drilling wastewater is partly at fault for rising levels of bromide being found in Pittsburgh-area rivers. less 
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Associated Press | Photo By Keith Srakocic, File
Tue, Apr 19, 2011 4:27 PM EDT