Feds: Ruptured W.Va. pipe may have been corroded - Article Photos 3/4

This image provided by the National Transportation Safety Board shows NTSB investigator Robert Sumwalt at the site of a gas line explosion in Sissonville, W. Va., Wednesday Dec. 21, 2012. Federal regulators say there have been 20 ``significant'' pipeline incidents involving deaths, injuries or major property damage in West Virginia in the last decade. (AP Photo/National Transportation Safety Board)