The Marcellus shale drilling boom has tapped a bounty of natural gas worth billions, but Inquirer reporters Joseph Tanfani and Craig R. McCoy found that thousands of miles of high-pressure pipelines carrying the gas to market are being installed with no government safety checks – no construction standards, no inspections, and no monitoring. In fact, state and federal regulators don't even know where many lines are located.

These new "gathering" pipelines that connect to the wells are big – two feet or more in diameter – and push gas at the same powerful pressures as the transmission lines that cut across the continent. And they are potentially just as dangerous. While accidents are rare, when things go wrong, the results can be devastating – and deadly.

For nine months, the reporters pored over thousands of pages of documents from an alphabet soup of government agencies – PHMSA, FERC and the PUC. They delved into data bases, drew on GIS mapping, and compiled spreadsheets.  They conducted scores of interviews with federal and state regulators, pipeline engineers, public officials, executives of gas-drilling and pipeline companies, industry trade groups, union officials, leaseholders, environmentalists, activists of every stripe, and ordinary folks.

And they spent days tramping up hill and down dale, talking to the crews that were actually installing the lines.

John Tierno provided the graphics. Michael Bryant was the photographer. Rob Kandel, Frank Wiese and Josh Cohen designed the "Deep Drill" online package. The Inquirer pages were designed by Steve Kelly. And the project editor was Mike Leary.