"PITTSBURGH -- Unions and environmentalists have found one point of agreement in the bitter debate over the natural gas drilling boom: fixing leaky old pipelines that threaten public health and the environment. It's a huge national effort that could cost $82 billion."

"The leaks are a problem because methane, the primary component of natural gas, is explosive in high concentrations and is also a potent greenhouse gas that contributes to global warming.

The Department of Transportation estimates that more than 30,000 miles of decades-old, decaying cast-iron pipe are still being used to deliver gas nationwide. In 2011, the American Gas Association estimated the billions in costs for replacement or repair."

Kevin Begos reports for the Associated Press December 8, 2013. [2]