Recently, we wrote about former Pennsylvania Gov. Ed Rendell's connections to the natural gas industry after he published a pro-fracking op-ed in The New York Daily News.

Following our story, Rendell's column — which called on New York officials to lift a ban on the drilling technique — was updated to disclose that he is a paid consultant to a private equity firm with natural gas investments.

Rendell assured us in an interview before the first story that despite his role with the private equity firm, he had no "pecuniary interest in the natural gas industry doing well."

But the story doesn't end there. One entity that indisputably has an interest in the industry is Rendell's longtime home outside of politics: the law firm Ballard Spahr of Philadelphia.

Rendell is currently special counsel at the firm, and is a member of its energy and project finance and environment and natural resources practice areas, his spokeswoman said.

The firm touts its work "on the forefront" of the development of the Marcellus Shale, the formation under Pennsylvania and other states from which a vast quantity of natural gas is now being extracted.

In 2011, the publication AOL Energy named Ballard Spahr one of the top five energy law firms in the country. AOL cited Ballard Spahr's "deep presence in Pennsylvania" that "put it on the doorstep of the Marcellus Shale natural gas field," a "major source of controversy and legal work as developers work in heavily populated and closely monitored areas."

A week after leaving the governor's office in 2011, Rendell rejoined the firm, where he had given up his job as partner when he was elected in 2003. As governor, he presided over the fracking boom in Pennsylvania.

Has he worked for natural gas interests in his role at Ballard Spahr?

"Governor Rendell cannot comment on what areas he may or may not work on for clients of the firm," Kirstin Snow, his spokeswoman, said in an email.

Another attorney in Ballard Spahr's Philadelphia office, Harry Weiss, has "advocated for an oil and gas company at both the state and federal levels during regulatory and policy debates on impact of shale gas exploration on ground water supplies," according to the firm. He also represents landowners in lease negotiations with gas companies.

The firm did not respond to a request for comment about Rendell's work.