Talk about a revolving door. After finalizing a statewide ban on hydraulic fracturing, or fracking, the head of New York’s Department of Environmental Conservation is now going to work for an environmental group that opposes fracking.

New York DEC Commissioner Joseph Martens announced he will leave the department this month to rejoin the Open Space Institute, an environmental group he worked for before being tapped to become the state’s top environmental regulator. Martens previously headed the eco-group from 1998 to 2010, presiding over the nonprofit while it received funding to oppose fracking operations in New York. Martens was tapped to head the state DEC in 2011 by Democratic Gov. Andrew Cuomo.

Marten’s resignation from DEC comes just days after department finalized its a statewide ban on fracking. In his goodbye letter to DEC staff, Martens wrote that “at long last, we concluded our review of hydraulic fracturing and decided that there was simply too many unknowns and the possible risks too great to allow it to go forward.”

Now, Martens will return to the Open Space Institute, a conservation group that received money from the Park Foundation — a multi-billion dollar foundation that’s funded anti-fracking activism throughout New York state. The move was slammed by fracking proponents who argue New Yorkers deserve better than a revolving door environmentalist.

“The series of events leading to the fracking ban in New York would be a comedy if it weren’t such a tragedy to upstate workers and property owners,” Steve Everley, the team leader for the industry-backed group Energy In Depth, told The Daily Caller News Foundation.

“The administration based the ban, at least publicly, on a series of reports that were written, edited, and peer-reviewed by anti-fracking groups,” Everley said. “And now we learn that the state’s chief environmental regulator, having just finalized the ban, is heading back to the anti-fracking group he ran before he joined Cuomo’s team.”

The Democrat & Chronicle reported in 2013 that the Park Foundation’s “first fracking-related grant in 2008 went toward the formation of Catskill Mountainkeeper, which has become a leading anti-fracking group.” That grant was awarded to the Open Space Institute while it was headed by Martens.

The Park Foundation has spent “$3 million in fracking grants… from 2008 through 2011,” according to The D&C, and has spent much more since trying to push New York state, federal officials and other states to clamp down on fracking. Park even gave filmmaker Josh Fox $100,000 to make the sequel to his anti-fracking film “Gasland.”

Despite taking funds to fight fracking, Martens was made New York’s top environmental regulator. For years, his DEC conducted a study to see if fracking would be safe for New York. The first part of the study was released late last year, and it became clear Marten wanted to ban fracking.

Now he’s leaving. Everley said the only conclusion is that Martens decided he did what he had to do as a state regulator and environmental activist.

“I guess that means ‘mission accomplished,’ but it doesn’t help the struggling working families in New York who deserve better,” Everley said.

Energy In Depth has been critical of New York’s fracking ban. In April, the group released a report detailing the “staggering corruption” behind the ban and the supposedly scientific studies used to support blocking fracking for natural gas.

“[T]he Cuomo administration’s report relies on highly questionable sources, including research papers with strong ties to the fringe activists who helped hasten the ban in New York,” according Energy In Depth’s report. “Yet these same sources were misrepresented as purveyors and curators of ‘bona fide’ science by Cuomo officials.”

The Open Space Institute, however, is happy to be getting Martens back. Martens is returning to the group to work as a “consultant focusing his efforts on national climate change policy,” according to the group’s press release.

“Smart and effective land conservation has long been identified as an important tool in combatting the effects of climate change; establishing long-term strategies to protect our vital natural resources; and protecting key ecosystems and habitats,” OSI president Kim Elliman said in a statement. “Joe Martens’ voice and leadership will prove to be invaluable as we, as a nation, take on growing climate and environmental challenges. We enthusiastically welcome him to OSI and look forward to being part of the next chapter of his impressive career.”

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