ALBANY – New York had been considering a "phased rollout" of large-scale hydraulic fracturing in the months prior to deciding to ban it, with the proposal received well by public-health experts the state had asked for advice.

The revelation was included in a series of letters from three experts from top universities, who had been contracted by the state to review its proposals for shale-gas drilling and recommend ways to improve them.

The letters, written in late 2012 and early 2013, were first disclosed by the state Department of Health last month as part of its report recommending the state not proceed with fracking, the controversial technique used to fracture shale formations and release natural gas.

"I agree with the notion of a phased approach to (high-volume hydraulic fracturing) gas-development that would allow public health problems to be identified earlier, and reduce problems resulting from overly rapid growth ('boom and bust')," wrote Lynn Goldman, dean of public health at George Washington University, in a letter dated March 4, 2013. She was responding to documents provided by the state.

The so-called "phased approach" was referenced in letters from Goldman and the other two experts, UCLA's Richard Jackson and the Colorado School of Public Health's John Adgate.

Ultimately it was scrapped: Gov. Andrew Cuomo's administration announced Dec. 17 that it would soon issue a legally binding document preventing high-volume fracking in New York.

The state Department of Environmental Conservation "was considering a number of mitigations and alternatives in evaluating (high-volume hydraulic fracturing) in order to determine if it could be done safely," the agency wrote in a statement Friday.

When Cuomo's administration launched its separate health review of large-scale fracking in September 2012, it also announced it would hire outside experts to help inform the process. In all, the state spent a total of $48,000 to contract with Goldman and Adgate's employers, while Jackson worked pro bono.

The three experts were provided voluminous documents from Cuomo's administration outlining its assessment of fracking and its potential impacts, as well as the various proposed rules the state was considering to regulate the process. They included draft versions of the state's health review and Environmental Impact Statement that haven't been released publicly.

The letters suggest the state had put together a draft plan that would impose additional tight restrictions on gas drillers, in addition to drilling bans in the New York City and Syracuse watersheds that were previously announced.

"The (Public Health Review) and (Supplemental Generic Environmental Impact Statement) describe a phased start to shale gas development that is coupled with baseline and subsequent monitoring of potential impacts," Adgate wrote on March 3, 2013.

The state's draft analysis of fracking and its proposed measures for limiting its environmental effect received praised from both Adgate and Goldman, the latter of whom called it "a model for other states that are considering or undertaking these operations." Jackson said the state had practiced "due diligence" but didn't express strong opinions about its plan.

"If shale gas development goes forward in New York, the approach outlined in the (public health review) represents a viable strategy for protecting public health," Adgate wrote. "Prevention of impacts will, however, require a strong partnership between the DOH, DEC, and the local governmental bodies engaged in land use planning, monitoring, and enforcement."

Neither Adgate nor Jackson responded to requests for comment.

In an interview with Gannett's Albany Bureau, Goldman confirmed the state's draft reviews had proposed opening up New York's portion of the Marcellus Shale in phases, allowing drillers to slowly move across the region while also allowing the state to closely monitor any potential health or environmental impacts from fracking.

"This was an idea that I actually thought was a really good idea -- that rather than opening up all of the natural-gas reserves in the state, that there might be a phased approach to development," Goldman said. "So rather than having a boom/bust in the whole region, you would have the development process moving from area to area. It would tend to spread out both the positive and negative impacts."

Bob Williams, an environmental consultant and member of a coalition of pro-fracking landowners in Windsor, Broome County, questioned why Cuomo's administration decided to prevent high-volume fracking when at least two of the outside experts had generally favorable things to say about the state's previous plan.

"To me, it says somebody had a different agenda," Williams said.

Both the state Department of Health and Department of Environmental Conservation declined to provide copies of the documents that were provided to the experts without a formal request under the Freedom of Information Law, a process that often takes weeks or months to fulfill.

In a statement, the Department of Health said its review was informed by a number of different sources, not just the opinions of the three outside consultants.

"Their advice and input were taken into account along with all the other information that was obtained during the health review," according to the agency.

Goldman said she wasn't surprised the state ultimately decided to prevent high-volume fracking from moving forward, especially after the state's review continued long after the experts' contracts had expired.

She said either a phased-in approach or a halt on fracking to allow further scientific review was justifiable based on the state documents she reviewed.

Cuomo's administration ultimately chose the latter option, with acting Health Commissioner Howard Zucker recommending a ban "until the science provides sufficient information to determine the level of risk to public health."

Cuomo had faced increased pressure from anti-fracking groups to ban the practice. They trailed him at public events since he took office in 2011. But Cuomo said the decision wasn't about public pressure; polls showed voters were split on the issue. He said his staff made a compelling case about the health risks of fracking.

"I don't think jobs should have to come at the cost of public health, and we can come up with an economic development strategy for the Southern Tier that develops the economy, produces jobs, but doesn't put public health at risk," Cuomo said last month in a radio interview.

Walter Hang, owner of environmental database firm Toxics Targeting and an Ithaca-based organizer, said Zucker's determination was vindicating. He said the efforts by fracking critics obviously had an effect on the state's decision-makers.

"Most importantly I feel incredibly grateful that I was able to work with so many New Yorkers to protect our home state from shale fracking harm," Hang said. "That is exactly what I set out to achieve more than five years ago."

Now, the DEC has to finalize its Environmental Impact Statement in order for the fracking ban to take effect. The DEC's next move will be closely watched by the natural-gas industry, which will be looking for any procedural missteps that may allow for legal challenges to the ban.

On Friday, the agency gave no indication when that process may be completed. In December, DEC Commissioner Joseph Martens said the document would be finalized in early 2015.

"DEC is diligently working to complete the (Supplemental Generic Environmental Impact Statement)," the agency wrote in its statement. "At this point, we can't provide a more exact date or what documents the SGEIS would include."

JCAMPBELL1@gannett.com

Twitter.com/JonCampbellGAN

To read the state's Public Health Review of fracking, visit https://www.health.ny.gov/press/reports/docs/high_volume_hydraulic_fracturing.pdf. The experts' letters begin on page 57.