Gov. Andrew M. Cuomo’s administration announced on Wednesday that it would ban hydraulic fracturing in New York State because of concerns over health risks, ending years of uncertainty over the disputed method of natural gas extraction.
State officials concluded that fracking, as the method is known, could contaminate the air and water and pose inestimable dangers to public health.
That conclusion was delivered during a year-end cabinet meeting Mr. Cuomo convened in Albany. It came amid increased calls by environmentalists to ban fracking, which uses water and chemicals to release oiland natural gas trapped in deeply buried shale deposits.
The question of whether to allow fracking has been one of the most divisive public policy debates in New York in years, pitting environmentalists against others who saw it as a critical way to bring jobs to economically stagnant portions of upstate.
Mr. Cuomo, a Democrat who has prided himself on taking swift and decisive action on other contentious issues like gun control, took the opposite approach on fracking. He repeatedly put off making a decision on how to proceed, most recently citing a continuing — and seemingly never-ending — study by state health officials.
On Wednesday, six weeks after Mr. Cuomo won re-election to a second term, the long-awaited health study finally materialized.
In a presentation at the cabinet meeting, the acting state health commissioner, Dr. Howard A. Zucker, said the examination had found “significant public health risks” associated with fracking.
Holding up scientific studies to animate his arguments, Dr. Zucker listed concerns about water contamination and air pollution, and said there was insufficient scientific evidence to affirm the long-term safety of fracking.
Dr. Zucker said his review boiled down to a simple question: Would he want to live in a community that allowed fracking?
He said the answer was no.
“We cannot afford to make a mistake,” he said. “The potential risks are too great. In fact, they are not even fully known.”
New York has had a de facto ban on the procedure for more than five years, predating Mr. Cuomo’s election. Over the course of his first term, the governor at times sent conflicting signals about how he would proceed.
In 2012, Mr. Cuomo flirted with approving a limited program in several struggling Southern Tier counties along New York’s border with Pennsylvania. But later that year, he bowed to entreaties from environmental advocates, announcing instead that his administration would start the regulatory process over by beginning a new study to evaluate the health risks.
Polls showed public opinion divided over the issue, and the governor felt pressure from both sides.
Mr. Cuomo had focused a great amount of attention on trying to improve the economic climate upstate, and fracking appeared to offer a way to bring new life to struggling areas atop the Marcellus Shale, a subterranean deposit of trapped gas that extends across much of New York, Pennsylvania and West Virginia.
Mr. Cuomo’s Republican opponent in the election this year, Rob Astorino, the Westchester County executive, promised to allow fracking, and he accused the governor of squandering an opportunity to help upstate regions.
But the governor has also faced strong opposition from groups worried about the effects of fracking on the state’s watersheds and aquifers, as well as on tourism and the quality of life in small upstate communities.
Opponents were aided by celebrities like Yoko Ono, who drew attention to their cause. As he traveled around the state, Mr. Cuomo was hounded by protesters opposed to fracking, who showed up at his events and pressed him to impose a statewide ban.
The governor’s uncertain stance on fracking also hurt his standing with some liberal activists. Pledging to ban fracking, Zephyr Teachout, a law professor, won about a third of the vote in the Democratic primary in September, a strong showing that Mr. Cuomo later attributed in part to support from fracking opponents.
Complicating matters, dozens of communities across New York have passed moratoriums and bans on fracking, and in June, the state’s highest court, the Court of Appeals, ruled that towns could use zoning ordinances to ban fracking.
Recognizing the sensitivity of the issue, Mr. Cuomo both affirmed the fracking ban on Wednesday and tried to keep some distance from it, saying he was deferring to the expertise of his health and environmental conservation commissioners.
Nevertheless, environmental groups cast the governor as a hero.
Michael Brune, the executive director of the Sierra Club, said Mr. Cuomo “set himself apart as a national political leader who stands up for people” over the energy industry.
Advocates of fracking accused him of giving in to environmentalists’ efforts to stoke public fears.
Brad Gill, executive director of the Independent Oil and Gas Association of New York, said, “While industry will find opportunity elsewhere, our hearts go out to the farmers and landowners in the Southern Tier whose livelihoods in New York State are in jeopardy.”