Advances in the hydraulic fracturing, or fracking, drilling technique have revolutionized the natural gas industry, but researchers said more must be done to evaluate what the shale boom means for the those living near wells.

Health groups have concerns including possible air and water pollution from fracking, especially since some operations take place very close to homes and schools.

"We are leaping before we are looking," said Jerome Paulson, of the Mid-Atlantic Center for Children's Health and the Environment, at a conference focused on shale gas and public health.

"Those who are drilling and extracting ... have not done the human health research and ecological studies to assure that the process and chemicals they use are the least hazardous possible," Paulson said.

The Mid-Atlantic center and Physicians, Scientists and Engineers for Healthy Energy sponsored the conference with hopes of setting up a consortium to collect and assess scientific data on the effects of shale development on the public.

Past studies of shale gas development have provided varying results sometimes even when they were based on the same information, said Vikas Kapil, a chief medical officer at the Centers for Disease Control.

"This sort of begs for some systematic and organized way to begin to think about how we collect data, the kind of data we collect, and to have some common understanding and transparency in how this work is laid out and organized," Kapil said during a speech at the conference.

Fracking involves injecting water mixed with sand and chemicals into shale formations at high pressures to extract fuel.

The recent spread of fracking has raised concerns among environmentalists, public health advocates and some neighbors of shale wells who worry about issues such as water contamination and increased truck traffic. Some have also linked earthquakes to disposal of waste water from shale wells.

Industry groups say fracking has been done safely for decades and that drillers have worked diligently to minimize effects of drilling.

PUSHING THE PAUSE BUTTON

The Environmental Protection Agency is expected to release the first results of its analysis of the effects of shale development on drinking water later on this year.

Already, a recent EPA draft report showed that harmful chemicals from fracking fluids were likely present in a Wyoming aquifer near the town of Pavillion.

Still, many researchers at the conference complained that federal and state government seemed to be woefully behind the curve when it comes to assessing the health effects of shale gas development.

Adam Law, a physician with Weill Cornell Medical College, which helped organize the conference, said the industry has not upheld its responsibility to ensure that its practices are safe and to examine the consequences for public health.

The conference was not conceived to be activist, Law told Reuters on the sidelines of the forum. "This is an attempt to bring the evidence-based community into dialogue."

While Law said the conference was not "anti-fracking," he said he believes authorities should "push the pause button" on shale drilling in new areas until thorough studies can be completed.

An industry-backed group that promotes shale gas production said drillers have been using fracking for more than 65 years and the only difference in the current shale boom is the use of horizontal drilling.

"What these guys are essentially arguing is that the mere act of turning a drill bit horizontally, thousands of feet underground, represents a greater risk to health than drilling a well straight down into the formation," said Chris Tucker, a spokesman for Energy In Depth.

"It's a position completely unmoored from the facts, from the science and from the demonstrable history of safe operations to which this industry lays claim," he added.

(Editing by David Gregorio)

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