PITTSBURGH — Some people are absolutely sure gas drilling threatens public health, while others are absolutely sure it

doesn’t.

Geisinger Health Systems is looking for more facts on the debate.

“Our concern is getting reliable data so we know what to do for our patients,” said David Carey, director of Geisinger’s Weis Center for Research in Danville, Pa.

Geisinger serves many patients who live in areas that have seen a recent boom in Marcellus Shale gas drilling. The gas-rich formation thousands of feet underground has generated jobs, billions of dollars and concerns about possible environmental and public health impacts from thousands of new wells.

“There’s a real need for reliable information for policymakers,” Carey said, yet some of the debate on the issue has been more emotion-driven than science-driven.

“Lack of data has not led to a lack of opinion,” Carey noted.

But with state and federal budgets under intense pressure, there hasn’t been much money available for serious medical research. Then over the last year, executives at Geisinger realized they had a big head start.

“We have a very long history of caring for patients in this region,” Carey said, noting the company serves 2.6 million patients and operates hospitals, clinics, and an insurance program in 44 north central and north eastern counties. That means they have vast troves of health care data, concerning everything from cancer to car accidents to asthma attacks.

“We can map the clinical data in both space and in time,” Carey said, meaning they can compare health in areas with gas drilling to similar areas where it isn’t happening.

Carey said the company isn’t presuming anything about the issue, though it is aware of both concerns and the economic value of the shale boom.

“Our position is, let’s collect the data and find out,” he said.

It may fall to private companies to do some of the work.

Until a few months ago, Pennsylvania public health officials had expected to get a share of the revenue being generated by the state’s new Marcellus Shale law, which is projected to provide about $180 million to state and local governments in the first year.

But representatives from Republican Gov. Tom Corbett’s office and the state Senate cut the health appropriation to zero during final negotiations, so now the state Department of Health is left with a new workload but no funding to examine whether gas drilling impacts health.

Many federal and state regulators say hydraulic fracturing is safe when done properly, and that thousands of wells have been drilled with few complaints of pollution. But environmental groups and some doctors assert regulations still aren’t tough enough and that the practice can pollute groundwater and air.

The claims and counterclaims have been so extreme that some health experts feel the fear and confusion that’s been generated among the public is a problem by itself. Bernard Goldstein, a professor emeritus at the University of Pittsburgh School of Public Health, said experience has shown that patient trust is a key component in health care.