Pennsylvania Gov. Tom Wolf wants more data on the potential health impacts of unconventional oil and gas development.

He’s been prodded by a public outcry from some in the southwest part of the state where natural gas development is heavy. Wolf said this week that he has asked state Department of Health Secretary Rachel Levine to “assess the best ways to spur additional academic, science-based study of potential public health impacts from oil and gas development.”

He invited the public to continue providing information to the health department as well. The directive stops short of the investigation that hundreds of residents and organizations had called for in an open letter to the governor delivered earlier this week. Concern has grown in recent weeks over a series of investigative stories published by the Pittsburgh Post-Gazette, detailing dozens of cases of “childhood and young adult” cancers in four southwest Pennsylvania counties, including more than two dozen cases of the rare bone cancer known as Ewing Sarcoma.

Public meetings have been held and the communities have heard from expert panelists on the matter. Oil and gas development, along with other industrial sources, such as a uranium mill tailings site in the region have been floated as possible causes.

However, Wolf stressed that there is currently no known environmental cause of Ewing Sarcoma. Indeed, cancer is common, millions of cases are diagnosed every year and nearly one-third of the U.S. population will be diagnosed in their lifetimes, making it hard to link clusters to any one cause, according to the American Cancer Society.

In a separate statement, Levine noted that Wolf’s administration has investigated hundreds of complaints from citizens about the potential public health impacts from oil and gas development.

“As a pediatrician and a public health advocate, the public can rest assured that if I knew that we were inadequately protecting public health, I would make the case clear to Gov. Wolf,” she said. “But I believe that we do not have enough information to make a determination in this case.”

The health department’s Bureau of Epidemiology also just completed a years-long review of literature regarding the potential health impacts of hydraulic fracturing. It was completed along with epidemiologists in Colorado and published last week in the International Journal of Environmental Research and Public Health. The review found 20 published epidemiological studies that evaluate potential links between oil and gas operations and health outcomes. It concluded that more study and research is needed to properly gauge any impacts.

The industry appeared unphased by the Wolf administration’s desire for more information.

Marcellus Shale Coalition President David Spigelmyer said the organization “welcomes additional, science-based objective research from the Department of Health that considers all possible variables surrounding the recent instances of cancer in the region.” He added that “as an industry made up of tens of thousands of Pennsylvanians, we are deeply committed to protecting and enhancing the health, safety and environment of the communities where we are privileged to live and operate.”

While Levine explores ways to produce more data on the issue, Wolf said the health department would continue to monitor and study cancer incidents in southwest Pennsylvania.

Over the last decade, the state has become a leading hydrocarbon producer and now churns out more natural gas than any other state except Texas. Production from the Marcellus and Utica shales from practically every corner of the state was more than 6 Tcf in 2018