HARRISBURG — Pennsylvania Gov. Tom Wolf said Friday his administration will spend $3 million on a pair of studies to explore the potential health effects of the natural gas industry, taking action after months of impassioned pleas by the families of pediatric cancer patients who live in the most heavily drilled region of the state.

Dozens of children and young adults have been diagnosed with Ewing sarcoma and other forms of cancer in a four-county area outside Pittsburgh, where energy companies have drilled more than 3,500 wells since 2008.

Ewing has no known environmental cause, and gas industry officials say there is no evidence linking pediatric cancer to drilling. But the families nevertheless suspect that drilling and hydraulic fracturing, the method that energy companies use to extract natural gas from shale rock, played a role. They have been pressing the Wolf administration for an investigation into any possible link between this extremely rare form of bone cancer and shale gas development — and confronted Wolf himself at the Capitol on Monday.

The research, Wolf said, is meant to address “the concern that there is a relationship between hydraulic fracturing and childhood cancers.”

“We're very happy to hear this. We feel as though our voices have been heard and hopefully, through the research, maybe they will come up with some answers to these mysterious rare cancers,” said Christine Barton, whose 22-year-old son, Mitch, has been battling Ewing sarcoma for nearly a year. She said the family lives within two miles of four well pads, with the closest one a half-mile down the road.