(AP) -- Hundreds of people are attending a U.S. Environmental Protection Agency hearing in southwestern Pennsylvania on a controversial natural gas drilling technique called hydraulic fracturing, or "fracking."
Drilling into the rich Marcellus Shale gas reserve below Pennsylvania is growing rapidly.
Fracking is currently exempt from federal regulation, and is governed by states. The EPA is studying its effect on human health and the environment.
The oil and gas industry says it's been safe for decades and is a crucial tool in the nation's energy future.
The hearing began at 6 p.m. Thursday in Canonsburg.
The EPA says 130 people are scheduled to speak. Attendees include people who work for drilling companies or contractors and others who are worried about the impact of drilling on their property.
Explore further: Drought may take toll on Congo rainforest, study finds