INDIANAPOLIS (AP) — The man who oversees Indiana’s oil and gas industries says the state is studying whether hydraulic fracturing used by many operators can cause earthquakes in the state.

Indiana Department of Natural Resources Oil and Gas Division Director Herschel McDivitt is a member of a group of U.S. drilling state officials, seismologists, academics and others who released a report Monday examining how states handled various seismic incidents linked to fracking.

McDivitt says the DNR began a study about a year ago in collaboration with the Indiana Geological Survey to assess whether fracking can induce earthquakes in Indiana.

He says about a quarter of Indiana’s oil and gas wells have been fracked in an effort to produce more oil and gas.