CHICAGO (AP) — More than a year after a much-lauded compromise paved the way for high-volume oil and gas extraction in Illinois, the agency in charge of overseeing the practice has hired just four of 53 new employees it says it needs as it continues working to complete rules that drillers must follow.

The Department of Natural Resources has come under criticism from industry groups, lawmakers and other supporters of hydraulic fracturing who had hoped drilling could begin this summer. That scenario now appears unlikely.