CHICAGO (AP) — Leases have been signed on tens of thousands of acres in southern Illinois. Studies have hinted at the potential economic payoff of drilling for oil and gas deposits deep underground. But so far, oil and gas companies have held off on high-volume hydraulic fracturing in Illinois because the state lacks ground rules for the industry.

That could change under a regulatory bill being negotiated by officials from industry and agriculture, environmentalists, lawmakers and Attorney General Lisa Madigan. The bill, which would address everything from chemical disclosure to air and water pollution, could be introduced as soon as this week if the parties agree on the final language.

"From an industry perspective, they're not going to invest millions of dollars in Illinois if they don't know the regulations," said Mark Denzler, vice president of the Illinois Manufacturers' Association, which joined petroleum and transportation advocates and unions to form a coalition pushing for fracking regulations.