BOISE, Idaho (AP) — The federal government has taken over regulating underground injection wells in Idaho in a move that could boost the state's oil and natural gas production by making it cheaper to dispose of wastewater.

The U.S. Environmental Protection Agency on Monday issued a final rule transferring a portion of the state's Underground Injection Control program. The injection wells are used to return water and other fluids to the ground that come to the surface in the process of drilling for oil and gas.

The Idaho Department of Water Resources in August 2017 requested the change after failed attempts by the state to get approval from the EPA to regulate what are called class II injection wells.

"We think it's good because it has the potential for growth of the industry," said Mick Thomas, head of the Idaho Department of Lands' oil and gas division. Generally, increased production means more royalties for mineral rights owners and more tax revenue for the state.

Texas-based Alta Mesa has said its production of natural gas and oil in Idaho dropped because of the high cost of trucking the wastewater to evaporation ponds south of the Boise Airport. The company didn't respond to a request for a comment from The Associated Press on Tuesday.

Thomas estimated the cost of trucking the wastewater to be $9 per barrel. He said an injection well could lower the cost to $2 per barrel.

Jim Classen, an exploration geologist and member of the Idaho Oil and Gas Conservation Commission, said the wastewater would be injected 3,000 feet (900 meters) underground and beneath impermeable rock formations.

"In this particular case, the idea would be to re-inject them back into the same general reservoir from whence they came, in a well that doesn't have hydrocarbons (oil and gas) in it," he said. "It's better for the environment because you permanently get rid of it."

Austin Hopkins of the Idaho Conservation League, an environmental watchdog group, said the state shifting responsibility for the injection wells to the EPA means other state regulations that need updating involving agricultural drainage wells will languish.

"Without the incentive of the oil and gas injection well, I think these updates will take longer than they should," he said.

Also, some residents in oil and natural gas producing areas in Idaho have expressed concerns about the injection wells.

They have noted that in Oklahoma thousands of earthquakes have struck in recent years, many linked to the underground injection of wastewater from oil and natural gas production. State regulators there have directed several oil and gas producers to close some injection wells and reduce volumes in others.

Idaho wells, experts say, involve high-porosity sand formations from which oil and gas flow easily. That's different from the shale formations in Oklahoma that require hydraulic fracturing, or fracking, and the introduction of fluids to break open the shale. Access fluids are then sent down injection wells.

Idaho wastewater, Classen said, was already in the ground and is simply being put back where it came from, resulting in no net increase.

"It's a very safe way to dispose of these oil field waters," Classen said.