Feb. 20--A Houston company is pushing to build a cavernous underground facility near Eloy, big enough to hold the University of Arizona's football stadium, to store natural gas for homes and businesses.

Multifuels LP is proposing a complex and controversial plan to inject fresh water into salt formations deep below ground. Then it would pump out the resulting saltwater and re-inject that water into a still-deeper, saltwater-dominated aquifer for ultimate disposal. The cavern left behind by the original water pumping would then be used to store natural gas that could be used by utilities such as Southwest Gas during peak usage periods.

But before it can build the $220 million project about 50 miles northwest of Tucson, the company needs an exemption from state permitting requirements aimed at protecting underground water supplies from contamination. That's because the Arizona Department of Environmental Quality has told the company that existing law won't let it issue a permit to inject brine wastewater into groundwater.

Thursday in Phoenix, a House committee, with Republicans in the majority, voted 5-3 to recommend a bill to authorize the exemption. This would be the first facility of its kind in Arizona. The bill would exempt other future gas storage facilities from state permitting requirements.

The bill, which cleared the House Energy and Water Committee, would need the Legislature and governor's approval.

This would be approximately the 25th exemption from the state's groundwater-protection permitting requirements since they were instituted in 1986.

Jobs -- the project would generate about 200 temporary construction jobs and up to 20 permanent jobs -- and the need for places to store natural gas are two reasons supporters are pushing the project. Fear of contamination of the aquifer from the injected water -- which would be up to eight times saltier than ocean water -- is driving the opposition.

Supporters include the mayor of Eloy, Southwest Gas, Arizona Public Service Co. and the Pinal County Board of Supervisors.

A Southwest Gas official said the company would be interested in purchasing gas from the facility but needed more details about the project.

Without a source of gas storage, the company has to have enough pipeline capacity to hold enough gas for peak hours.

Having the underground storage helps utilities avoid price fluctuations, said Yvonne Hunter a spokeswoman for Pinnacle West Capital Corp., Arizona Public Service's parent company.