Environmental groups are rallying to support legislation that would formally ban hydraulic fracturing for natural gas in Maryland until studies are finished of the controversial drilling technique.

Del. Heather Mizeur, a Montgomery County Democrat, says she will introduce a bill in the next General Assembly session to bar any "fracking," as the technique is commonly known, unless and until state officials determine that it can be done without harming drinking water or the environment.

Mizeur was expected to announce her intentions at a press conference this morning on Federal Hill in Baltimore. She's to be joined there by environmental activists, who contend gas extraction using fracturing in other states has fouled ground water, streams and the air. Industry officials say fracking is safe and problems critics cite are unrelated to the drilling technique.

Maryland already has a "de facto moratorium" on fracturing, Mizeur said, as state agencies have put on hold three applications to drill in western Maryland while they carry out an order by Gov. Martin O'Malley to conduct a three-year study of fracturing's environmental impacts and whether they can be prevented through tighter regulations.

But Mizeur said she wants a formal legislative ban to foil what she called the gas industry's "waiting game," as it has refused to fund the three-year study, which state regulators say they lack the money to do properly.  Industry officials opposed a bill Mizeur sponsored this year that would have funded the study with fees on gas drilling leases in western Maryland, and it died.

"The oil and gas industry is playing a game of chicken with us, waiting out the clock,'' she said. "I want to make it very clear .. that the public policy of the state of Maryland is there will be no fracking until comprehensive scientific studies .. are completed."

Drew Cobbs, executive director of the Maryland Petroleum Council, said the industry would oppose Mizeur's bill, as it objected to paying for studies without any assurance it would eventually be able to drill for gas.

A spokesman for the Maryland Department of the Environment said that only one of three applications to drill for gas using hydraulic fracturing is still being actively reviewed, involving a site southwest of Oakland. The other two, seeking approval to drill on seven sites, have been declared inactive because the companies have not supplied information regulators requested, he said.