Industry officials, meanwhile, turned out in Annapolis to warn members of a Senate committee not to turn away what could be an economic boon for two western counties.

The $10-an-acre fee would apply to lands leased for hydraulic fracturing, a drilling method that extracts the gas by blasting through layers of shale rock with a combination of water and chemicals. The bill would use the fee to pay for a study commissioned by Gov. Martin O'Malley.

Sen. Brian Frosh, a bill sponsor, said the governor has asked a state panel to examine the impacts "but it can't fully do its work because it doesn't have the money."

Frosh told the Senate's Education, Health, and Environmental Affairs Committee that the bill authorizes the return of any money that isn't used.

The bill, however, also says owners can be asked to pay more if the study costs more than the fee raises.

Drew Cobbs of the Maryland Petroleum Council told the panel he was concerned the bill could hurt the state's ability to compete with surrounding states. West Virginia and Pennsylvania are already seeing a boom in the new drilling technique, but also complaints about its impact on the environment, particularly ground water.

Farmers who turned out for the hearing took both sides of the issue.