State lawmakers have been talking about Marcellus Shale gas issues for more than a year. Earlier this year, they pledged to take action by Oct. 1. Time is running short on that promise, and there is no excuse for a failure to meet the deadline.

Setting a reasonable natural gas extraction tax, in line with tax levels in neighboring states that also have Marcellus Shale gas deposits, is reasonable and doable. The tax would bring needed revenue to the state, but it should not create an uncompetitive environment that would drive drillers to other states.

It's also reasonable to set aside some of that tax revenue for environmental programs, such as well-inspection costs and environmental oversight tied to increased activity, and also money to repair roads damaged by heavy trucks used for drilling operations.

One stumbling block to passing a tax bill has apparently been over disagreement on how to split money between areas related to gas drilling and the general fund, where a major budget gap remains. It should be possible to agree to an equitable split between environmental areas related to Marcellus Shale gas production and the general fund.

More interesting than the debate over taxes on Marcellus gas, Republicans are offering a proposal to expand the market for natural gas, which is essential if the supply of gas is going to increase and economic benefits are going to continue to flow to Pennsylvania.

Without expanded markets for natural gas, the price will fall with higher supplies from new Marcellus wells. Lower prices for gas would reduce drilling activity and, therefore, the economic benefits.

Among other ideas, Republicans in Harrisburg say they would like the 16,000 state vehicles to eventually be converted to run on natural gas. Certainly, larger vehicles, such as buses and big trucks, should be converted. The value of converting regular cars might require more study.

While it's worth examining whether it makes sense to convert cars to run on natural gas, it's also worth examining why the state owns 16,000 vehicles. Justifying the size of this state fleet should happen along with the conversion study.

But conversion of larger vehicles, notably public transit buses and 18-wheel tractor-trailer rigs is a good idea. These categories of vehicles, typically diesel-powered, consume a significant portion of the oil used in the United States each year. It's been estimated that if big rigs and city buses across the country were converted to natural gas, oil consumption would drop enough to eliminate the need for oil imported from other countries. It also would help clean the air.

Such thinking is what's behind famed Texas oilman T. Boone Pickens' push for a government-backed conversion of the nation's big-rig fleet to natural gas. He says the conversion would eliminate the need for the U.S. to import oil from the Middle East and countries hostile to the United States.

Conversion of engines to run on natural gas will not be cheap, but potential cost savings are considerable. And few will deny the appeal of running much of the nation's transportation system on a domestic source of fuel, which also happens to be cleaner-burning.

Natural gas offers a domestic energy supply, for vehicles and electricity generation, that is cleaner than coal and has more political and environmental appeal than imported oil.

Pennsylvania lawmakers should get moving on natural gas legislation. They should do it soon, and in public, with transparency over gas industry campaign contributions.