Drilling for natural gas in the Marcellus Shale in Pennsylvania's easternmost counties has been put on hold for months, if not longer.

On Wednesday, the Delaware River Basin Commission voted unanimously to draft new regulations to govern natural gas projects and not to issue any permits until the new rules are in effect.

The decision means that even as activity escalates throughout the state - nearly 900 Marcellus permits have been issued this year - no production drilling can be done in the Delaware watershed.

Adopting new rules could take six months to a year, commission executive director Carol R. Collier said Thursday.

It will stall indefinitely the lone application before the commision - for a well site in Wayne County at the northeastern tip of the state.

"I know there are many that want the gas-well drilling to move along quickly because of the economics and the issue of national security and providing clean fuel," Collier said. "But I really think we have to do it correctly and smartly. There's just too much at stake in the Delaware River basin."

Environmental groups cheered the decision, saying it was the "pause button" they have long sought statewide as the tally of explosions, spills, and pollution incidents mounts. So far this year, the state Department of Environmental Protection has initiated 116 enforcement actions against drillers.

"The DRBC has taken a sensible and laudable step today toward keeping gas drilling from running wild here," said Maya van Rossum, the Delaware riverkeeper.

Spokesman Tim O'Leary of Stone Energy Corp., which is seeking commission approval for a well, said only one of its 14 wells in the region was in the Delaware watershed.

"Stone Energy looks forward to working with the DRBC in answering any remaining questions," he said.

The Marcellus Shale Coalition, an industry group, did not respond.

John Hanger, secretary of the state Department of Environmental Protection, which also has regulatory authority over natural gas drilling, said the two agencies should work together so no conflicts arise and "to provide strong oversight of this industry."

The commission is an interstate agency, formed by a federal compact, that has legal authority over water quality and quantity in the basin. The governors of the four basin states - Pennsylvania, New Jersey, New York, and Delaware - plus a federal appointee are commissioners, but they often send representatives.

The New Jersey representative at Wednesday's meeting, Fred Sickels of the state DEP water-supply division, said that with all the activity, "the cumulative impacts could be significant if there aren't appropriate safeguards."

Pennsylvania's northeastern counties - where the shale region and the Delaware watershed overlap - have been deemed a high-stakes area.

The pressure to drill there could be even more intense than elsewhere. Geological maps indicate that corner of Pennsylvania is a sweet spot with huge quantities of natural gas.

More than 6,000 leases have been signed in Wayne County alone, said Brian W. Smith, chairman of the Wayne County supervisors.

No drilling other than test wells, which are still allowed, has been done in the watershed.

But environmental concerns are high. The Delaware River from Hancock, N.Y., south to Trenton is so clean that it is under stricter, "special protection waters" regulations. Also, the federal government has designated portions of the river wild and scenic areas worthy of enhanced protection.

And downstream - where the river's quality is the sum of everything that has occurred upstream - are Philadelphia's water intakes.

Proponents say natural gas drilling is adding millions of dollars to local economies and has environmental benefits because the fuel burns cleaner than coal.

Critics say the drilling process is fraught with hazards and the regulatory baseline is inadequate.

In March, Philadelphia City Council unanimously passed a resolution asking the commission not to approve any applications in the Marcellus Shale until a full environmental impact assessment is done.

At the time, the commission was considering the Stone Energy proposal. A decision, which many felt would have set a precedent, was not expected until July at the earliest.

Stone Energy received DEP permission for the well in March 2008 and began construction without commission approval.

That December, the commission and Stone Energy reached a settlement agreement that required the company to submit an application and pay a $70,000 penalty.

Stone Energy submitted two applications - one for the well and one for a withdrawal of 700,000 gallons of water a day from the west branch of the Lackawaxen River - a basin waterway - for fracturing the well so the gas can be extracted.

The application was submitted to the commission more than a year ago. But unlike the DEP, which has 45 days to consider a well permit and can deny one only under specific conditions, the commission has no deadline. No clock is ticking.

During a public-input period, the commission received more than 2,000 comments.

"We're looking at things that have happened to the west of us and what needs to be put in place to prevent that," Collier said. "We're learning a lot, and we want to do it right."

Contact staff writer Sandy Bauers at 215-854-5147 or sbauers@phillynews.com. Visit her blog at http://go.philly.com/greenspace