HARRISBURG — Three decades ago, environmentalists and public officials rang the alarm when the price of fossil fuels shot up and drilling companies descended on western Pennsylvania's oil and gas fields in search of pay dirt.

The state Legislature responded with the 1984 Oil and Gas Act, which forced the companies to comply with strict new environmental standards — but also handed them a cushion that allowed them to keep secret most information about their below-ground discoveries for five years.

Now, with a fresh wave of exploration companies flocking to Pennsylvania in pursuit of natural gas in the sprawling Marcellus Shale rock formation, state legislators are considering peeling back that cloak of secrecy.

One proposal backed by several key senators would require disclosure of well-specific production data every six months in an effort to stimulate interest in drilling and bring Pennsylvania into line with major gas states.

"The thought is why is Pennsylvania so far out of line with what the industry is used to doing in other states?" said Sen. Gene Yaw, R-Lycoming, the bill's sponsor, whose rural, north-central Pennsylvania district is bustling with exploratory activity.

Opponents say the bill would take away their control over information they spent heavily to develop — data that give them a competitive advantage in the expensive race to tap the thick, black shale.

"It's like a trade secret," said Douglas E. Kuntz, president and CEO of Pennsylvania General Energy Corp. in Warren.

Even with the national recession depressing natural gas prices and exploration activity, analysts say the Marcellus Shale eventually could become the nation's biggest gas field.

And right now, Pennsylvania is seeing the biggest surge of interest in the rock formation.

The exploration companies are a mixture of newcomers to the Marcellus Shale and established players, which include some national companies as well as smaller in-state ones that consider Pennsylvania their bread and butter.

The looming tussle over the 25-year-old law is the latest on a growing list of regulatory dustups as Pennsylvania scrambles to catch up to a drilling rush that is rapidly changing its landscape.

The legislation written by Yaw would require that the updated information provided by drilling companies be made available on a state Web site.

Yaw's proposal would make Pennsylvania's law more like those in Louisiana, Texas, Oklahoma and Wyoming, where state agencies post well-specific production information online.

The just-introduced bill has not moved out of committee, and spokesmen for Gov. Ed Rendell and the House's Democratic majority declined to take positions on the issue.