Following New York’s ban on hydraulic fracturing, the technique deemed too risky north of the Pennsylvania border will proceed as usual in the commonwealth.

The American oil and gas industry is regulated mostly by state agencies applying a patchwork of federal and state laws. Though New York and Pennsylvania have different environmental laws, legal experts say their separate stances on shale gas is more the result of differing politics and attitudes.

“I think from the New York perspective, they couch it on environmental grounds but the reality is that it’s political,” said Harrisburg environmental and land use attorney Bill Cluck.

Last week, New York finalized its fracking ban after a seven-year review under a 1995 law that requires all governments to conduct a full scientific review before making any decisions that could harm the environment, such as issuing a drilling permit.

According to the New York Department of Environmental Conservation, fracking comes with “potential significant adverse environmental and public health impacts” and “limited economic and social benefits.”

Citing a long list of possible harms to the land, air and water, the DEC argued allowing the technique is not compatible with its State Environmental Quality Review Act. Hydraulic fracturing, or fracking, extracts gas from tight rock by cracking it with chemically treated water and sand under high pressure. It happens soon after a well is drilled.

Pennsylvania is one of 34 states that do not require environmental impact statements for most projects. Other such states include neighbors Ohio and West Virginia, which also have encouraged shale gas development.

“I think it is fair to say that states with enforceable requirements to prepare environmental impact statements generally conduct more thorough environmental evaluations than states without such requirements,” Villanova University environmental law professor Todd Aagaard said in an email.

Whether that means those states’ regulations are weaker is difficult to say, he said. Several states that require environmental impact studies are also fairly conservative, including Montana, Indiana and Georgia.

A state agency can still conduct studies of broad environmental issues without such a mandate. The Pennsylvania Department of Environmental Protection has taken on some studies of shale gas’s widespread effects.

It recently completed a statewide study of drilling- and fracking-related radioactive materials. Following litigation with The Times-Tribune, the DEP also began keeping a running list of drilling-tainted water supplies, now up to 258.

Still, it has never prepared a comprehensive environmental impact statement on the subject, as New York has.

In Pennsylvania, the state’s constitutional Environmental Rights Amendment requires balancing environmental harms and benefits, said environment and energy attorney Joel Burcat, partner in Saul Ewing LLP and head of its oil and gas practice.

That 1971 amendment guarantees Pennsylvanians the right to clean air, pure water and the preservation of the environment. Courts have determined it means agencies must consider possible harms in advance when making regulations, he said. One example is a DEP requirement for setbacks from “exceptional value wetlands,” he said.

The Environmental Rights Amendment’s requirements also often come up in appeals, he said, where judges must decide if the DEP’s decisions caused undue environmental harm.

Though a statewide ban on fracking would he hard to justify under the Environmental Rights Amendment, individual well permits could face challenges if it can be shown that there is an adverse impact on natural resources, Mr. Cluck said.

Overall, Pennsylvania has taken a more “optimistic view of the risk-benefit balance,” Mr. Aagaard said. Both New York and Pennsylvania are trying to envision the future with or without a shale gas industry.

“Because predictions are inherently uncertain, it should not be surprising that they would reach different conclusions,” he said.