But Tejada said new plants in the Appalachians could be designed and built to run cleaner and more profitably than older ones in the Gulf, some of which were constructed 50 or even 100 years ago, and updated with costly anti-pollution retrofits over time.
"Every bit of that stuff we don't want someone to breathe is a molecule they can sell. It's a win/win," said of the best designs. He also said that a petrochemical plant produces less pollution over a year than a big coal-fired plant, for example.
"And there are good jobs at these facilities," Tejada said of cracker plants. Ultimately, the environmental impact depends on how well the local authorities enforce whatever laws are on the books, he said.
Shell, which paid $4.7 billion last year for gas rights to about 650,000 acres in the Marcellus region, says it's considering building several specialized types of refineries at a complex. If it builds a cracker refinery, the company would thus be able to supply the plant partly with gas from its own wells, giving it more control over supply and costs.
Currently, most crackers in this country are located in Texas and Louisiana. Experts said it's striking that Shell and other companies are considering building new plants, instead of just expanding existing ones.
"This is very different than building a cracker on the Gulf Coast," said Geoffrey Styles, an energy consultant and former senior planner for Texaco with a widely-read blog. "If you're building a cracker in the Appalachians you have to be absolutely certain that the supply is there. It's a heck of an endorsement of the Marcellus resource."
Hounshell noted that even though there's a lively debate over just how much gas the Marcellus region contains, there's no question it's a huge amount. The U.S. Geological Survey recently dramatically increased its estimate of reserves, from 2 trillion cubic feet to 84 trillion. At almost the same time the Department of Energy lowered its own estimate, saying the USGS figure is more accurate.
"There's no question about it, it's going to be here," Hounshell said of the region. "There's lots of opportunity for them to take cheap gas, and convert it."
A spokesman for Pa.'s Department of Community & Economic Development declined to provide details of negotiations for the plant. A spokesman for the Ohio governor's office also declined to comment.
Burdette, while reluctant to compare and contrast West Virginia and Pennsylvania, said the Mountain State is "a very reliable partner" with a stable, business-friendly environment that is attractive to many industries.
"Our budgets are balanced. There's not any fear of unknown tax increase or tax changes that might impact this," he said Thursday, making a veiled reference to Pennsylvania. "We're actually reducing taxes, not increasing them."
Dennis Yablonsky, CEO of the Allegheny Conference on Community Development, which represents the southwestern part of the state, said he thinks Pennsylvania is competitive.
"I believe that we have sites that work, I believe we have the right work force, I believe we have access to water, so I think we have some of the basic characteristics that are required to make this work," Yablonsky said.
Hounshell noted that with the current economy, Shell is in a very powerful position to play the states off each other, to get the best tax and permitting options.
Shell is also considering building several specialized crackers at a future site, op de Weegh said, to produce chemicals such as polyethylene, used in plastic bags, and ethylene glycol, used in antifreeze.
Bayer said it believes that that the possibility of this new plant in the region shows U.S. manufacturing is at a very significant crossroads.
"We have a few really key advantages over the rest of the world," Iams said. "First, we have the highest productivity of any country. We have a great university network that makes us the most innovative country in the world. With Marcellus Shale, we now have a domestic energy supply that allows us to be competitive on a global level."
Associated Press writers Marc Levy in Harrisburg, Pa.; Vicki Smith in Morgantown, W.Va.; and JoAnne Viviano in Columbus, Ohio, contributed to this report.