More than 500 companies are already involved in shale natural gas drilling in southwestern Pennsylvania, and the economic effects extend to many unrelated industries, according to the Pittsburgh Regional Alliance. "I look at it not as a boom, but it will for over a century be an integrated part of our economy. I think boom implies bust, and I think what we are seeing is a new entrance into our region's economy," said Kathryn Klaber, CEO of the Marcellus Shale Coalition.