PHILADELPHIA — A major conference on shale gas opened here today with former Pennsylvania Gov. and industry consultant Tom Ridge calling for an “energy revolution” that will help release the United States from the “vice grip of our dependence on foreign oil.”

Ridge says the U.S. needs to rely on natural gas and other homegrown sources of energy, calling it vital to national security. He says many of the concerns about the environmental and public health impacts of drilling are “phony hysteria.”

John Pinkerton, CEO of drilling company Range Resources, followed Ridge at the Pennsylvania Convention Center. He says the industry needs to develop a “more robust market” for natural gas.

Drilling opponents are holding a march and rally to counter the industry event.