PITTSBURGH -- In an unlikely partnership between longtime adversaries, some of the nation's biggest energy companies and environmental groups agreed on a voluntary set of standards for gas and oil production in the Northeast that appear to surpass state and federal pollution regulations.The program announced Wednesday will work a lot like Underwriters Laboratories, which puts its UL seal of approval on electrical appliances that meet its standards. Drilling and pipeline companies are encouraged to independently review their operations, and if they are found to be taking certain steps to protect the air and water, they will receive the blessing of the brand-new Pittsburgh-based Center for Sustainable Shale Development.The move could have far-reaching implications for the industry and environmental groups. A nationwide boom in hydraulic fracturing, or "fracking," has unleashed huge new energy reserves but led to fears of pollution and climate change.Shell Oil Vice President Paul Goodfellow said it's the first time the company and environmental groups have agreed on an entire system for reducing the effects of shale drilling.Bruce Niemeyer, head of Chevron Appalachia, said, "This is a bit of a unique coming-together of a variety of different interests."Besides Shell and Chevron, founding participants include the Environmental Defense Fund, the Clean Air Task Force, the Heinz Endowments, EQT Corp., Consol Energy and the Pennsylvania Environmental Council. Organizers hope to recruit others.This month, industry and environmental groups in Illinois said they cooperated on pending drilling legislation. The Pittsburgh project, in the works nearly two years, is voluntary.The new standards include limits on emissions of methane, a potent greenhouse gas, and the flaring, or burning off, of unwanted gas; reductions in engine emissions; groundwater monitoring and protection; improved well designs; stricter wastewater disposal; the use of less-toxic fracking fluids; and seismic monitoring before drilling begins.The project will cover Pennsylvania, West Virginia and Ohio -- where a frenzy of drilling is under way in the gas-rich Marcellus Shale and Utica Shale -- as well as New York and other states in the East that have put a hold on new drilling.Shell said it hopes to be one of the first companies to volunteer to have its operations in Appalachia independently reviewed. Chevron said it expects to apply for certification, too, when the process is ready to start this year.Mark Brownstein, an associate vice president with the Environmental Defense Fund, said that many companies claim to be leaders in protecting the environment and that "this can be one opportunity for them to demonstrate that leadership" by submitting to an audit.