"Drillers use a flare when they don't have a pipeline ready -- during exploration or expedited drilling -- or when they haven't paid for equipment to separate gas from the large amounts of water that rise along with a well's initial gush. Drillers often need to test an area's resources before investing in pipelines, or don't want to plug a well to wait for the pipeline because of the risk that water could ruin the well, said Andrew Paterson, a technical expert at the industry group Marcellus Shale Coalition.
Drillers do now have the technology to separate water from gas at the well site and other equipment to capture stray gas from tanks and valves there. That led environmental advocates to push for mandates.
The Environmental Protection Agency will continue to allow flaring at exploratory wells -- where the expense of a pipeline connection may not be justified -- but drillers will have to capture what is now flared or allowed to vent from tanks by 2015."