NRDC chief: Fracking 'most complicated thing I've encountered'

She explained that fracking presents a double-edged sword of sorts for the environmental community. It’s facilitated a growth in domestic natural gas, which has half the carbon content of coal. But at the same time, Beinecke said, it’s still a carbon fuel.

On top of that, Beinecke said it’s still unclear what fracking might do to public health.

“Our job with fracking is what are the safeguards. What are the science we need to know?” Beinecke said.

On Tuesday, Chevron CEO John Watson called those “legitimate concerns,” saying industry must work harder to self-regulate to earn public trust.

“Public expectations are very high, and there’s no reason they shouldn’t be high. There are some risks out there. Some risks are overstated. But we have to engage them either way,” Watson said at a Washington, D.C., event hosted by the Center for Strategic and International Studies, according to Bloomberg.

Industry contends fracking is safe, noting that states have regulated the practice for decades.

The drilling method injects a high-pressure mixture of water, sand and chemicals into tight-rock formations to access hydrocarbons buried deep underneath.

Energy firms have pushed back against more fracking regulations, such as a draft rule governing fracking on federal lands recently released by the Interior Department.

That rule would establish reporting requirements for disclosing chemicals used in fracking and create guidelines for well integrity and managing so-called flowback water.

Green groups, though, say fracking technology has changed in recent years. They say too little is known about new practices to allow it to expand without proper safeguards and further study, while some want to block fracking altogether.