By now, the general public knows what fracking is: An extractive operation that injects water, chemicals and sand down through drill-holes under high pressure and blasts oil or natural gas out of porous rock.

Fracking isn’t new, but it’s more expensive and potentially more damaging to the environment than conventional drilling, so it wasn’t commonly used in the US until the last decade, as demand for domestic oil and gas ballooned and extraction technologies advanced.

The types of layered, porous rock that yield oil and gas are called shales: Specifically, carbonaceous (black) shales.

Fracking started in shales out West, and fracking for oil is still done out there, but fracking for gas has shifted eastward, notably to the Marcellus Shale, a very large geologic formation stretching northeast-southwest along the Appalachian Mountains across New York, Pennsylvania, Ohio, and West Virginia.

Marcellus fracking has been most extensive in Pennsylvania so far, close enough for Connecticut environmentalists to wonder if it might come here.

According to state geologist Margaret Thomas, Connecticut does have black shale. It was laid down during the Mesozoic Era, from 250 to 65 million years ago, when Connecticut’s climate was tropical, the oceans were warm, and dinosaurs flourished.

Our shale beds, known collectively as the Hartford Basin, run from shorelines near New Haven north through Connecticut roughly along the I-91 corridor, extending through Massachusetts almost to Vermont.

Any red rock visible near the highway may host shale, but the shale beds are not continuous throughout the basin, and where they do appear they’re thin: Thick, rich beds may measure several hundreds of feet, the ones here at most only one or two. Thus, the Hartford Basin would not be profitable to frack for gas under any plausible economic scenario.

That matter laid to rest, environmentalists have a related worry: Contaminated water. One to six million gallons of water are needed to frack a typical gas well. Of that, up to two percent consists of chemicals to facilitate production, many of them toxic, and the fluid picks up even more pollutants down amid the shale, such as salt brines and naturally occurring radioactive materials

The brew causes trouble enough underground, but…fast forward…what happens when it’s brought back up through the drill-pipe and needs disposal?  This is the most important question and least studied of any about fracking, experts acknowledge.

The bottom line for Connecticut, though, is that answers are needed before any contaminated water gets disposed here, so that protective regulations can be put in place.

“Apply the precautionary principle,” say environmentalists. “Bar the door.”

This does look like a classic case. One legislative proposal environmentalists have put forward is HB6533, prohibiting “the treatment, discharge, disposal or storage of [fracking] waste in the state.”

It’s been approved by the Energy and Technology Committee

While it’s being debated further, a second installment of “Hot Air” will examine more closely the questions about how to manage fracking wastewater—and also review some answers.