[ZenGum]

The point of fracking is to create flow in the rock. This means any toxicity has greater potential to spread.

The fracking liquid is not the only source of toxins. Fossil carbon deposits contain all sorts of chemicals, a lot of which you don't want in your ground water. These would also be mobilised by fracking.

Take a long term view. A shale gas field would be productive for what, ten, twenty, thirty years? Contaminated groundwater would remain contaminated for ... centuries? How many jobs, and human lives, depend on that ground water? (Maybe here my Australian view is biasing me - we spend more time drilling for water than for oil, I think. Water is precious. Your view may differ.)

Back to a moratorium. It wouldn't "kill" the industry, just defer it. In a decade, the gas will still be there, and it will probably be worth even more. Brooks' thinking is very much RIGHT NOW, not at all long term.

Check out how the US lead industry for decades fought and suppressed the evidence about how bad lead was for human health. (Try A Short History of Almost Everything, Bill Bryson, quite a fun read). Think about how tobacco companies did the same about cigarettes.
I think people are right to be wary. We are relying for protection on a system that is slow and clumsy at best, and are risking significant long term penalties if this call is wrong.

Fracking IS an efficient and apparently clever way to extract the least-dirty fossil fuel. Provided it can be done without sodding up the groundwater and soil, we might as well. I think we should be more careful to make sure that proviso is being met before calling for full steam ahead. Remember, the companies who are saying we should take the risk are not the ones who will suffer if the risk goes bad. We all know where that can lead - Wall Street.