From Marginal Revolution's Alex Tabarrok, see here.
Opponents of hydraulic fracturing often quote the contamination of groundwater as a worthy reason to stop the technique. But, a simple cost-benefit analysis shows that fracking is worth around $100 billion to US consumers and the contamination of groundwater costs around $250 million. In other words, fracking makes more than enough money for the US economy to pay for the contamination it causes 400 times over.
The value to US consumers is certainly greater once you consider that "cleanliness" of natural gas versus other energy sources.
So, frack away.