This story from The Columbus (OH) Dispatch is essential reading. It reports on a study from the Environmental Integrity Project that finds that, despite a federal ban on the use of diesel fuel in hydraulic fracturing without a permit, some oil and gas companies are exploiting a Safe Drinking Water Act loophole to frack with petroleum-based products containing even more dangerous toxic chemicals than diesel - without any permits.
Fracking's Toxic Loophole finds that thanks to what's commonly referred to as the “Halliburton Loophole,” oil and gas producing companies are routinely injecting chemicals more toxic than diesel during hydraulic fracturing operations in at least 11 states. The list does not include Pennsylvania.
While fracking itself has yet to be proven to have contaminated groundwater, faulty wells, leaking impoundments, and spills surely have.
The industry should have enough sense to stop using diesel and petroleum-based chemicals in fracking. But since they apparently don't, the only way to eliminate the risk inherent in using them - both environmental and financial - is to outlaw it. Now. And, while we're at it - if we're really serious - industry practice and regulations must drive to waterless, chemical-free fracking.
October 26, 2014 update: While Pennsylvania was not on EIP's list, it's worth noting that diesel-based drilling fluids are apparently in use - and being spilled - here.