Those of us who were around in the 1960s remember the revelation that smoking causes cancer—how it mounted slowly year after year, until it became irrefutable. This gradual increase in the evidence was due to the time required to study large populations of people over a period of many years.
It seems that fracking is headed in the same direction. As fracking expanded over the last decade from relatively unpopulated areas in the Midwest into the eastern states, (e.g., Pennsylvania), the data sets grew to the point we find ourselves now, i.e., knowledge that fracking is almost certainly connected with premature births, increased risk of asthma, as well as a combination of migraine headaches, chronic nasal and sinus symptoms, and severe fatigue.
The latest report, which came from researchers at Johns Hopkins University, has put the fracking industry in the same situation that the tobacco companies faced way back when: vigorously denying all ill-effects from their trade.
Of course, the fossil fuel industry is no stranger to this type of denial, as we learned earlier this year when it became clear that executives at ExxonMobil conspired—over a period of 35 years–to hide the truth about the connection between oil consumption and climate change. All that practice has made these folks and their squadrons of attorneys quite adept at telling this story.