A recent opinion piece missed some key facts on hydraulic fracturing, injection wells and induced seismicity in Oklahoma ("Fracking may be inducing earthquakes," July 1).
Hydraulic fracturing is a well-regulated process that has been used more than 1.2 million times in the United States. According to the National Academy of Sciences, hydraulic fracturing "does not pose a high risk for inducing felt seismic events."
Wastewater injection is a separate process used to dispose of wastewater from an array of industries from oil and gas to manufacturing and agriculture. While the process has been linked to some seismic events, the National Academy of Sciences put it best, saying that "very few events have been documented over the past several decades relative to the large number of disposal wells in operation."
As for Oklahoma, a recent report suggests that only four injection wells of the 4,500 in the state were linked to seismic activity. This echoes numerous other findings that the risk for seismicity associated with injection wells is actually quite low.
On that point, Bill Ellsworth of the U.S. Geological Survey has said the problem has "been fixed by either shutting down the offending well or reducing the volume that's being produced. So there are really straight-forward fixes to the problem when earthquakes begin to occur."
However, any impacts should be addressed and that's why the oil and gas industry continues to work with experts and regulators to assure the continued safety of its operations. It is important the public has access to the facts.
Dana Bohan, Washington, D.C.
The writer is a staffer at Energy In Depth, an education and outreach arm of the Independent Petroleum Association of America.