COLUMBUS, Ohio (AP) - Earthquakes in northeastern Ohio linked to the injection of gas-drilling wastewater into the earth haven't slowed applications for more injection wells.
The Ohio Department of Natural Resources has received 19 applications to drill new disposal wells, in addition to 23 wells already approved but not yet operating.
The agency is reviewing disposal-well applications under a new set of safety standards, including a ban on drilling injection wells into a deep, pre-Cambrian rock formation that geologists consider the source of most Ohio quakes, said Heidi Hetzel-Evans, a DNR spokeswoman.
State regulators said last month a dozen earthquakes were almost certainly induced by injection of gas-drilling wastewater into the earth. There are 171 operating disposal wells statewide.
Planned and proposed wells include five in Mahoning County that would be operated by D&L Energy, the company whose Northstar No. 1 disposal well was linked by the state to 12 earthquakes that rattled Youngstown late last year.
The review includes D&L's proposed wells in Mahoning, which are "well beyond" a 5-mile radius the state drew around the quake zone, said Vince Bevacqua, a D&L spokesman.
Ohio's "class 2" disposal wells take the wastewater, contaminated with salt and heavy metals, that bubbles out of more than 64,400 oil and gas wells in Ohio.
The number of disposal wells began to grow last year with the advent of hydraulic fracturing, the process in which millions of gallons of water, sand and chemicals are injected underground to fracture shale and free trapped oil and gas.
The state estimates that 2,250 Utica wells will be fracked by 2015.
Since the quakes, environmental advocates have focused on disposal wells as a potential threat to public health and safety.
State officials say there hasn't been a single incidence of subsurface groundwater contamination since they took over disposal-well oversight in 1983.