By Kim Palmer
CLEVELAND (Reuters) - Ohio has suspended operations at five deep wells used to dispose of fracking-related fluids after nearly a dozen earthquakes in the town of Youngstown over the past year, the latest sign of local unease over the booming shale gas industry.
One day after a 4.0 quake, the Ohio Department of Natural Resources said on Sunday it was halting operations at five Mahoning County wells owned by Northstar Disposal Services LLC as a precaution, citing concerns of a possible link between well activity and the quakes. The wells were used to store wastewater from oil and gas drilling operations, not for production.
"We are being overly cautious in order to ensure public safety in asking the company to halt disposal injections at one site on Friday and then asking for a halt to any injections in a 5-mile radius Saturday," Ohio Department of Natural Resources deputy director Andy Ware said.
"Our geologist would say there is a strong chance there is a fault line very close to the site of the well," Ware said, adding the department was concerned that pressure from the fluid disposal could be affecting a previously unknown fault line.
Ohio's decision comes amid an intensifying debate about the environmental impact of hydraulic fracturing, the process of extracting oil or natural gas from shale rocks by drilling miles deep wells and injecting thousands of gallons of water to flush out natural gas deposits trapped in between its layers.
While much of the focus has been on the risk that toxic fluids may contaminate drinking water, local fears about low-level seismic activity have also grown.
Early last year, an area of Arkansas experienced a series of small earthquakes which were said to have been linked to injecting wastewater underground as a byproduct of gas drilling. In July, the Arkansas Oil and Gas Commission voted to ban wells for the disposal of natural gas drilling fluids in the area.
Shale gas drilling in the northwest United Kingdom also caused a couple of earthquakes in April and May, energy company Cuadrilla Resources said in November.
Ohio Governor John Kasich felt the move was important to "quickly ensure the safety of the public," spokesman Robert Nichols said.
"We fully expect to be criticized for overreacting on this, but we are OK with that," Nichols said.
TREMORS OVER SHALE BOOM
The discovery of underground gas deposits and development of technology to release the gas has led to an unprecedented boom of production in the United States, boosting output to a near 40-year high and driving prices to lows.
But the risk of new regulations tied to concerns over its impact on the environment threaten to cloud the future of reserves that may provide decades' worth of supply.
Geologists say it is possible for drilling to cause tremors in the earth though it depends on how close a company drills, or in this case, injects wastewater, near a fault line.
Earthquakes induced by human activity have been documented in a few locations in the United States, Japan and Canada, according to the U.S. Geological Survey website. The largest and best known resulted from fluid injection at the Rocky Mountain Arsenal near Denver, Colorado, where in 1967 a 5.5 magnitude earthquake followed a series of smaller quakes.
Ware said Northstar began drilling in mid-summer. The injection disposal started in December 2010 and the first earthquake occurred in 2011. A representative for Northstar could not be reached for comment on Sunday.
Earthquakes are not common in Youngstown, and seismic records going back to 1980 show no reports of earthquakes prior to the series of quakes last year. A 2.1 magnitude quake, the first of 11 in 2011, was reported on March 17. More were reported in August, September, October, November and December.
Ware said after a 2.7 magnitude quake was reported on December 24, Northstar voluntarily lowered the pressure at one well.
On Saturday a 4.0 earthquake was reported, "causing the Ohio Department of Resources to recommend all wells in the area stop operations," Ware said.
After the initial spate of earthquakes in the area, four more monitors were set up near the first well to get more data on the source of the seismic activity.
There are 177 disposal wells currently in operation in Ohio. The Mahoning County well is 9,000 feet/ deep and is used to dispose of hazardous fluids, injecting fluid that cannot be disposed of in landfills into sandstone well below groundwater level.
Ware could not say when or if the wells would resume operations. Authorities said there may be a change in how the wells operate.
"That is one of the things that would be discussed, possibly plugging the well to a certain level." Ware said. "We will continue to monitor and have our geologists monitor the data."
(Writing and reporting by Kim Palmer; Additional reporting by Jeanine Prezioso; Editing by Mary Wisniewski, Cynthia Johnston, Bill Trott and Andrew Hay)