Forty years ago, when North Carolina banned using deep wells to permanently dump industrial waste, some thought the issue had been decided for good. Now state lawmakers who want to turn North Carolina into the nation’s next fracking hotspot are reopening the case for injecting brines and toxins deep underground.
This time, the proposal is shifting the fracking debate from the center of the state, where the energy exploration and economic benefits would occur, to tourism-dependent coastal communities where the disposal wells would have to be drilled.
“That’s where it would be – no doubt about it,” said Rep. Rick Catlin, a Republican from Wilmington who is a hydrogeologist and environmental engineer. “It’s going to be very controversial.”
Fracking removes natural gas trapped in prehistoric shale rock formations by pumping in water and chemicals to smash the rock – a process that creates tons of waste.
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The proposal’s impact on the coast is not widely known because the bill in the state legislature doesn’t specify where the fracking waste would be injected. Many lawmakers assume the injection wells, which can accept waste for years from multiple fracking operations, would be located near the fracking sites.
Now it’s becoming clear that coastal residents and businesses could also be affected if fracking gets under way several hundred miles inland. The legislation, which is a signal to the oil-and-gas industry that North Carolina is eager to host shale gas exploration activities, would also lift the state’s fracking moratorium in March 2015.
The bill has sailed through the state Senate and is now before the House, where it is likely to be assigned to the Public Utilities Committee. The chairman of the committee, Rep. Mike Hager, said the implications of lifting the waste disposal ban are so far-reaching they raise serious doubts and will require further study.
“What does it do to the community that doesn’t get the revenue from the natural gas production?” asked Hager, a Republican from western Burke and Rutherford counties. “We will have to look at how these communities are compensated.”
Bill sponsor Sen. E.S. “Buck” Newton said the concerns may be premature. He said such injections are an accepted method of disposal and have been successfully done hundreds of thousands of times in the United States.
“I really don’t see it as an issue,” said Newton, a Republican representing Johnston, Nash and Wilson counties. “We’re talking about putting water into a deep area that already has that kind of water.
“All my information is that the best way to deal with these runs that come up is to reinject it,” he said. “If it went from County A to County B, I’m not sure why County B would have a major objection to that.”
Other options complicated
Deep injection into wells is the industry’s preferred method of getting rid of fracking waste and is approved by the federal Environmental Protection Agency. The other options are much more expensive and logistically complicated. They include trucking the fluids to municipal water treatment plants, which are increasingly rejecting fracking residues, or using open-air evaporation in large impoundments.
Injection wells are not immune from spills and accidents, but they may be best known for their linkage to earth tremors where fluid is stored and pressurized underground near faults. The concerns in this state include aquifer damage below, as well as potential property damage on the surface.
“You’re basically contaminating an aquifer forever,” Catlin said. “Please don’t inject any down here.”
The state’s environmental agency, in a 484-page report published last year on the risks and benefits of shale gas exploration, urged against legalizing deep disposal of fracking wastes. The report by the N.C. Department of Environment and Natural Resources focused on the risks to deep storage in Lee, Moore and Chatham counties, where the energy exploration is most likely to take place.
The underground geology west of Raleigh is not porous enough to absorb fluids, forcing the pressurized injections to seek fissures and faults, said Tyler Clark, the N.C. state geologist from 2002 to 2006.
What’s more, the rock is blasted throughout with magma sheets called diabase dikes, which serve as the region’s natural plumbing system and lead water to freshwater aquifers.
“One you put it in the ground, it’s not going to stay there, it’s going to go somewhere,” Clark said. “It would be hard to predict where it could travel.”
Hundreds of these magma sheets break up the rock, often protruding on the surface. Geological maps show that some dikes run for several miles, and parts of Lee County have as many as 10 dike intrusions per mile.
Eastern N.C. geology
DENR concluded that the dikes permeating the state’s midsection make fracking itself problematic because the dikes could transmit fracking fluids – a mixture of water and chemicals – to underground drinking sources.
The geology in Eastern North Carolina, however, is unlike the rest of the state. It contains saline aquifers separated by layers of clay, a layer cake formation in some areas reaching 10,000 feet deep to the bedrock. The saline aquifers could potentially accept the waste injections because they are highly absorbent, said retired UNC-Wilmington geology professor Paul Thayer, who has worked for BP, Amoco, Chevron and Mobil.
But Thayer added that it would require comprehensive studies and analysis to prove the area could accept the waste without spreading.
The coastal aquifers have been used just once for chemical injection in the only such deep injection site permitted in the state’s history.
Those wells, about four miles from Wilmington, were created by Hercules, a company that manufactured the raw materials used in the production of polyester fabrics. Hercules began injecting acids in 1968 at a rate of 300,000 gallons a day and continued pumping through 1972.
The wells, set between 850 and 1,050 feet deep, clogged and leached chemicals into a sand, gravel and limestone aquifer. Monitoring wells in upper aquifers later showed that the chemicals traveled past a clay containment zone and contaminated upper aquifers.
That underwater leakage led to the state’s ban on deep injection wells. Modern well construction standards and other advances would make such an accident less likely today, but many will not want to take the risk.
Rep. Catlin said some of the coastal aquifers have low salinity and could potentially be tapped as drinking water sources if desalination plants are built. Furthermore, he said the barriers between the aquifers are not watertight, as the Hercules accident exposed.