It takes brute force to wrest natural gas from the earth. Millions of gallons of chemical-laden water mixed with sand -- under enough pressure to peel paint from a car -- are pumped into the ground, pulverizing a layer of rock that holds billions of small bubbles of gas.

The chemicals transform the fluid into a frictionless mass that works its way deep into the earth, prying open tiny cracks that can extend thousands of feet. The particles of sand or silicon wedge inside those cracks, holding the earth open just enough to allow the gas to slip by.

Gas drilling is often portrayed as the ultimate win-win in an era of hard choices: a new, 100-year supply of cleaner-burning fuel, a risk-free solution to the nation’s dependence on foreign energy. In the next 10 years, the United States will use the fracturing technology to drill hundreds of thousands of new wells astride cities, rivers and watersheds. Cash-strapped state governments are pining for the revenue and the much-needed jobs that drilling is expected to bring to poor, rural areas.

Drilling companies assert that the destructive forces unleashed by the fracturing process, including the sometimes toxic chemicals that keep the liquid flowing, remain safely sealed as much as a mile or more beneath the earth, far below drinking water sources and the rest of the natural environment.

More than a year of investigation by ProPublica, however, shows that the issues are far less settled than the industry contends, and that hidden environmental costs could cut deeply into the anticipated benefits.

The technique used to extract the gas, known as hydraulic fracturing, has not received the same scientific scrutiny as the processes used for many other energy sources.

For example, it remains unclear how far the tiny fissures that radiate through the bedrock from hydraulic fracturing might reach, or whether they can connect underground passageways or open cracks into groundwater aquifers that could allow the chemical solution to escape into drinking water. It is not certain that the chemicals – some, such as benzene, that are known to cause cancer – are adequately contained by either the well structure beneath the earth or by the people, pipelines and trucks that handle it on the surface. And it is unclear how the voluminous waste the process creates can be disposed of safely.

“This is a field where there is almost no research,” said Geoffrey Thyne, a former professor at the Colorado School of Mines and an environmental engineering consultant for local government officials in Colorado. “It is very much an emerging problem.”

The lack of scientific certainty about hydraulic fracturing can be traced in part to the drilling industry’s success in persuading Congress to leave regulation of the process to the states, which often lack manpower and funding to do complex studies of underground geology. As a consequence, regulations vary wildly across the country and many basic questions remain unanswered.

ProPublica has uncovered more than a thousand reports of water contamination from drilling across the country, some from surface spills and some from seepage underground. In many instances the water is contaminated with compounds found in the fluids used in hydraulic fracturing. ProPublica also found dozens of homes in Ohio, Pennsylvania and Colorado in which gas from drilling had migrated through underground cracks into basements or wells.

But most of these problems have been blamed on peripheral problems that could be associated with hydraulic fracturing – like well failures or leaks – without a rigorous investigation of the entire process.

ProPublica has also found that drilling procedures that can prevent water pollution and sharply reduce toxic air emissions – another frequent side effect -- are seldom required by state regulators and are mostly practiced when and where the industry wishes.

Another uncertainty arises from the enormous amounts of water needed for “fracking.” The government estimates that companies will drill at least 32,000 new gas wells annually by 2012. That could mean more than 100 billion gallons of hazardous fluids will be used and disposed of each year if existing techniques, which often involve 4 million gallons of water per well, are used.

Proposals for new regulations that might prevent many of these problems almost always lead to a fight. And more often than not, that fight devolves into stark, overdrawn choices between turning on the lights or having clean drinking water; getting rich or staying poor.

Energy lobbyists portray skeptics as hysterical and would-be-regulators as over-reaching. Environmentalists cast the dangers as more proven than is the case, and as unsolvable.

In less contentious settings, even the industry acknowledges the lack of science on key issues.

In a conference call with reporters this spring, American Petroleum Institute senior policy advisor Richard Ranger – an industry expert who has spoken frequently on the fracturing issue -- was asked for evidence that fracturing is without environmental risk:

“Have there been any recent studies done on the safety of this?” a reporter asked.

“The issue of where do these fracking fluids go, the answer is based on the geology being drilled,” Ranger said. “You’ve got them trapped somewhere thousands of feet below with the only pathway out being the well bore.

“I’m just not sure that that study is out there,” Ranger said.

“To be clear, we are saying this is a totally safe technology but we can’t point to any recent studies that say this is a safe technology?” the reporter asked.

“Or that says it is unsafe,” Ranger replied.

ProPublica reporters have posed similar questions to more than 40 academic experts, scientists, industry officials, and federal and state regulators. No one has yet provided a more definitive response.

ProPublica’s reporting over the last year points to four looming questions:

Where are the gaps in the environmental science and what will it take to address them?

How will the wastewater be safely disposed of?

Are regulations in place to make sure the gas is extracted as safely as possible?

And are state and federal regulatory agencies equipped to keep up with the pace of drilling?

“Most likely there are not a lot of win-win propositions,” said David Burnett, a scientist at Texas A&M University’s Global Petroleum Research Institute who specializes in industry practices to reduce environmental harm. But, he said, there is opportunity for compromise on enough issues “so that everybody wins sometimes.”

What We Think We Know

Drilling industry officials say they use a slew of engineering techniques – from sonar to magnetic resonance imaging – to study the underground explosions and strictly control the reach of hydraulic fracturing.

They say that the actual fracturing happens thousands of feet from water supplies and below layers of impenetrable rock that seals the world above from what happens down below.

Yet there are reasons for concern. Even if layers of rock can seal water supplies from the layer where fluid is injected, the gas well itself creates an opening in that layer. The well bore is supposed to be surrounded by cement, but often there are large empty pockets or the cement itself cracks under pressure. In many instances, the high pressure of the fluids being injected into the ground has created leaks of gas – and sometimes fluids – into surrounding water supplies.

A recent regional government study in Colorado concluded that the same methane gas tapped by drilling had migrated into dozens of water wells, possibly through natural faults and fissures exacerbated by hydraulic fracturing.

Dennis Coleman, a geologist in Illinois, has seen an example where methane gas has seeped underground for more than seven miles – several times what industry spokespeople say should be possible. He is a leading international expert on molecular testing whose company, Isotech Laboratories, does scientific research for government agencies, pharmaceutical companies, and the oil and gas industry.

“There is no such thing as impossible in terms of migration,” Coleman said. “Like everything else in life it comes down to the probability. It is never a hard and fast thing.”

In another case, benzene, a chemical sometimes found in drilling additives, was discovered throughout a 28-mile long aquifer in Wyoming.

“It is common knowledge that the lower layers are full of irregularities and inconsistencies,” said Patrick Jacobson, a rig worker who manages drilling fluid pumps and has worked on Wyoming drilling projects for more than 20 years. “I think anybody who works in the oil fields, if they tell you the truth, would tell you the same thing.”

Scientists have found it difficult to determine whether hydraulic fracturing is responsible for these problems. In large part that’s because the identities of the chemicals used in the fluids have been tightly held as trade secrets, so scientists don’t know precisely what to look for when they sample polluted streams and taps.

Drilling companies disclose enough information to comply with labor regulations meant to keep workers safe, but that information normally consists of a product trade name and rarely includes a complete list of the chemicals it contains.

Recently, this has begun to change.

In September, New York State – as part of a lengthy environmental review meant to assess the risks of fracturing – made public a comprehensive list of 260 chemicals used in drilling fluids, which it had compiled from disclosures it required drilling companies to make. And several companies themselves have begun to advocate for more disclosure, in the hope that transparency may quell the public outcry that has kept them from drilling in valuable parts of New York State.

Chesapeake Energy, which last year told ProPublica that the chemicals are kept secret because “it is like Coke protecting its syrup formula,” now says that disclosure would bring honest discussion.

“We as an industry need to demystify,” Chesapeake’s CEO, Aubrey McClendon, said at an industry conference in September, “and be very upfront about what we are doing, disclose the chemicals that we are using, search for alternatives to some of the chemicals.”

What is now needed most, according to scientists at the Environmental Protection Agency and elsewhere, is a rigorous scientific study that tracks the fracturing process and attempts to measure its reach into underground water supplies.

In Wyoming EPA scientists with the Superfund program are conducting the first federal investigation of this kind, sampling available water sources and looking for any traces of the chemicals used in drilling. But Colorado’s Thyne says a proper study would go a step further.

“The critical thing that has to be done is a systematic sampling of the background prior to drilling activity, during and after drilling activity,” Thyne said, “Ideally we would go out, we would put monitoring wells in and surround an area that was going to be fractured as part of normal operations. The budget for that kind of project would run ballpark $10 million. It’s a relatively small project for the U.S. Geological Survey or the EPA to undertake.”

Where Should the Waste Go?

On the East coast, one of the most important unanswered questions about drilling is how to dispose of the chemically tainted wastewater that hydraulic fracturing produces.

Most drilling wastewater in other parts of the country is stored in underground injection wells that are regulated by EPA under the Safe Drinking Water Act. However the geology in the East makes injection less viable, and less common. In New York and Pennsylvania, millions of gallons of drilling wastewater could eventually be produced each day.

That wastewater will likely be trucked to treatment plants that don’t routinely test for most of the chemicals the wastewater contains and that may not be equipped to remove them. Currently, the plants also can’t remove the high levels of Total Dissolved Solids found in drilling wastewater – a mixture of salts, metals and minerals – that can increase the salinity of fresh water streams and interfere with the biological treatment process at sewage treatment plants, allowing untreated waste to flow into waterways. High TDS levels also can harm industrial and household equipment and affect the color and taste of water.

After the wastewater passes through the treatment plants it is dumped back into public waterways that supply drinking water to at least 27 million Americans, including residents of Philadelphia and New York City. But without identification and routine testing for the problematic chemicals, it will be impossible to know how much of them are making their way to drinking water sources, or how they are accumulating over time. Evolving medical science says low-dose exposure to some of those chemicals could have much greater health effects than the EPA or doctors have previously thought.

“Managing produced water has always seemed like one of the large challenges, because this area geologically doesn’t have the extensive network of underground injection wells,” said Lee Fuller, vice president of government relations for the Independent Petroleum Association of America. “One challenge that industry has got is looking at developing [treatment] technology, which could be very costly.”

All Equal Under the Law

The gas industry, and hydraulic fracturing, is subject to widely different laws in different states. Some of those laws are tough, perhaps burdening the drilling industry unnecessarily. Others are lenient, perhaps leaving much of the country subject to environmental danger.

One thing is certain: There is no national standard for an industrial process that is used prolifically in 32 states and will be used even more in the future.

Gas drillers receive special exemptions from seven federal environmental regulations that apply to countless other industrial activities across the country.

Drilling companies are not required, for example, to report the discharge of toxic chemicals for the Toxics Release Inventory under the Superfund law – including the wastewater that threatens Eastern water supplies. They do not have to comply with the section of the Clean Water Act that regulates pollutants at construction sites. And they don’t have to abide by the Clean Air Act, which regulates industrial emissions.

Gas drilling also has its own individual exemption, approved by Congress during the George W. Bush administration, that explicitly prohibits the Environmental Protection Agency from regulating hydraulic fracturing under the Safe Drinking Water Act, the way the agency regulates almost all other types of underground fluid injection, including those injection wells used for wastewater in the West.

The argument behind these exceptions is that state regulations sufficiently protect the environment from drilling. But the result is that drilling regulation is left to a patchwork of state laws.

A recent report by the Ground Water Protection Council, a research group that once had energy executives on its board but now consists mainly of state regulators, revealed that only four of the 31 drilling states it surveyed have regulations that directly address hydraulic fracturing and that no state requires companies to track the volume of chemicals left underground. One in five states don’t require that the concrete casing used to contain wells be tested before hydraulic fracturing. And more than half the states allow waste pits that hold toxic fluids from fracturing to intersect with the water table, even though waste pits have been connected to hundreds of cases of water contamination.

Although energy companies have developed many techniques that can reduce the spills and seepages that have occurred across the country, they are usually left to implement them when and if they choose, meaning protections can be entirely different between drilling fields a couple of miles apart.

In northern Pennsylvania, for example, drillers do not have to supply regulators with a complete list detailing every chemical they will pump underground, while 15 miles away, in New York, state authorities have said that such disclosure is a must because it is essential to protecting the water.

Many scientists and members of Congress are arguing for a sturdier national standard that would require minimum environmental protections and ensure that a national energy policy based on natural gas extraction can be pursued without jeopardizing the country’s other natural resources.

“What we’re talking about is just putting some basic parameters around it,” said Rep. Jared Polis, D-Colo. “If companies are able to operate within those parameters… then that’s fine. If they can’t economically do that, then that is because they are causing more damage than they are creating value, and they probably shouldn’t be operating in the first place.”

Polis is one of 50 sponsors of the FRAC Act, a bill before Congress that would restore the EPA’s authority to regulate hydraulic fracturing under the Safe Drinking Water Act and would require the disclosure of the chemical additives.

Congress also recently asked the EPA to conduct a new peer-reviewed study of hydraulic fracturing’s effect on water resources, reassessing its old position.

On Wednesday, the EPA voiced its most explicit concerns in a decade about the environmental risks presented by drilling, in its response to New York State’s plan for drilling in the Marcellus Shale, the layer of rock stretching from central New York to Tennessee. The agency said it had “serious reservations” about whether hydraulic fracturing was safe to do inside the New York City watershed and urged the state to consider possible threats to public health.

EPA scientists have also told ProPublica that the study suggested by Congress may soon be underway. If that research is coupled with a congressional reversal of the exemption from the Safe Drinking Water Act, hydraulic fracturing could eventually be regulated like any other injection well in the U.S. That would require, among other things, thorough testing of the rock miles below the surface to confirm that it can safely contain whatever is injected into it – a stipulation that addresses some of the uncertainty and is inconsistently found in state drilling laws.

EPA regulation “would essentially create a base level,” said Steve Heare, director of the EPA's Drinking Water Protection Division in Washington. Under the Safe Drinking Water Act, states “would basically have to make a showing that their regulations were as effective as ours.”

Better Policing

All the laws and protections in the world won’t ensure that drilling can be done safely if effective enforcement isn’t in place to oversee it.

Yet for all the debate about environmental protections, new laws and national benefits, very little emphasis has been placed on bolstering the agencies that issue drilling permits and go out into the field to make sure the processes are done right.

ProPublica’s recent analysis of 22 states that account for the vast majority of the country’s drilling found that regulatory staffing has not kept up with the drilling boom, meaning that the nation’s ability to enforce rules that provide environmental safeguards is systematically weakening.

New York, one of the hot spots expected to supply this gas-based national energy paradigm, has cut its oil and gas regulatory inspection staff 20 percent since 2003, even while it has approved a 676 percent increase in the number of new wells being drilled each year. Other states have added a few people, but almost none have kept up with the crushing pace of new drilling.

In West Virginia, the third most active gas drilling state in the nation, four new enforcement employees have been hired since 2003, but each inspector is still responsible for some 3,300 wells.

“Crisis management is not the best management in the world and we had to deal with crisis management 90 percent of the time,” said Jerry Tephabock, a former head of state oil and gas inspections in West Virginia who retired in 2007. “There were wells out there that had been drilled that have never been inspected in 15 to 20 years.”

Even if states manage to keep staff levels where they are now – a challenge since 39 states have projected budget deficits for 2010 – the growth that would come from placing more emphasis on natural gas as a part of the nation’s energy strategy may still present sizable risks for both the environment and the economy. Either enforcement would have to slacken, or the permitting of new wells would slow so much that it would stifle the economic growth and energy independence that drilling is expected to bring.

Different states are choosing different paths. Texas regulators promise they will issue new permits to drill within 72 hours, even though their regulator-to-well ratio is one of the most demanding in the nation. New York, in contrast, has pledged to bring new drilling to a crawl until its staff can catch up.

Neither approach addresses the scientific or regulatory gaps that represent drilling’s long-term threats to the environment, however. And it remains to be seen whether politicians and environmental regulators will make sure precautions are taken at the beginning of this new energy boom, or if they will leave the nation to clean up the mess after the boom goes bust, as it has had to do so many times in the past.

ProPublica reporters Joaquin Sapien and Sabrina Shankman contributed to this report.

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