Nearly a year ago, residents of New Freeport, Pennsylvania, a little town about 70 miles south of Pittsburgh, learned about one of the many dangers of abandoned oil and gas wells the hard way. 

Tom Bussoletti, a stonemason who lives just outside of town, said several witnesses told him that liquid began gushing “15 feet into the air” from an abandoned well at the bottom of Fox Hill—one of at least 699 abandoned, unplugged wells in Greene County. 

The Pennsylvania Department of Environmental Protection is still investigating the incident, but the agency has said that the abandoned well was “communicating” with a new, deeper gas well owned by EQT Corp. a mile away. That well was being fracked, a process that involves forcing millions of gallons of water through horizontal pipes to release natural gas trapped in ancient shale formations. Fracking fluid contains toxic chemicals and picks up other dangerous substances as it gushes through the shale.  

One of the known risks of abandoned wells, many of which were drilled before there were good regulations or records, is that fracking fluid can find an underground path to them and then spew to the surface. The wells, which often just look like pipes sticking from the ground, also can release methane, a potent greenhouse gas, and other chemicals that can be harmful to people, plants, and wildlife. 

Because of Pennsylvania’s long history as a source of oil and gas—the nation’s first oil well was drilled in the state in 1859—it is now pockmarked with abandoned wells. Estimates for how many there are vary wildly. While some are as high as 560,000, DEP thinks that 250,000 is a more likely total. So far, it has identified 27,449 orphaned wells—wells that have no owners—and has plugged another 3,346 of them. Many of the wells were abandoned before the government began requiring owners to plug them with cement. Early owners often just walked away when the wells stopped making money. 

Estimates put the number of abandoned wells in the United States at more than 3 million.  

Under the Bipartisan Infrastructure Law, Congress set aside $4.7 billion in 2021 to plug abandoned wells. That money started flowing to states last year. Pennsylvania has received $25 million and is on track to get another $375 million, said Neil Shader, DEP’s director of communications.

“It seems like a lot of money, but it is woefully inadequate to address this whole issue,” Seth Shonkoff, an environmental scientist who is executive director of PSE Healthy Energy, said of the federal funding.  

“I have a hard time believing that this problem will ever be completely fixed,” he said, “but I think that it is quite clear that we can make decisions on which wells to fix first and which wells really matter, and that will help to blunt the impact on human health and the environment.” 

Soon after the incident with the abandoned well in New Freeport, residents noticed that their well water looked dirty and felt greasy. Some developed rashes after contact with it. Animals refused to drink it. Plants watered with it wilted. For months, the Center for Coalfield Justice in Washington, Pennsylvania, brought in bottled water for people afraid to drink the water at home. 

Michael Widdup, who works as an electrician in the oil and gas industry, was renovating his home in New Freeport about 200 feet from the abandoned well when he heard about the water gushing from the abandoned well, which some call a “frac-out.” He’d been living elsewhere while he fixed his house. When he checked his water, “it was dirty and slimy and had a film on it,” he said. The water is less slimy now, but it still looks dirty, and it has elevated lead, which he suspects came from pipes in the old well.

He plans to haul in water when he moves back home. While some in the community have started drinking their well water again, others have invested in expensive filtration systems or are buying water. 

“It’s a financial burden,” he said. 

News of the water problems also has depressed housing values, making it harder for people to leave, he said. “My Zillow on my house has dropped a hundred thousand dollars,” he said. 

EQT has “adopted” the abandoned well and plans to plug it properly. Tests of residents’ wells “have not shown impacts connected to EQT’s operations” and it has not yet concluded that communication between the two wells occurred, a spokeswoman said.

John Stolz, director of the Center for Environmental Research and Education at Duquesne University, also tested local well water. His tests found methane, light hydrocarbons, and evidence of brine—salty water found in rock formations that contain oil and gas—in some wells. Two wells had methane levels of 14 milligrams per liter. At 28 mg per liter, it would have been flammable, Stolz said.  

“It was clear that the fracking had induced a change in the water table and the quality of water in wells,” he said. 

How could the state lose track of so many wells? The answer is that many were drilled in remote locations in an era when no one was required to report where they were. In many cases, drillers left open pipes that are now obscured by vegetation.  

More dangerously, some are now under parking lots or buildings. Some may just look like small depressions in the ground. “You’re actually lucky if there’s any steel pipe sticking out of the ground,” said David Yoxtheimer, a Penn State hydrogeologist. During World War II, salvagers harvested old well casings to build war machinery. 

These abandoned wells are what the industry calls “conventional”—wells that extracted oil and gas through straight vertical pipes pushed into certain rock formations. The “unconventional” wells drilled during the fracking boom are still producing gas, so plugging is not yet a problem. They have long horizontal pipes that access natural gas in the Marcellus shale formation. They will be harder to plug, but their owners are on the hook to do the work. Both types of wells can use treated water to increase production, a process that also increases potential pollution. 

It might seem that pouring cement down a hole would be a relatively inexpensive project, but Shader said the cost of plugging usually ranges from $10,000 to $200,000. It can go much higher. Pennsylvania may be able to save some money by plugging groups of nearby wells at the same time. It prioritizes wells that pose the greatest health and environmental risks.  

Yoxtheimer said filling wells is often costly because remote wells are so hard to access. And the cement must reach the bottom of the well, which can be anywhere from 2,000 to 10,000 feet deep and hard to find. If a well is next to the foundation of a house, the work gets very tricky.  

While methane usually is not toxic, it is explosive and flammable.  

When you buy natural gas for your house, it comes with a chemical that adds its distinctive scent. In its wild form, natural gas or methane has no odor unless it happens to contain hydrogen sulfide, a dangerous gas that smells like rotten eggs. There may be nothing to alert a property owner to gas collecting on his land or in his basement. “Oftentimes, you don’t realize it until it’s too late,” Yoxtheimer said.   

Bussoletti said his water was not affected by the EQT’s fracking, but he knows of another abandoned well on a neighbor’s property that began “perking methane” after the incident. He says that well is 200 feet from a propane pipeline. What would happen, he wondered, if lightning struck the abandoned well and started a fire?

Aside from fire risk, abandoned wells can damage air, soil and water quality, and have economic consequences.  

As the danger of global warming has become more apparent, methane leaking from these wells has gotten more attention. Mary Kang, a professor of civil engineering at McGill University who has studied emissions in Pennsylvania and Canada, said the global warming potential of methane is 86 times higher than carbon dioxide’s over a 20-year period and 34 times greater over a century. In short, reducing methane emissions can produce faster results. 

In her Pennsylvania work, she found that some abandoned wells produce more methane than others, a fact that could help guide plugging efforts. Gas wells were worse than old oil wells and some wells, even those that had been plugged, in coal country were high emitters. 

In a 2016 study, she estimated that abandoned wells contributed 5 to 8 percent of methane emissions caused by human activity in Pennsylvania. 

Joshua Axelrod, senior advocate at the Natural Resources Defense Council, said that abandoned wells are one of the top 10 sources of methane in the U.S. and Canada. Attacking this “low hanging fruit” is an “obvious choice,” he said. “You have to go after every source.”  

Kang cautioned, though, that the amount of methane escaping from the top of a well doesn’t tell scientists what’s happening below ground. Because wells pass through aquifers, contamination of water and soil could be happening below the surface even in wells that aren’t emitting a lot of methane.   

“If you care about groundwater and broad environmental impact, it’s way murkier,” she said. “… There’s a lot we fundamentally don’t know about it.” 

Yoxtheimer said that fluids inside abandoned wells, which could contaminate groundwater or soil around a well head, can contain barium, strontium, radioactive radium, benzene and toluene. Arsenic and hydrogen sulfide are also common, Axelrod said. 

A study published in May confirmed for the first time that some wells are also releasing benzene, a toxic chemical often present in natural gas, with the methane. This is important because methane released into the air is a global warming problem, but not necessarily an immediate local problem, said Shonkoff, one of the study authors. Benzene is a carcinogen, and it adds to the dangers of abandoned wells near where people live. 

The study found only that benzene was present at significant levels. More work will be needed, Shonkoff said, to determine whether the amount of benzene is dangerous to people breathing air nearby. 

“We certainly identified that these wells are a human health hazard,” he said. 

Research by Jeremy Weber, an economist at the University of Pittsburgh who teaches in the graduate school of public and international affairs, lends credence to Widdup’s view that abandoned wells affect land value. In a study of a western Pennsylvania county published last year, his team found that there was half as much building over a 50-year period in the two acres surrounding unplugged wells as in the two acres around plugged wells. In addition, foregone investment had depressed property values by 12 percent.  

“What we’re finding is that it is in fact important that these wells get plugged so that alternative uses of land can happen,” Weber said. 

Often government is the only hope for plugging the oldest wells, because the original drillers are long gone, or more recent owners have gone bankrupt. 

“Pennsylvania’s definitely a national leader in the number of wells for which there’s no financially responsible party,” he said. 

While drillers now must promise to plug their wells when they stop producing, several experts said the state does not make them set aside enough bond money to do that and has trouble enforcing the rules when owners ignore them. 

Weber thinks the state needs to charge more upfront and increase fines and penalties. “It will make some wells uneconomical to drill,” he said, “and I would argue that that just reveals that you don’t want those wells drilled in the first place.” Wells should not be drilled if the only way that makes financial sense is to shift the future cost of plugging to taxpayers, he said.

DEP has reported that more than 2,200 wells were abandoned between 2017 and 2021, said David Hess, a former DEP secretary who now writes an environmental blog.  He agrees with Weber that the state needs the resources to get tough with recalcitrant owners or filling old wells won’t do much good. “These conventional operators,” he said, “have made abandonment of their wells part of their business plans.”