Abandoned gas wells — essentially deep holes in Earth’s crust that slowly spit out methane — will soon be capped in one of Tennessee’s federally-protected lands. 

The U.S. Department of the Interior announced funding Thursday to plug orphaned oil and gas wells in national parks, forests, wildlife refuges and other public lands and waters. 

In Tennessee, the department will remediate five gas wells in the Big South Fork National River and Recreational Area, a protected 125,000 acres in the Cumberland Plateau that includes both the Big South Fork National River and the Cumberland River. 

“Decades of drilling have left behind thousands of non-producing wells that now threaten the health and wellbeing of our communities, our lands, and our waters,” Department of the Interior Secretary Deb Haaland said in a statement.

The five gas wells in the Big South Fork area were drilled in the 1980s, according to the National Park Service. The average gas drill depth during that time was about a mile below the surface, but wells can be much deeper.

The total number of abandoned oil and gas wells in the U.S. are known to be undercounted, with some estimates in the hundreds of thousands. The Environmental Defense Fund mapped 120,000 orphaned wells across the nation. There’s a high concentration in southern Kentucky that spills into Tennessee. There are at least 300 orphaned wells in the state, according to the EDF. 

Courtesy Environmental Defense Fund

Last year, the Environmental Defense Fund mapped 120,000 orphaned oil and gas wells, which are fossil fuel extraction sites that lack monitoring or owner responsibility.

The Department of the Interior defines “orphan wells” as the holes left behind after extractive companies abandon site use, monitoring and responsibility, similar to how many coal companies, with promises of reclamation, have caused significant environmental harm yet escaped accountability for it. 

The main threat is methane leaks. Methane is a greenhouse gas that is roughly 80 times more potent than carbon dioxide at heating the planet over a 20-year timeframe.

Oil and gas drilling sites account for some of the world’s worst climate pollution sites. Texas’ Permian Basin and the Ohio-West Virginia area’s Marcellus Shale, which likely feeds methane through pipelines to gas plants in Tennessee, are currently ranked first and fourth, according to Climate Trace.  

Leaking gas wells can also pollute air and drinking water sources, and they have been found under backyards, sidewalks, houses and apartment buildings. 

Tennessee has as many as 16,000 oil and gas wells, based on the number of permits granted by the Tennessee Department of Environment and Conservation since 1968, but there is limited information on their activity or closure status. 

The $64 million funding announced Thursday comes from a $16 billion investment from the Biden Administration’s Bipartisan Infrastructure Law to address legacy pollution.