Updated November 18, 2021

Fact checked by Elizabeth MacLennan

Coal mine fires in Columbia County, Pennsylvania, first ignited in 1962.

The Centralia fire has been burning through an abandoned deep mine in Pennsylvania’s Buck Mountain Coal Bed since May of 1962.

State officials aren’t entirely sure how the blaze started, but the most widely accepted theory is that the fire was set by local personnel to reduce the volume of trash in a municipal waste disposal area.1 Apparently, the intentional controlled burn got out of hand and jumped to an abandoned, 75-foot wide by 50-foot deep surface mine that had been left open when it was excavated in 1935 (coal mining history in the area goes back to the 1840s).2

Due to a poorly conducted shale barrier intended to keep combustible materials out of the mine, the fire spread quickly throughout the underground coal mine system and hasn’t stopped since.

History of the Centralia Fire

Between 1962 and 1978, state and federal governments spent $3.3 million on measures to control the fire, which were mostly unsuccessful. By 1983, the United States Office of Surface Mining had determined that it would take an estimated $663 million to extinguish the fire completely.3

Due to concerns about bushfires and toxic fumes, US Congress approved $42 million to relocate businesses and residences impacted by the fire a year later; 545 were moved between 1985 and 1991.3

Meanwhile, nearby Route 61 suffered enough damage from the underground fire to be closed indefinitely in 1993. A section of the highway went on to earn the nickname “graffiti highway,” becoming a local legend of sorts and unofficial tourist attraction, despite being deemed dangerous. The road is constantly subsiding, cracking, and spewing fumes to this day.

The Pennsylvania Department of Environmental Protection “strongly discourages anyone from visiting the immediate area” due to the dangerous gases present and ground prone to sudden and unexpected collapse. They also warn that walking or driving in the area could “result in serious injury or death.”2

Do People Still Live in Centralia?

According to U.S. Census Bureau data, as of 2020 only 10 residents lived in the 155-acre borough, now considered a “ghost town” (the town doesn’t even have an official zip code anymore).4

When the fire first started, Centralia was home to between 1,100 and 1,200 people.1

Why Hasn’t It Been Put Out?

While experts believe that the fire could be extinguished eventually, the time and cost of such a project would be beyond the capacity of the Pennsylvania Abandoned Mine Lands Program. Likewise, the price for excavating the mine fire would require an equally long and expensive project, while flooding the entire fire could risk a catastrophic mine blowout and collapse that the government feels isn’t worth the risk.

According to the Department of Environmental Protection, there isn’t one entity held liable for the fire. However, the state does conduct monthly visual surface monitoring on the fire’s temperature and location.

As of 2012, the fire involved about 400 surface acres and was growing an average of 50 to 75 feet per year for the past 50 years. Temperatures range from 900 degrees Fahrenheit to up to 1,350 degrees Fahrenheit depending on the fire’s proximity to the surface (the state also estimates that there were approximately 25 million tons of coal in the main coal vein beneath Centralia when mining first began in the 1840s).1

View of a sulfur dioxide detection tube held over a capped borehole in Centralia, Pennsylvania, in June, 1981.

Gas monitoring, on the other hand, is only done “in response to special circumstances.” State agencies monitor the fire using a series of over 2,000 boreholes that have been drilled into the mine fire area to help locate and control the fire.1

Environmental Impact of the Centralia Fire

The main environmental concerns surrounding the Centralia fire are air pollution, greenhouse gas emissions, and vegetation die-off due to the ground’s excessive heat—which can also create brush fires.

Just as is the case with most human-derived disturbances to natural environmental systems, coal mine fires have the potential to impact multiple generations of organisms within multiple ecosystems, sometimes even beyond the point of recovery.

According to a study published in the journal of the International Society for Microbial Ecology, soil samples taken from the area around the Centralia fire were severely altered by elevated temperatures and coal combustion deposits, and recovered to display more resilience to fire conditions only after a period of 10 to 20 years (and only after the main stressors subsided). Elements like ammonium and nitrate were elevated at the active fire vent sites. During the time it takes for the soil community dynamics to recover, however, the researchers found decreased composition diversity and changes in pH.5

Extreme soil heat has been shown to reduce plant photosynthesis and negatively affect root development by altering the rate at which water can move from the soil into the root and plant system.6

It's possible that climate change could also make the fire more dangerous. After central Pennsylvania saw its wettest year on record in 2011 (185 centimeters, nearly twice the annual average) thanks to Hurricane Irene and Tropical Storm Lee, scientists recorded the formation of nine new sinkholes between 1.8 meters and 26 meters (5.9-85 feet) in size over the Centralia fire. The rain had filtered through the soil and hot bedrock underneath, allowing steam and other gases to escape through surface exhaust vents and cave in.7

Abandoned mine drainage—water that is polluted by coal mining activity—can create highly acidic water that’s rich in heavy metals and sulfur-bearing minerals. The resulting polluted drainage can be extremely toxic and mix with groundwater, surface water, or soil, having harmful effects on animals and plants.8

As for carbon emissions, it’s estimated that underground coal fires generate as much as 3% of the world’s total annual CO2 emissions while consuming 5% of the planet’s mineable coal.9

Underground Coal Fires

While the Centralia fire has certainly received the most publicity, the phenomenon of underground fires isn’t exactly unheard of. In fact, there are 241 known coal mine fires currently burning across the United States, 38 of which are in Pennsylvania.1

In Jhaia, India, a series of coal mine fires have been burning since 1916, consuming about 40 million tons of coal and leaving 1.5 billion tons inaccessible. Researchers estimate that, if the fire continues to move at the current rate, the flames will persist for another 3,800 years.10

In New South Wales, Australia, the oldest known coal seam fire in the world has been burning for 5,500 years at Mount Wingen (otherwise known as Burning Mountain). The fire burns 98 feet below the ground’s surface and has moved at a rate of 1 meter (3.2 feet) per year since it was first discovered in 1829.11