nullIn Centralia, Pennsylvania, clouds of smoke and toxins from a 48-year-old coal mine fire
waft past empty fields and abandoned homes.

Glen B. Stracher

Not far from Hazard, Kentucky, in the shadow of Lost Mountain, a woman named Ruth Mullins saw smoke rising off the slope. “I knew it wasn’t no woods on fire, because of the smell”—the rotten-egg stench of sulfur—she said. Her suspicions were soon confirmed: Lost Mountain’s coal mine, abandoned for 40 years, was burning. 

Kentucky names coal fires for the people who first report them, so the fire, which has continued to smolder and occasionally flame since it was identified in 2007, is known officially as the Ruth Mullins fire. “We’ve never met the woman and we don’t know where she lives, but her name now appears in scientific publications that are read all over the world,” says Jennifer O’Keefe, a geologist at Kentucky’s Morehead State University. “She’s got her little bit of immortality.” 

O’Keefe is part of a team that has been visiting the Ruth Mullins fire over the past three years, studying its behavior and quantifying the gases that plume from nine known openings in the ground. Last January she and a colleague, University of Kentucky geologist James Hower, brought some students to the coal fire for new measurements. They parked off Highway 80, a road that cuts a swath along the side of Lost Mountain, and unloaded gear in a stingingly cold wind as speeding trucks whipped ice along the asphalt. Trudging up the snow-covered mountain, the scientists shivered along the flat shelf of land circling its midsection, the remains of contour mining in the 1950s. While smoke from the burning mine had been hard to spot from the road, here it billowed from small vents where portals to the mine had collapsed.


Approaching the site, all except Hower (who stayed farther back) donned pink respirators. A student equipped with a GPS device tried to detect the outline of the underground fire by looking for areas where the snow was thinner or melted away entirely. Two other students and O’Keefe settled at a vent, measuring the temperature at the opening and the velocity of the gases (including carbon monoxide, carbon dioxide, hydrogen sulfide, methane, and oxygen) that were flowing out.

“Jen, do we have any tar or minerals up there?” Hower called to O’Keefe, who shook her head. He made his way care­fully over some fallen trees, possibly killed by the coal fire cooking their roots, to another vent and climbed closer, sliding a little in the snowmelt and mud made warm by the mine’s hot breath. Here there was plenty of tar and minerals: Black goo two-toned the leaves on the ground, and minerals that had precipitated out of the gases encrusted the tree roots dangling over the vents. To identify the potentially dozens of hydrocarbon gases roiling beneath, he stuck a tube deep inside each vent, collecting emissions in a steel canister for later analysis in a laboratory at the University of California at Irvine.

Hower also retrieved a weathered contraption perched at the entrance to one of the vents. Cobbled together from galvanized-steel stovepipes and heat-resistant tape, this assemblage, nicknamed the Tin Man, had been taking measurements for 22 days. Three layers of filters impregnated with activated carbon captured mercury emissions, and a pair of instruments recorded temperature and carbon monoxide every 10 seconds for three days. Another set of devices monitored the same parameters every minute for the entire duration. Through these measurements, the team will gain a better understanding of the long-term variation in the fire’s temperature and emissions.

This was the second Tin Man. The first, deployed during a 2009 study, showed that the carbon monoxide level at Ruth Mullins dropped dramatically once a day and then shot back up again. “These mine fires seem to have a regular breathing cycle,” Hower says.

Coal fires are as ancient and as widely distributed as coal itself. People have reported fires in coal beds close to the earth’s surface for thousands of years—in fact, Australia’s Burning Mountain, once thought to be a volcano, sits atop a coal seam that has been on fire for some six millennia. But ever since the Industrial Revolution, the number of coal fires has grown dramatically. There are now thousands of such fires around the world, in every country—from France to South Africa to Borneo to China—where mining exposes coal deposits.

These fires are an insidious, persistent, and often nearly invisible threat to local health and to the natural and built environment. Added to that, there is now a growing realization that all these coal fires together may contribute significantly to climate change, a risk that has inspired the United States Geological Survey (USGS) to measure emissions of greenhouse gases (pdf) and other pollutants from coal fires around the United States, starting with three in the Powder River Basin of Wyoming. The USGS effort, including scientists from organizations around the country, was convened to employ new tools and expertise to measure greenhouse gases from coal fires, which have not been included in previous national and worldwide surveys. “What is the overall contribution of these coal fires to global warming?” asks Glenn Stracher, a geologist at East Georgia College whose work inspired the USGS effort. “That’s an important question that no one has answered, and that’s why this team of scientists has gotten together to work on a quantitative analysis.”

Most Americans are unaware of these long-burning coal fires, with the possible exception of the mine fire in Centralia, Pennsylvania. In 1962 residents of this small mining town burned trash in an abandoned strip mine used as a dump near the Odd Fellows Cemetery, not realizing that the mine had not been properly sealed. The trash was reduced to smoldering piles, which firefighters later extinguished—or so they thought. But the fire continued to burn, and a month later bulldozers arrived for a more concerted effort to put it out. The citizens then discovered that the dump contained a 15-foot-long opening that connected to a maze of underground mine tunnels. These passages allowed the fire to spread to the coal seam underneath the town and expand along four fronts, eventually affecting a surface area about two miles long and three-quarters of a mile wide.

Since then, around $4 million has been spent to put the Centralia fire out, to no avail. It continues to burn today, moving through a vast network of abandoned mines that are still littered and lined with coal. No one knows how extensive these empty spaces are, and the effort to quell the blaze has come to an end. “It’s too expensive to tackle, and we’re not sure we can do it anyway,” says Alfred Whitehouse, chief of the Reclamation Support Division of the federal Office of Surface Mining.