Gregory Gorbett/Eastern Kentucky University

Also see the related article, "Seven Myths About Arson."

On a rainy spring morning in eastern Kentucky, Greg Gorbett prepares to commit arson. His target is a tidy but cheerless one-bedroom apartment with the kind of mauve-colored carpet, couches, tables, and lamps you would find in a cheap motel. Gorbett is not the only one eager to see the place burn. A handful of other fire scientists and grad students from Eastern Kentucky University (EKU) are checking equipment in the test room as well. They have gathered at the EKU fire lab, a concrete structure in an open meadow as close to nowhere as possible, to document in exacting detail the life cycle of a blaze.

Gorbett scans the setup one last time. A foil-covered wire studded with metal probes—a thermocouple array—crosses the ceiling and hangs down the center of the space; it will measure the temperature at one-foot intervals every two seconds. A radiometer shaped like a soup can will detect changes in radiant energy. Bundles of yellow wires will carry the data to a computer-equipped truck sitting out back. There is also a man lying on the floor: James Pharr, a former fire investigator from Charlotte, North Carolina, wearing a fire-resistant suit and oxygen mask, who will record the event with a thermal-
imaging camera.


Gorbett lights a pan of flammable heptane under an end table and then quickly exits the room. The fire begins as a glowing ball and then reaches up and curls around the tabletop like a claw. Quickly it moves to the adjacent couch, which bursts into flames. Modern cushions are made of polyurethane foam, and despite their fire resistant–covering (introduced in the 1970s to protect against smoldering cigarettes), they are basically solidified petroleum. A modern couch can release the heat equivalent of a 3 million watt lightbulb.

The fire doesn’t burn the couch so much as melt it, like a marshmallow over a campfire. Flaming liquid drips onto the floor, forming fiery puddles, some of which burn through the carpet. Pharr squiggles out of the room, dragging his camera. Curtains drop burning fragments that in turn start their own flames. The couch across the room catches fire, although no other source of fire has touched it. “Radiant heat,” Gorbett explains.

Bill Hicks, monitoring the fire on his computer in the truck, is calling out temperatures over the walkie-talkie. “Five ninety,” he says, reading the measurement at the ceiling in degrees Celsius. That translates to almost 1100 degrees Fahrenheit. The room is obscured by a layer of roiling black smoke. A lightbulb pops. The carpet catches fire. The window cracks. “Better get back,” Gorbett says, and we retreat from the window. The smoke layer descends like a curtain almost to the floor. “Seven sixty at the ceiling,” calls Hicks. Fourteen hundred Fahrenheit. The radiometer spikes.

“Flashover!” yells Hicks.

A furious orange flame explodes out the window and door. The room has gone from being the scene of a fire to being completely on fire. Everything has ignited—carpet, furniture, combustible vapors. A few minutes later, a crew of firemen move in to extinguish it.

Afterward Gorbett and his colleagues walk through the rubble, take photos of the burned furniture and walls, measure the depth of charring, tabulate the results, and compare them to other trials in the experiment. They are not alone. At laboratories throughout the United States—some large enough to contain a three-story house—researchers have been lighting rooms and houses on fire and analyzing the results with the kind of scientific scrutiny that has upended several deeply entrenched misconceptions about how fires behave. The upheaval is more than academic. For generations, arson inspectors have used outmoded theories to help indict and incarcerate many suspects. But as new science is brought to bear on old cases, it is becoming clear that over the past several decades, dozens, perhaps hundreds, of people have been convicted of arson based on scant research and misguided beliefs. Many of those people are still in jail, hoping that someone will take up their cause.

“A lot of bad science has been applied to arson investigation,” says John Lentini, a renowned fire expert who has given exculpatory testimony in at least 40 arson cases since 2000. His most recent case, now under review, involves a Massachusetts man convicted of arson by Molotov cocktail, even though not a single glass fragment from the supposed bottle bomb was found at the scene.

“I shudder to think how many wrongful convictions there are,” says Richard Roby, president and technical director of Combustion Science and Engineering, a fire-
protection engineering firm based in Columbia, Maryland. Roby has testified for several men charged with arson. One, named Michael Ledford, could not have been 
at the scene when the fire that killed his son was allegedly set, according to Roby’s calculations, yet he is now serving a 50-year sentence. “It’s amazing to think how long it takes for basic science to be accepted,” Roby says. “I lose sleep over this every week.”