“The only thing that can cause that to react is an accelerant,” Vasquez said. Hurst was incredulous. A natural-wood fire can reach temperatures as high as two thousand degrees Fahrenheit—far hotter than the melting point for aluminum alloys, which ranges from a thousand to twelve hundred degrees. And, like many other investigators, Vasquez and Fogg mistakenly assumed that wood charring beneath the aluminum threshold was evidence that, as Vasquez put it, “a liquid accelerant flowed underneath and burned.” Hurst had conducted myriad experiments showing that such charring was caused simply by the aluminum conducting so much heat. In fact, when liquid accelerant is poured under a threshold a fire will extinguish, because of a lack of oxygen. (Other scientists had reached the same conclusion.) “Liquid accelerants can no more burn under an aluminum threshold than can grease burn in a skillet even with a loose-fitting lid,” Hurst declared in his report on the Willingham case.
Hurst then examined Fogg and Vasquez’s claim that the “brown stains” on Willingham’s front porch were evidence of “liquid accelerant,” which had not had time to soak into the concrete. Hurst had previously performed a test in his garage, in which he poured charcoal-lighter fluid on the concrete floor, and lit it. When the fire went out, there were no brown stains, only smudges of soot. Hurst had run the same experiment many times, with different kinds of liquid accelerants, and the result was always the same. Brown stains were common in fires; they were usually composed of rust or gunk from charred debris that had mixed with water from fire hoses.
Another crucial piece of evidence implicating Willingham was the “crazed glass” that Vasquez had attributed to the rapid heating from a fire fuelled with liquid accelerant. Yet, in November of 1991, a team of fire investigators had inspected fifty houses in the hills of Oakland, California, which had been ravaged by brush fires. In a dozen houses, the investigators discovered crazed glass, even though a liquid accelerant had not been used. Most of these houses were on the outskirts of the blaze, where firefighters had shot streams of water; as the investigators later wrote in a published study, they theorized that the fracturing had been induced by rapid cooling, rather than by sudden heating—thermal shock had caused the glass to contract so quickly that it settled disjointedly. The investigators then tested this hypothesis in a laboratory. When they heated glass, nothing happened. But each time they applied water to the heated glass the intricate patterns appeared. Hurst had seen the same phenomenon when he had blowtorched and cooled glass during his research at Cambridge. In his report, Hurst wrote that Vasquez and Fogg’s notion of crazed glass was no more than an “old wives’ tale.”
Hurst then confronted some of the most devastating arson evidence against Willingham: the burn trailer, the pour patterns and puddle configurations, the V-shape and other burn marks indicating that the fire had multiple points of origin, the burning underneath the children’s beds. There was also the positive test for mineral spirits by the front door, and Willingham’s seemingly implausible story that he had run out of the house without burning his bare feet.
As Hurst read through more of the files, he noticed that Willingham and his neighbors had described the windows in the front of the house suddenly exploding and flames roaring forth. It was then that Hurst thought of the legendary Lime Street Fire, one of the most pivotal in the history of arson investigation.
On the evening of October 15, 1990, a thirty-five-year-old man named Gerald Wayne Lewis was found standing in front of his house on Lime Street in Jacksonville, Florida, holding his three-year-old son. His two-story wood-frame home was engulfed in flames. By the time the fire had been extinguished, six people were dead, including Lewis’s wife. Lewis said that he had rescued his son but was unable to get to the others, who were upstairs.
When fire investigators examined the scene, they found the classic signs of arson: low burns along the walls and floors, pour patterns and puddle configurations, and a burn trailer running from the living room into the hallway. Lewis claimed that the fire had started accidentally, on a couch in the living room—his son had been playing with matches. But a V-shaped pattern by one of the doors suggested that the fire had originated elsewhere. Some witnesses told authorities that Lewis seemed too calm during the fire and had never tried to get help. According to the
Subsequent tests, however, revealed that the laboratory identification of gasoline was wrong. Moreover, a local news television camera had captured Lewis in a clearly agitated state at the scene of the fire, and investigators discovered that at one point he had jumped in front of a moving car, asking the driver to call the Fire Department.
Seeking to bolster their theory of the crime, prosecutors turned to John Lentini, the fire expert, and John DeHaan, another leading investigator and textbook author. Despite some of the weaknesses of the case, Lentini told me that, given the classic burn patterns and puddle configurations in the house, he was sure that Lewis had set the fire: “I was prepared to testify and send this guy to Old Sparky”—the electric chair.
To discover the truth, the investigators, with the backing of the prosecution, decided to conduct an elaborate experiment and re-create the fire scene. Local officials gave the investigators permission to use a condemned house next to Lewis’s home, which was about to be torn down. The two houses were virtually identical, and the investigators refurbished the condemned one with the same kind of carpeting, curtains, and furniture that had been in Lewis’s home. The scientists also wired the building with heat and gas sensors that could withstand fire. The cost of the experiment came to twenty thousand dollars. Without using liquid accelerant, Lentini and DeHaan set the couch in the living room on fire, expecting that the experiment would demonstrate that Lewis’s version of events was implausible.
The investigators watched as the fire quickly consumed the couch, sending upward a plume of smoke that hit the ceiling and spread outward, creating a thick layer of hot gases overhead—an efficient radiator of heat. Within three minutes, this cloud, absorbing more gases from the fire below, was banking down the walls and filling the living room. As the cloud approached the floor, its temperature rose, in some areas, to more than eleven hundred degrees Fahrenheit. Suddenly, the entire room exploded in flames, as the radiant heat ignited every piece of furniture, every curtain, every possible fuel source, even the carpeting. The windows shattered.
The fire had reached what is called “flashover”—the point at which radiant heat causes a fire in a room to become a room on fire. Arson investigators knew about the concept of flashover, but it was widely believed to take much longer to occur, especially without a liquid accelerant. From a single fuel source—a couch—the room had reached flashover in four and a half minutes.
Because all the furniture in the living room had ignited, the blaze went from a fuel-controlled fire to a ventilation-controlled fire—or what scientists call “post-flashover.” During post-flashover, the path of the fire depends on new sources of oxygen, from an open door or window. One of the fire investigators, who had been standing by an open door in the living room, escaped moments before the oxygen-starved fire roared out of the room into the hallway—a fireball that caused the corridor to go quickly into flashover as well, propelling the fire out the front door and onto the porch.
After the fire was extinguished, the investigators inspected the hallway and living room. On the floor were irregularly shaped burn patterns that perfectly resembled pour patterns and puddle configurations. It turned out that these classic signs of arson can also appear on their own, after flashover. With the naked eye, it is impossible to distinguish between the pour patterns and puddle configurations caused by an accelerant and those caused naturally by post-flashover. The only reliable way to tell the difference is to take samples from the burn patterns and test them in a laboratory for the presence of flammable or combustible liquids.
During the Lime Street experiment, other things happened that were supposed to occur only in a fire fuelled by liquid accelerant: charring along the base of the walls and doorways, and burning under furniture. There was also a V-shaped pattern by the living-room doorway, far from where the fire had started on the couch. In a small fire, a V-shaped burn mark may pinpoint where a fire began, but during post-flashover these patterns can occur repeatedly, when various objects ignite.
One of the investigators muttered that they had just helped prove the defense’s case. Given the reasonable doubt raised by the experiment, the charges against Lewis were soon dropped. The Lime Street experiment had demolished prevailing notions about fire behavior. Subsequent tests by scientists showed that, during post- flashover, burning under beds and furniture was common, entire doors were consumed, and aluminum thresholds melted.
John Lentini says of the Lime Street Fire, “This was my epiphany. I almost sent a man to die based on
