The science of fire

Great story about how scientists have been figuring out what really happens when a building burns, and why so much arson “evidence” is bunk:

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.”

The good news is that genuine science is starting to be used by fire investigators. The bad news is that it’s a slow process, and there is still much resistance from the old guard and certain political quarters, as we have clearly seen in Texas, though perhaps the closing of the Willingham case, which included an agreement from the Fire Marshall to review old cases where bunk science might have played a role in getting a conviction, will help change that. They’ll have their choice of cases to investigate, as the unfortunate consequence of all this is that there’s a lot of people who have been convicted of deliberately starting what were surely accidental fires.

In Massachusetts, the percentage of building fires determined to be arson has dropped from more than 15 percent in the early 1990s to less than 2 percent in 2009. In Texas the proportion of fires labeled incendiary has declined by more than half in the last decade. Nationwide, according to the National Fire Prevention Association, the number of intentional structure fires declined by about 51 percent between 1990 and 2007, the most recent year for which statistics are available—from 111,900 incidents to 54,700.

There aren’t fewer fires, there are fewer fires being incorrectly classified as crimes. Even these shrunken numbers are likely too high, and the trend is of no comfort to those wrongly rotting in jail. It’s a real tragedy.

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