The latest round of arson-set wildfires in California is a stark reminder of why the F.B.I. has deemed arson as the fastest-growing major crime since the Bureau began including it as an “index crime” in its Uniform Crime Reports.

According to recent statistics, arson is the second leading cause of residential fire deaths. Arson is responsible for 25% of all fires in the United States. It’s estimated that one in four fires is intentionally set and that at least one thousand deaths and three thousand injuries each year result from arson. The number of arson fires annually is believed to exceed one-half million, with almost half involving buildings and other structures, 30 percent involving vehicles, and the balance directed at outdoor targets such as forests. The direct costs of arson in the United States approach $2 billion annually, but estimates suggest that the indirect costs—lost tax revenue and wages, unemployment insurance payments, relocation costs, and other economic ripple effects—are five to ten times higher. Children are responsible for almost half of the arson fires set in the United States.

Because arson is a difficult crime to prove unless there is a confession or a witness—both unlikely, given the nature of the crime and the criminal, it has one of the lowest clearance rates of any major crime. The national clearance rate in 2005 was only 18 percent. Many prosecutors avoid filing formal charges unless the evidence is strong because the conviction rates for arson are low. Also, most insurance companies are reluctant to question claims because they fear civil suits for punitive damages if they turn down a legitimate claim.

Profit is cited in most studies as the primary motive for setting fires. Other motives include vandalism, fraud, revenge, concealment of another crime, and pyromania.

It’s interesting to note that insurance companies are watching to see if the sub-prime mortgage crisis will spur arson by homeowners who face foreclosure. Presently there is no data to show that an increase directly linked to such foreclosures has occurred. ?

In the wake of the wildfires that ravaged Southern California in the fall of 2007, Senator Dianne Feinstein (D-CA) has co-sponsored legislation that would require jurisdictions to establish and maintain arsonist registries and make these registries available on the Internet. Convicted arsonists would be required to register in the jurisdictions in which they reside, are employees or are students. The U.S. Attorney General would be required to maintain a national database at the Bureau of Alcohol, Tobacco, Firearms and Explosives.

Hopefully, this legislation will lead to an increased clearance rate, a decline in the number of arson-set fires, and a significant decrease in annual costs.