Here's something scary....
 
Deadly Fairfax Fire Shows Growing Peril
By Eric M. WeissWashington Post Staff WriterMonday, July 19, 2004; Page B01

A tiny flame from a candle touched papers that melted vinyl siding and set off a fire that raced unnoticed up three floors. The blaze torched 18 condominiums, left three people dead and forced a man on fire to leap from a third-floor balcony.
Beyond the devastating personal tragedy, the fire in Fairfax County last weekend also highlighted a little-known danger in the Washington region and across the county, fire safety officials say: Houses are built too close together. Radiant heat from the fire in the Kingstowne section of the county nearly set ablaze another building 34 feet away.
"It was about ready to go over there, very close," said Fairfax fire and rescue's Peter J. Michel, lead investigator in the fatal blaze. "I'm surprised we only lost the three the other day."
Michel and other fire officials fear that entire blocks of houses could erupt in flames in a serious fire. National building codes allow single-family houses to be built just six feet apart. Increasing development pressure and the scarcity of land in metropolitan areas are resulting in more -- and larger -- houses built to minimum spacing standards.
Building suburban-style houses at an urban density could cause conflagrations that could devastate whole neighborhoods, fire officials warn.
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I don't have a link to the whole story, but with the trend toward massive density (small lots) and the insistence on building as much house as possible in those little lots, the prospect for major fires is fairly obvious...