Over the last three decades, building materials have changed dramatically. Plumbing, flooring, siding, roofing – most are now made from synthetics. The same goes for the stuff inside the building, like foam rubber seat cushions, plastic computer cases, and nylon carpet fibers. As a result, today’s blazes produce two to three times as much energy as a typical fire did in 1980, and most of that energy emerges as flammable gases. Those gases don’t escape from newer buildings, which are well insulated and tightly sealed. Fires now project their energy much farther from their cores, making them more dangerous and more difficult to extinguish.

Krister Giselsson and Mats Rosander, two Swedish fire engineers, predicted this problem in the late 1970s and began developing new methods to address it. They realized that just approaching the fire – getting close enough to put the wet stuff on the red stuff – was going to be the defining challenge of 21st-century firefighting. —Joshua Davis —The Fire Rebels (Wired)