July 14, 2008 -- The smoke detector industry, tightly controlled by two giants, Kidde and First Alert, doesn't release annual sales figures for the different types of detectors. However, FEMA, the Federal Emergency Management Agency, indicates that by 1991, 88 percent of American homes had at least one detector, and current stats from the National Fire Protection Association put the figure-- thanks to low prices and vigorous campaigns by America's fire officials-- at an astounding 96 percent. But what if most of them don't actually detect smoke when you most need them to? This is a story about ionization detectors, which constitute the bulk of the installed detectors and which can now be readily purchased for less than $5.