At Home: A Short History of Private Life

by Bill Bryson

Using a flame made from a rich blend of oxygen and alcohol, Gurney could heat a ball of lime no bigger than a child’s marble so efficiently that its light could be seen sixty miles away. The device was successfully put to use in lighthouses, but it was also taken up by theaters. The light not only was perfect and steady but also could be focused into a beam and cast onto selected performers—which is where the phrase in the limelight comes from. The downside was that the intense heat of limelight caused a lot of fires. In one decade in America, more than four hundred theaters burned down. Over the nineteenth century as a whole, nearly ten thousand people were killed in theater fires in Britain, according to a report published in 1899 by William Paul Gerhard, the leading fire authority of the day.

Yikes yikes yikes. Interesting origin of "in the limelight" though.