A harmless symbol of Christmas cheer was once deemed so risky that the FDA had to regulate it. Tinsel once contained lead, which, as scientists realized in the 1960s, made it dangerous to kids. That prompted a deal between the FDA and tinsel makers to alter manufacturing methods, the American Chemical Society reports in a video. The 1972 change was at first kept secret, Popular Science reports, for fear "that many people preferring the lead variety would stockpile it," an official said at the time. Believe it or not, that wasn't the first time tinsel had posed a threat: One reason lead was used is that some kinds of tinsel used to be flammable.
The flammable products came into use amid metal shortages during World War I. Before that, aluminum and copper were often used to make tinsel. These days, it's usually made of plastic, coated with a metal like aluminum. In case you were wondering, our word "tinsel" is derived from the Old French for sparkle, "estincele," and the American version of the holiday tradition likely comes from a German custom of putting silver on a Christmas tree to reflect candle lights. As one maker tells Chemical & Engineering News, tinsel has been quite popular following the Great Recession as an inexpensive decoration method. (There's a good chance your holiday decorations came from this Chinese town.)