Once upon a time, no Christmas tree was complete without a healthy coating of tinsel hanging from the boughs. Those shimmering threads are less common now, though far from gone — especially in households that like an extra touch of sparkly holiday magic. But today’s tinsel, which is usually made of PVC plastic, has a different look and feel than vintage varieties, which were made of real metal. Before you go scouring antique malls looking for a little Christmas cheer, however, know that older tinsel isn’t always better, because sometimes, that metal was lead.

Tinsel made of tin-laminated brass or silver-plated copper began gracing Christmas trees in wealthy American homes in the late 19th century. At the turn of the 20th century, mass production drove the price down and made the decoration accessible to more households. Lyon, France, was a tinsel manufacturing powerhouse, but factories struggled to keep up with U.S. demand due to metal rationing during World War I.

Lead became a popular material for tinsel after a German company received a patent for lead tinsel in 1904, and American companies followed suit. (At the time, the United States was the world’s largest producer and consumer of refined lead.) It remained popular for decades, so much so that tinsel was sometimes referred to as “lead icicles.” Scientists already knew that lead could be toxic, but activism in the 1970s started drawing attention to the hazards the substance posed to children, and the FDA pulled lead tinsel from the market in 1972. Luckily, a Dow Chemical engineer had patented an iridescent plastic tinsel in 1969, so a replacement was already waiting in the wings.

Thomas Edison is known as one of history’s greatest inventors, but he was also a master of marketing. In 1879, Edison’s incandescent bulb was still in its infancy, but the inventor was already vying to bring electricity to the public. In December that year, he made a display of electric lights at his laboratory in Menlo Park, New Jersey, illuminating the property with dozens of his new electric bulbs and inviting the public and press to see. Thousands of people visited the display that winter, dazzled by what the bright future held.

Electricity remained a rarity for most people for several years after that; lighting homes still required open flames, including the precarious use of candles on Christmas trees. But three years after Edison’s first light display, Edward H. Johnson, vice president of the Edison Electric Light Company, gave the public another glimpse of possibility. He wired up a Christmas tree by the window in the parlor of his New York City home with red, white, and blue incandescent bulbs, the first electric Christmas tree lights. 

At first, electric Christmas lights were far too expensive and impractical for most families. Early sets had to be custom wired by electricians, a job that cost around $2,000 in today’s dollars. But Johnson’s stunt drew plenty of attention, just as he and Edison hoped. “I need not tell you that the scintillating evergreen was a pretty sight — one can hardly imagine anything prettier,” the Detroit Post and Tribune raved. 

General Electric began manufacturing preassembled string lights at the turn of the 20th century, and by the mid-1900s, electric Christmas lights had shifted from a luxury to a beloved seasonal tradition.