This year’s fear of rainbow fentanyl in kids’ trick-or-treat bags is just the latest unfounded Halloween candy freakout. But the yearly panic has its roots in a very real crisis: the 1982 Tylenol murders.

This episode was produced by Avishay Artsy, edited by Matt Collette, fact-checked by Laura Bullard with help from Jillian Weinberger, engineered by Efim Shapiro, and hosted by Sean Rameswaram.

Transcript at vox.com/todayexplained

Support Today, Explained by making a financial contribution to Vox! bit.ly/givepodcasts

Learn more about your ad choices. Visit podcastchoices.com/adchoices