Seven people in and around Chicago died in the autumn of 1982 after taking Tylenol capsules that someone had emptied and refilled with potassium cyanide. The first was a twelve-year-old girl in Elk Grove Village, who took one for a sore throat before school. Three members of one family died within two days of each other. They were not connected by anything except the bottles in their homes.
What linked the cases was ordinary attention. A pharmacist noticed the same product turning up. Two off-duty investigators, comparing notes about separate deaths, realised they were describing the same capsule. The recall followed, and so did the foil seal and the glued carton and the plastic band on the neck of the bottle, which is why opening a new packet of paracetamol still takes a moment of effort. The person responsible was never identified.
The foil seal on the bottle mouth goes on without anything touching it: a coil above the cap induces a current in the aluminium, the heat melts a polymer layer and bonds it to the glass or plastic rim. It was already a known packaging method in 1982, and within months it was on shelves everywhere.