On a Thursday morning in 1982, a 12-year-old girl in suburban Chicago woke up feeling sick. Her parents decided to keep her home from school and she took a dose of extra-strength Tylenol. Soon after she swallowed the familiar red and blue pills, her parents found her dead on the bathroom floor. Later that afternoon in the nearby suburb, a 27-year-old man felt pain in his muscles. He took a couple of super strong Tylenols and collapsed. When he died that evening, his stunned family gathered at his house. His younger brother took a few Tylenols and then handed the bottle to his wife. Soon they both died.
In the following days, three more women in the Chicago area died after taking extra-strength Tylenol. One of the victims had just given birth to her fourth child and turned to acetaminophen for relief. Another was a single mother raising two small boys. The latest victim was a flight attendant who had just returned to Chicago and stopped at a drug store on her way home to buy the bottle.
First responders immediately felt that Tylenol is the ominous link between the deaths. Authorities collected the suspicious bottles from the grieving families and sent their contents for testing. Laboratory results revealed that many of the pills had been replaced with potassium cyanide tablets. At the time, over-the-counter drugs did not have security seals or tamper-proof packaging. Authorities learned that someone took bottles of Tylenol from store shelves and contaminated them with potassium cyanide before returning them. Five to seven milligrams of potassium cyanide can kill a person, and the pills were much more powerful than 45 mg.
The poisoner was determined to kill, and the toxic tablets were designed to resemble the well-known Tylenol pills. The deadly plan worked, and although authorities still don’t understand the motivation for the murders, they know the culprit chose poison and delivered a dose that no antidote could cure in time. In addition, the shocking murders catalyzed major changes in the way we take pills that still exist today.
Cyanide is a a naturally occurring chemical a compound with a molecular composition of a carbon atom triple bonded to a nitrogen atom. Cyanogenic compounds are produced by various fungi, algae and plants. And some fruit seeds, such as apple seeds, fruit pits and peach pits, contain cyanogenic compounds.
But cyanide can also be produced in several forms, including hydrogen cyanide (HCN), a liquid that is colorless, odorless, and highly flammable. It boils at room temperature and in a gaseous state can kill in a minute. Hydrogen cyanide was used to kill more than one million people in the gas chambers at Auschwitz. Meanwhile, potassium cyanide and sodium cyanide are soluble, ingestible crystals. Potassium cyanide (KCN) was known to be added to flavored punch and then drunk by more than 900 members of the Johnstown cult in a 1978 mass murder-suicide.
Not all uses of cyanide are so nefarious. Cyanides are used industrious for gold mining, pest control, and electroplating, the process of coating a metal with a thin layer of another metal. When used as a murder weapon, however, it doesn’t take long for its devastating effects on the body to set in.
The unknown poisoner in the Tylenol murders used potassium cyanide, which is 10 times more soluble by sodium cyanide. When ingested, potassium cyanide interacts with stomach acids and converted to hydrogen cyanide, allowing it to pass through the cell membrane.
Cyanide disrupts the ability of mitochondria to produce adenosine triphosphate (ATP), which is present in all living tissues and primary source of energy for important bodily functions such as muscle contraction. Without ATP, the central nervous system begins to shut down. Depending on the dosage, symptoms will appear after minutes or hours. At lower doses, a person may first experience headache, dizziness, or nausea before fatal indicators appear. Victims of a larger dose experience more shocking symptoms within minutes, such as arrhythmias, coma or seizures.
Common cyanide poisoning it usually kills from within 45 minutes and most victims go into cardiac arrest. This means that victims are usually already off treatment by the time they arrive at the hospital, and doctors must rely on an autopsy to find out what killed the patient.
The emergency room doctors who saw the three family members poisoned by the contaminated Tylenol noticed that they all had dilated pupils, an indication of brain damage. After lab results confirmed the pills were poisonous, authorities moved quickly to warn the public. News warned people to throw away all Tylenol products. The manufacturer of Tylenol voluntarily download all products across the country and offered a reward for information leading to the capture of the unknown assailant.
However, the authorities never learned who did the poisoning or how they did it. They suspected that the poisoner did not work in a manufacturing facility, but instead took advantage of the fact that retail products at the time did not have protective seals or tamper-proof packaging.
It didn’t take long for the Food and Drug Administration to respond, quickly mobilizing efforts to stop deadly manipulations in the future. Tamper-proof packaging became mandatoryand the following year the US Congress passed an act making it a federal crime tamper with consumer products. The pharmaceutical industry also moved away from capsules because they were easier to contaminate than tablets.
Such safety measures remain important, but concern over cyanide has shifted to something else in the last few decades. The US government considers cyanide a potential agent of chemical terrorism to contaminate food and water supplies. In 2019, an article in Journal of Medical Toxicology warned that cyanide was the “perfect chemical weapon” because it was readily available and easy to use. Most worryingly, it is also very deadly.