Why Is It So Easy to Slip Someone Antifreeze?

Last week Texas oncologist Ana Maria Gonzalez-Angulo was charged with aggravated assault after attempting to poison her lover and fellow doctor George Blumenschein with ethylene glycol—the toxic main ingredient of antifreeze—that she slipped into his coffee. Plenty of other people have used similar plots for murder, and the most recent Annual Report of the American Association of Poison Control Centers counted 6241 unintentional ethylene glycol poisonings in 2011. Why don’t any of these people realize they’re eating poison?

To his credit, Dr. Blumenschein appears to be one person who did notice something was off. He normally took his coffee black, but noticed that the cup Gonzalez-Angulo served him was sweet. When he asked for a different one, but she insisted he finish the one he’d been given and that she’d just put a little Splenda in it. This helps illustrate why antifreeze poisoning is so common and often successful: Ethylene glycol tastes pretty good for something that can kill you.

Ethylene glycol is syrupy, odorless, and sweet-tasting, which makes it easy to mix into coffee, tea, soda, and juice drinks undetected. Even in accidental exposures where the toxin isn’t masked by other flavors, the sweet taste doesn’t set off any alarm bells the way other, bitter toxins do, and people and pets may not notice anything is wrong.

The toxin primarily affects the nervous system and the kidneys, causing headaches, slurred speech, dizziness, nausea and—as the body metabolizes it into other toxins—potentially fatal kidney dysfunction and failure. A dose of around a third of a cup can be lethal.

To help prevent ethylene glycol poisonings, some states require that ingredients be added to antifreeze to make it bitter-tasting and unpalatable. Last year a number of antifreeze and automotive coolant makers agreed to voluntarily add bittering agents to their products even where not required by law. Once the new, grosser products hit the shelves, would-be murderers will have to go back to the drawing board and find another yummy poison (unless they can get pure ethylene glycol, often used in labs like Gonzalez-Angulo’s). In the meantime, I wonder if this case will inspire copycat crimes, like those the Georgia Poison Center saw after the high-profile ethylene glycol poisoning of a police officer and the televised trial of his wife.