Cuba has denied what would be an unprecedented breach of obligation to protect foreign diplomats, and not to blast them with acoustic energy. But exposure to sound waves would be a plausible explanation for this constellation of vague symptoms unified by a relationship to the inner ear.

It is indeed possible to weaponize energy waves with frequencies outside the range that the human ear can detect. The concept is not new, and it has a rich history in science fiction. Weaponization of sound was a plot point in the book that Secretary Tillerson has called his favorite, Ayn Rand’s 1957 novel Atlas Shrugged. In it, the federal science institute creates a weapon of mass destruction which deploys ultrasonic waves. The head of state uses the device to flatten a goat in a demonstration of power, and later to destroy the work of industrious private inventors, successfully stifling private-sector innovation.

The health effects of exposure to inaudible sonic waves are also real. In 2001 after residents of Kokomo, Indiana, began reporting symptoms including “annoyance, sleep disturbance, headaches, and nausea,” the U.S. National Institutes of Health investigated the issue. The result was a dossier on the toxicology of “infrasound”—acoustic energy with wavelengths of 17 meters or more. The agency couldn’t pin down the cause of the Indiana residents’ symptoms as infrasound, but the report did confirm that infrasound can cause fatigue, apathy, hearing loss, confusion, and disorientation. In one study cited therein, volunteers exposed to industrial infrasound for just 15 minutes reported fatigue, depression, pressure in the ears, loss of concentration, drowsiness, and “vibration of internal organs.”

While infrasound would seem to be a possible and plausible mechanism of the “health attacks” in Cuba, CNN has also reported that some incidents were accompanied by audible noises—“deafeningly loud sound similar to the buzzing created by insects or metal scraping across a floor.” The mechanism in that case would be less subtle. Deafeningly loud sound is so called because it either ruptures the eardrum or jolts the tiny bones of the middle ear.

At the same time, CNN also posits, “The sophistication of the attack has led U.S. officials to suspect a third country is involved, perhaps seeking payback against the United States and Canada or to drive a wedge between those countries and Cuba,” raising the possibility of operatives from Russia, China, North Korea, Venezuela, or Iran.

It's not clear why these attacks would qualify as sophisticated. Noise-induced hearing loss affects around one in four people—only, usually, it’s due to lower-level exposures over years, from attending concerts, shooting guns, and being too cool to cover one’s ears when an ambulance screams past on the street. While the investigation in Havana unfolds, fascination with this sort of attack can be a reminder that it is worth arming ourselves in daily life against the more quotidian forms of sonic weaponry.