How loud does something have to be to kill someone? I heard once on BattleBots that it took 150 decibels to stop the human heart. Is this true? If so, I’m afraid, since I work in a VERY loud job environment (I assemble 747 engines). So is there a fatal decibel level? And if so, is it really 150 decibels? Please tell me. I’m scared.
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What we’re talking about here is high-energy-impulse noise, also known as blast overpressure or air blast, which is “the sharp instantaneous rise in ambient atmospheric pressure resulting from explosive detonation or firing of weapons” (N.M. Elsayed, “Toxicology of Blast Overpressure,” Toxicology, 1997). What, you say this isn’t noise in the usual sense? Nonsense. It’s no different from a thunderclap or a sonic boom. It’s true you might not hear a truly titanic air blast, but that’s because your eardrums would shatter, and worst case you’d be dead.
The lethal effects of air blast first became evident during World War I, when soldiers were found dead in the vicinity of an explosion despite having no external injuries. There was plenty of internal damage, though, particularly to hollow organs such as the ear, lung, and gastrointestinal tract. Partly for that reason the exact cause of death due to air blast has been debated for many years. The prevailing theory at the moment is air embolism originating in the lungs. The blast’s immense pressure on the chest ruptures delicate lung tissue, admitting air bubbles into the arteries that travel to the heart, brain, and other organs and cause sudden death.
Art accompanying story in printed newspaper (not available in this archive): illustration/Slug Signorino.
