The Lorain County Coroner Stephen Evans said Monday that Logan Stiner, 18, ingested too much caffeine powder, which led to the irregular heartbeat and seizures that killed him.
"One sixteenth of a teaspoon has as much caffeine as one Nodoz tablet," Evans said.
One teaspoon of the powder can contain as much as 1,600 milligrams of caffeine. One cup of coffee contains 95 milligrams.
Stiner died days before his graduation from Keystone High School. He planned to study chemical engineering at the University of Toledo.
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