(Carbon Arc)The father of an Ohio teen who died in 2014 after ingesting a powdered caffeine marketed as a dietary supplement has filed a lawsuit against Amazon.com and the product’s distributors, claiming that they failed to provide proper warnings about the dangers of using the substance. When the 18-year-old died, the amount of caffeine in his system was about 23 times greater than the level in a typical soda or coffee drinker, and a coroner ruled that his death was due to cardiac arrhythmia and seizure due to acute caffeine toxicity. Since then, the Food and Drug Administration has warned people against ingesting pure caffeine, saying that a single teaspoon of the stuff is equivalent to 25 cups of coffee.