Bill Pellan, director of investigations at the Pinellas County Medical Examiner's Office, said the Florida man's death was ruled accidental because the cause of death was a projectile wound to the head.
Tallmadge D'Elia was found dead in his burning bed in St. Petersburg, the Tampa Bay Times reported.
D'Elia, who died on May 5, also suffered burns on almost 80 percent of his body, The Tampa Bay Times reported.
FEMA, a company that routinely keeps statistics on e-cigarettes and other vaping devices, reports that D'Elia's death is the first of its kind in the United States. And in 2016, a vape pen user in NY suffered third-degree burns after the pen exploded in his trousers, NBC 4 NY reported.
A Florida man was killed by an exploding vape pen, authorities say.
A representative from Smok-E Mountain told ABC Action News that their devices do not explode. The medical examiner says the pen was a Smok-E Mountain Mech Works, a type of unregulated mechanical mod e-cigarette, which in an online description says "does not come with safety features".
Gary Wilder told ABC he refuses to sell the devices, fearing they will overheat.
"Make sure that you use the charger that comes with the battery, and make sure the charger has a shutoff device, an automatic shutoff device, so it's not overcharged".
The report blames the incidents on lithium-ion batteries in the products.
The explosion sent two pieces of the vape pen into his cranium, the report said. They include a man losing several teeth and suffering second-degree burns in January 2017 when a vape pen exploded.
The owner of Lizard Juice, an e-cigarette retailer in Florida, said he does not think such vaping pens are "safe enough".
And a vape pen exploded in a man's trousers in 2016 in New York, NBC4 reported.