DENVER – You’ve probably seen the videos on YouTube and on the news: E-cigarette batteries in the pockets of unsuspecting users exploding into showers of sparks and flames.

Doctors, patients and fire officials all say it’s a growing problem that needs to be addressed.

Over the past several weeks, Denver7 Investigates has compiled what we believe to be the most extensive and comprehensive list of e-cigarette explosions in the country. We’ve reviewed information from public records, court filings, internet reports and fire response records.

In Colorado alone last year, there were 16 cases at the University of Colorado Hospital burn center, seven at Swedish Medical Center, two at Denver International Airport, two in Telluride, three in Colorado Springs and one in Greeley. In total, we counted at least 34 e-cigarette battery explosions in Colorado in 2016, with 27 of those cases involving injuries.

Doctors at UCHealth Burn Center say they’ve seen a spike in e-cigarette explosions lately and they’re concerned.

“We didn’t see this two years ago,” said Dr. Arek Wiktor. “We’ve seen a significant increase in these in the past year.”

“We’ve taken care of two patients that were in the process of smoking it when it blew up,” Medical Director Anne Wagner said. “So they ended up with injuries to their face and eyes. It’s a significant problem.” Wiktor and Wagner are the lead surgeons at the burn center, which is the only one in the five-state Rocky Mountain region verified by the American Burn Association.

Denver7 spoke with e-cigarette users Craig Renz, Mike Hapakowski and Greg Ingram. They were among the 16 burn victims treated at UCHealth last year.

Renz said he was walking into a Home Depot store when the e-cigarette in his pocket suddenly exploded.

“I thought I was going to die,” Renz said. “I didn’t know what happened. I thought I’d been shot.”

Craig Renz is seen on surveillance footage moments after an e-cigarette in his pocket exploded.

Ingram and Hapakowski described similar experiences.

“My pants caught fire and the flames shot out and got my thumb, and then I went to pat it out and my whole pocket just erupted,” Ingram said.

Greg Ingram shows the injury to his leg caused by an e-cigarette exploding in his pocket.

“It just happened so fast,” Hapakowski said. “It was literally about a second or two and then ‘POW’ and a full explosion.”

Mike Hapakowski recovers from burns to his leg after an e-cigarette exploded in his pocket.

E-cigarette users say the products don’t come with any kind of warning that the battery could potentially explode.

“I was never told about the dangers,” Renz said. “Had I been told that this had any remote chance of exploding in my pocket the way it did, I never would have bought it. I never would have put it in my pocket.”

A Denver7 Investigates team equipped with hidden cameras randomly visited several Denver-area vape shops. At location after location, managers blamed the powerful batteries and operator error for the explosions, saying users are responsible for more than 90 percent of incidents.

“If you ever see the videos of people with them exploding in their pockets, it’s usually because they took a battery by itself and threw in in the pocket with their keys or spare change,” one manager said.

It’s a claim that Renz finds offensive.

“I wouldn’t walk around with a pipe bomb in my pocket,” Renz said. “Had you told me there was any remote chance this battery could explode while I walk into Home Depot, I certainly would not have purchased it.”

Ingram and Renz both said there was nothing else in their pockets when their batteries exploded.

According to a document obtained by Denver7, not a single e-cigarette explosion was reported to the state’s fire marshal in either 2015 or 2016. Responding to the findings of our investigation, Colorado Fire Marshal Mike Morgan has alerted the National Association of State Fire Marshals, the National Fire Protection Association and the U.S. Fire Administration.

“I think it has the potential to be a really big deal,” Morgan said.

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