We're going to turn to our consumer watchdog report tonight and that new trend, those indoor parks with wall-to-wall trampolines and a staggering number this evening. About 100,000 are injured on... See More
We're going to turn to our consumer watchdog report tonight and that new trend, those indoor parks with wall-to-wall trampolines and a staggering number this evening. About 100,000 are injured on trampolines indoors and outdoors each year. Here's elisabeth leamy telling us why they're not safe. Reporter: Trampoline parks have never been more popular. Leaping from just 1 in 2009 to more than 50 across the country today, but they can be dangerous. These youtube videos show chilling accidents leading to severe injuries, even death. 30-year-old ty thomason of phoenix died after breaking his neck diving into one of these foam pits at a trampoline park. That's an example of the problems with them. Poor design because the foam in the pits may not be thick enough and poor maintenance if the foam gets matted down from overuse. Another risk, say critics, poor supervision. I could tell that this is the worst birthday I've ever had. Reporter:5-year-old eliana huffing of chicago broke her leg after a bigger girl jumped on her trampoline causing her to fall. Experts say multiple kids should never jump on the same trampoline, but not all parks enforce that rule. Three other children came off crying because they got hurt at the same time, so it angers me a lot that it's so common. Reporter: Common enough that seattle lawyer, simeon osborn, has 20 cases pending against trampoline parks. 'S no certain code that they have to follow, any regulations they have to follow, so they can do pretty much whatever they want. Reporter: When we visited a trampoline park, we had to sign a wordy two-page waiver promising not to sue if we were hurt or killed. This video shot by a concerned dad shows a trampoline park where broken springs stick out. The trampoline industry cites federal statistics that show far more children are injured on bicycles and skateboards than on trampolines, but the american academy of pediatric s considers recreational trampolines so dangerous that it says children should never play on them, period. Elisabeth leamy, abc news, washington.
This transcript has been automatically generated and may not be 100% accurate.