Can a firework explode simply by stepping on it?

Some kid had his foot blown off in an explosion in Central Park this morning and the cops are saying he may have "stepped on a discarded firework" while climbing rocks. But that sounds a little iffy to me. I've never heard of a firework exploding when someone stood on it, I thought they had to be lit. Unless of course he created a spark somehow? Perhaps he had a tack in his shoe which sparked when he was climbing the rock, I don't know. But it sounds to me like the kids were looking to set off their own fireworks and disaster struck, now they're denying all knowledge. Time will tell. 
 
That a firework can blow your foot off I can believe. The hoodlum kids in my neighborhood always somehow manage to get hold of a huge stash of those illegal fireworks which literally sound like bombs going off, and the whole month surrounding July 4th sounds like a war zone with long series of very loud bangs sometimes going on all night, and I often think it's only a matter of time before one of them loses a limb. 

It depends on what the explosive is.
 
I remember these things as a kid, which were designed to to pop when pressure is applied:
 
https://en.wikipedia.org/wiki/Bang_snaps
 
 
It's also possible it was just a delayed fuse set by some idiot.

Sounds like they'll accept just anyone into college now-a-days, eh? 

If you wrap a bundle of old fashioned 'sparklers' real tight with duct tape ...

Sounds to me like someone.... maybe the kid, or maybe some other miscreant, deliberately set an IED with a pressure switch, or if it was the kid, things went wrong, and he tried to step on it to stop the fuse but not quite quick enough. 

It really doesn't take a lot of explosive to detach body parts.
 
Most pressure sensitive explosives require much more than the pressure of someone's weight to detonate.  So I think the fuse was lit by the kid and he was trying to put it out or someone was just being evil by leaving an IED for some poor soul to step on by mistake.

I know how to make M-80s but I don't do it because I ALWAYS think bigger and more is better and I surely would end up with an M-360. I think one of those cardboard coin tubes the banks sometimes use would work nicelyThen I'd probably blow a crater into the drainage "pond" (which is always dry) across the street, break some neighbor's windows or something. It's always more fun thinking about things like this than actually doing them, unless of course you're still under 20yo and still immortal and untouchable.
I saw a video yesterday of some guy with a fountain sort of firework, like maybe a foot long, about 4" across at the base and tapered to a point where sparks and fire shoot out of the end that. It looked like a "Hey y'all, watch this" moment. He had his jeans unzipped and unbuttoned and the base stuck in where the zipper is. It all went well, fire and sparks shooting out like he planned until he started his "moves"... then the thing slipped down but stayed in place except it was now pointed up toward his face. It didn't take too long for him to get it out and begin slithering around on the ground like the human snake, lol. It didn't look like he got injured, more like a close call but still... light the fuse and move away. I've seen M-80s blow a mailbox to pieces, saw one blow a metal 3 gallon bucket into small pieces. They would put up a 20' mushroom cloud, they were GREAT toys for kids! I miss cherry bombs too, they would sink when thrown in water (lake) and make a big flash under water. I think people used to fish with dynamite, probably with M-80s too.
I loved playing with M-80s but I never tried to throw one, even I was smarter than that.
 
That thing in the park, who knows. People are a lot meaner and more likely to hurt someone for fun these days. Some things I don't understand. Violence for fun is beyond my ken.
 
J