Kids these days don't know what hazardous fireworks are... why, back in my day, when we walked six miles to school uphill both ways, fireworks were dangerous. I mean real dangerous, like the M80s we used to by all the time. How dangerous were they?

Federal law now caps the flash powder content of firecrackers at 50mg per firework. Typical M-80s contained somewhere in the neighborhood of 3,000mg of powder apiece, or roughly 60 times as much explosive. (This power makes sense given the M-80’s original purpose: simulating the sound of gunfire and artillery during military training missions.)

Read about how these changes came about at mental_floss. Link