Jackhammers often create clouds of dust, and sometimes that dust can be dangerous. For example, breaking up concrete pavement can release crystalline silica, which is known to cause lung cancer. To keep dust levels down, workers can attach a hose that sprays a mist of several ounces of water per minute, wetting the work area for a safer breathing environment.
Shrapnel is not unusual, so it's a really good idea to wear long, tough pants and long-sleeved shirts. Steel-toed boots are also recommended. And because jackhammers are heavy, some have optional lift-assist technology that pushes the tool upwards out of the ground, making it much easier to move around in the work area.
Although jackhammers make quick work of many substrates, they aren't the right tool for every demolition job. On some sites, buried gas or electrical lines might lurk beneath the surface, just waiting for a jackhammer's hefty bite to suddenly make the local emergency room a lot more exciting.
It's easy to point out the dangers of jackhammers. They are powerful machines with potential for serious destruction. But, of course, destruction is the whole point. Without their fantastic pounding power, we'd be stuck with horribly inefficient pickaxes and shovels and sledgehammers. And no matter how strong you might be, you definitely do not want to break up an old highway by hand.