Simply stated, unguarded protruding steel reinforcing bars are a serious construction site hazard. Even if you just stumble onto an unguarded rebar you can impale yourself, resulting in serious internal injuries or death. Minimize this danger by guarding all protruding ends of steel rebar with rebar caps or wooden troughs, or bend rebar so exposed ends are no longer upright.
It may take a little more time to cap each bar, but isn’t that time well spent compared to the time spent recovering from an impalement injury? Furthermore, OSHA Standards requires that rebar "be guarded to eliminate the hazard of impalement."
Despite OSHA’s requirement, it’s important to be aware that not all guards provide that level of protection. In fact, in some circumstances, the force of a fall can cause rebar to push clear through a plastic cap and still cause impalement. Fall protection/prevention equipment is the first line of defense when employees are working at any height above exposed rebar, but you must still have the rebar guarded to minimize the risk of injury.
Exposed, unguarded rebar is a serious job site hazard and can cause significant bodily harm. Take the time to minimize the opportunity for an injury to occur and cap ‘em!