Capping of reinforcing iron to prevent impalement is required by 1926.701(b) which states that all protruding reinforcing steel, onto and into which employees could fall, shall be guarded to eliminate the hazard of impalement.  There are specific rebar caps with steel reinforcement designed to provide impalement protection.

Federal OSHA has interpreted this standard to emphasize the effectiveness of the protection.

“When employees are working at any height above exposed rebar, fall protection/prevention is the first line of defense against impalement. Fall protection/prevention is also applicable when the rebar is below grade, e.g., footings or other excavations, where a fall into a trench would present an impalement hazard. When work is at grade, impalement exposure is dependent upon numerous situations and conditions; proximity of rebar to worker, height of rebar, e.g., working around rebar that is 3-6 feet high would not likely pose an impalement hazard. Rebar caps/covers are appropriate to prevent cuts, abrasions or other minor injuries when working at grade and there is no impalement hazard.

California regulations require that manufactured caps be at least 4 inches on a side or have a diameter of 4.5 inches if rounded. Any damaged cap of support system, including any that have arrested a fall, must be replaced immediately. Smaller “mushroom” caps do not provide impalement protection but may be used on horizontal rebar to prevent abrasions, cuts and minor injuries and to increase visibility.  Maintaining supplies of caps and/or supports throughout the site encourages their immediate use. Mushroom caps used on horizontal rebar should be of a different color from caps used to prevent impalement to facilitate usage control. Rebar may also be bent over so that it no longer presents an impalement hazard.

Regular use of rebar caps is enhanced by worker training and by maintaining supplies of capping systems or caps in all areas of the worksite where rebar is in place.