The Construction Focus Four: Falls, Struck-By, Caught-In/Between, Electrocution
Why these four
The Focus Four account for the majority of construction fatalities. They are not a single standard - they are an OSHA emphasis category - so exam questions test the specific rule behind each hazard.
Falls
The trigger height in construction is 6 feet (1926.501). Guardrail systems need a top rail at 42 inches ±3 inches and a midrail at about 21 inches; a toe board prevents falling objects. Covers over holes must support twice the intended load and be marked "HOLE" or "COVER." Workers must be trained as fall protection users (1926.503). Trap: 6 feet is construction, 4 feet is general industry, and scaffolds trigger at 10 feet. The 6-foot rule has almost no exceptions - a worker on a 7-foot wall needs protection.
Struck-by
Four categories: falling, flying, swinging, and rolling objects. Examples include dropped tools, nails from powder-actuated tools, crane-suspended loads, and vehicles backing up. Controls: toe boards and tool tethers, eye protection, exclusion zones under loads, spotters, and high-visibility apparel. Never stand or walk under a suspended load.
Caught-in/between
Crushing injuries between objects or into equipment. Excavations are the classic case: protective systems (sloping, shoring, shielding) are required at 5 feet unless the excavation is entirely in stable rock; a competent person inspects daily and after rain; spoil piles and equipment stay at least 2 feet from the edge; a ladder is needed when the trench is 4 feet deep, within 25 feet of lateral travel. Also covers machinery entanglement and unsecured loads.
Electrocution
Overhead lines, contact with energized equipment, faulty cords, and no lockout/tagout (1926.417). Use GFCIs or an assured equipment grounding conductor program, and keep equipment at least 10 feet from energized lines.
Rule of thumb
6 – 10 – 5: 6 feet for fall protection, 10 feet for scaffolds, 5 feet for trench protective systems.