Four hazards cause most construction deaths, every single year, and OSHA groups them as the Focus Four: falls, struck-by, caught-in or between, and electrocution. Control these four and you have handled the risks most likely to kill someone on your crew. Everything else in site safety sits underneath them. Here is each one and the rule that governs it.
Falls (the biggest killer by far)
Falls kill more construction workers than anything else. The core rule: fall protection is required at 6 feet or more above a lower level, on unprotected edges, and on scaffolds at 10 feet. Protection means guardrails, safety nets, or a personal fall-arrest harness. A few things trip people up:
- Holes and skylights need protection at any height, not just 6 feet.
- Residential is not exempt. The old carve-out for home building ended years ago. Roofs at 6 feet need real fall protection.
- Ladders: extend an extension ladder 3 feet above the landing, set it at a 4-to-1 angle, secure it, and keep three points of contact.
Not sure if a job needs protection? Run it through the Fall Protection Checker.
Struck-by
Moving vehicles, swinging loads, falling objects, and flying debris from tools. The protections: high-visibility clothing near equipment, a spotter for reversing machines, hard hats under any overhead work, toe boards and tethers so nothing drops, and never standing in the line of fire of a loaded machine.
Caught-in or between (trenches above all)
This is mostly trenching, and it is brutal because it is sudden. A cubic yard of soil weighs about as much as a small car, and a cave-in gives no warning. The rule: any trench 5 feet deep or more needs a protective system (sloping the walls back, shoring, or a trench box) unless it is solid rock or a competent person has cleared it. Never step into an unprotected trench, however quick the job. See Trenching and excavation safety.
Electrocution
Contact with power lines and faulty tools. The protections: keep clear of overhead power lines, use GFCI protection on all temporary site power, lock out and tag out before servicing anything energized, bin damaged cords, and call 811 to locate buried utilities before you dig.
The clearance is not one number, and getting the wrong one is how this hazard kills. For general equipment the minimum is 10 feet from a line rated 50 kV or below, plus 0.4 inch for every kV above 50 (1926.600(a)(6)). For a crane or derrick the trigger is 20 feet. Before the machine operates, the employer has to work out whether any part of it, the load line or the load could come within 20 feet of a line at its maximum working radius. If it could, one of three things is mandatory: the utility de-energizes and visibly grounds the line, or you hold a 20-foot clearance with the required encroachment precautions, or you work to the Table A distance for that line's voltage (1926.1408(a)(2)). The same 20-foot trigger applies while the crane is being assembled or dismantled (1926.1407(a)). A crew told "ten feet" around a crane has been given the wrong rule.
The one habit that ties it together
A competent person on site, checking conditions before each shift and after anything changes. Falls, trenches, and scaffolds all turn on someone qualified looking before work starts, not after something goes wrong.
Common questions
What are OSHA's Focus Four hazards?
The Focus Four are falls, struck-by, caught-in or between, and electrocution. OSHA groups them together because they cause most construction deaths every year. Control these four and you have handled the risks most likely to kill someone on your crew. They were formerly called the Fatal Four.
At what height does OSHA require fall protection?
Federal OSHA requires fall protection at 6 feet or more above a lower level in construction, and at 10 feet on scaffolds. Holes and skylights need protection at any height, not just 6 feet. Protection means guardrails, safety nets, or a personal fall-arrest harness. State-plan states can set stricter rules, so check Working in Your State.
Is residential construction exempt from fall protection?
No. The old exemption for home building ended years ago, so a roof at 6 feet needs real fall protection. Guardrails, nets, or a personal fall-arrest system are required unless the employer can show conventional protection is infeasible or a greater hazard, in which case a written fall-protection plan is required instead.
How far should equipment stay from overhead power lines?
It depends on the machine: 10 feet for general equipment, and 20 feet for a crane or derrick. Under 1926.600(a)(6) general equipment must stay at least 10 feet from a line rated 50 kV or below, plus 0.4 inch for every kV above 50. Under 1926.1408(a)(2) a crane operation triggers at 20 feet: if any part of the equipment, load line or load could get closer than that at maximum working radius, the employer must de-energize and ground the line, hold 20 feet with the required encroachment precautions, or work to Table A for that voltage. 1926.1407(a) applies the same 20-foot trigger to assembly and dismantling, and scaffolds have their own table at 1926.451(f)(6). Assume every overhead line is live, use a spotter when working near one, and never rely on the insulation of a line to protect you.
What is the difference between the Fatal Four and the Focus Four?
They are the same four hazards, just a renamed program. OSHA originally called falls, struck-by, caught-in or between, and electrocution the Fatal Four, then rebranded the training and outreach effort the Focus Four. The hazards and the rules behind them did not change.
The honest bit
- These are the federal OSHA floors. About 22 states run their own program and can require more. See Working in Your State.
- This is general guidance, not a substitute for proper training. The Focus Four are exactly where training and a competent person earn their keep.
Know someone who needs this?
Templates you might need
Sources
- OSHA Construction Focus Four Training · The four hazard categories that account for most construction fatalities
- 29 CFR 1926.1408 - Power line safety (up to 350 kV), equipment operations · The 20-foot trigger for a crane or derrick operating near a power line, and the three options once it is triggered: de-energize and ground, 20-foot clearance with encroachment precautions, or Table A clearance for the line's voltage
- 29 CFR 1926.600 - Equipment (general requirements) · The general equipment clearance at 1926.600(a)(6): 10 feet for lines rated 50 kV or below, plus 0.4 inch for each 1 kV over 50
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