The fatal four construction hazards and how to control each

We are not quoting fatality counts here, because they change every year and differ by source. For the latest, use OSHA and the Bureau of Labor Statistics directly.

1. Falls

Working at height, at an edge, on a roof, a ladder or a scaffold, or through an opening. The standards sit mainly in Subpart M for fall protection, Subpart L for scaffolds and Subpart X for ladders.

Strong controls: eliminate work at height by prefabricating on the ground, install guardrails and covers, then use personal fall arrest where those are not feasible. Plan rescue before anyone clips in. The fall protection guide goes through trigger heights by section, and the fall clearance calculator turns arrest distances into a worked number.

Exam trap: harnesses are not the first answer. They are the answer when higher controls are not feasible.

2. Struck-by

Being hit by a moving, falling, flying or swinging object: a tool dropped from above, a vehicle backing up, a swinging load, flying debris.

Strong controls: keep workers out of the line of fire with barricades and exclusion zones, use overhead protection, tether tools, plan traffic with spotters and keep loads under control. Hard hats are the last line.

Where to study: Subpart CC for cranes and derricks, plus the general rules on material handling and vehicles. The cranes guide covers the lifting rules by section.

3. Caught-in or between

Being crushed, pinned or trapped between objects, or inside something that collapses. Trench cave-ins, rotating machinery with missing guards and equipment backing into a worker at a wall are the classic cases.

Strong controls: protective systems for excavations, machine guarding, lockout and tagout, and keeping workers out of swing radii and pinch points. Do not enter a trench that has not been inspected by the competent person.

Where to study: Subpart P for excavations and the excavations guide. The trench sloping calculator helps you rehearse the engineering side.

4. Electrocution

Contact with energized lines, equipment or damaged cords. Overhead power lines near cranes, ladders and scaffolds are the repeat offenders, and so is portable equipment on wet ground.

Strong controls: de-energize and lock out, keep safe distances from lines, use ground-fault circuit interrupters on temporary power, inspect cords and use properly grounded tools.

Where to study: Subpart K and the electrical guide. Overhead line questions also appear in the crane rules.

How to use the four on the exam

Treat the Focus Four as a sorting tool. When a scenario describes an injury, ask which of the four it is, then ask which control level fits. That two-step habit gets you to the best answer faster than reading each option against the whole of 1926.

A quick practice routine: take any incident report from a site you know, label the hazard, then write the control at each level of the hierarchy. The hierarchy of controls examples show the method.

The remaining hazards still count

The Focus Four are about the most serious outcomes, not the entire blueprint. The CHST also covers health hazards such as silica, lead and noise, confined spaces, fire, material handling and more. Spread your study time by the weights, not by the headline hazards alone. The study guide does the split for you.

Try the check

Take the free 10-question check and see which hazard types you handle quickly and which slow you down. It needs no signup, and every answer comes with an explanation.

FAQ

Are the fatal four the same as the Focus Four?

Yes. Safety trainers use "fatal four" informally for what OSHA's outreach materials call the Focus Four.

Which of the four is most common?

Falls lead in OSHA and BLS data in recent years, but check current figures at the source before quoting them.

Do I need to memorize the percentages?

No. The CHST tests recognizing the hazard and choosing the strongest control, not recalling statistics.