Every OSHA 10 and OSHA 30 class in construction spends most of its required hours on the same four hazards. That’s not laziness — it’s statistics. The Focus Four account for the majority of construction fatalities year after year.
The numbers behind the training
| Hazard | Share of construction deaths | Classic scenario |
|---|---|---|
| Falls | ~35–40% | Unprotected roof edge, misused ladder |
| Struck-by | ~10–15% | Reversing vehicle, dropped load |
| Electrocution | ~8% | Overhead line contact, damaged cord |
| Caught-in/between | ~5–7% | Trench cave-in, rotating equipment |
Remember: the percentages shift a little each year, but the ranking barely moves. Learn these four cold and you understand most of what kills construction workers.
1. Falls — the number one killer
Construction’s fall-protection threshold is 6 feet (general industry is 4). The big three fall sources are roofs, ladders, and scaffolds. What the exam wants you to know:
- Guardrails, safety nets, or personal fall arrest — one of them must be in place at 6 feet.
- A personal fall arrest system needs an anchor rated for 5,000 lbs per worker.
- Ladders: 4:1 angle, 3 feet above the landing, never on the top rung.
Our Falls practice quiz includes photo questions where you spot the missing guardrail or the bad ladder setup — the same way you’d catch it on site.
2. Electrocution — the invisible one
You can’t see voltage. The exam focuses on the safe-distance and equipment rules:
- 10 feet minimum from overhead power lines up to 50kV.
- GFCIs or an assured equipment grounding program on all receptacle outlets that aren’t part of the permanent wiring.
- Damaged cords and missing ground prongs come out of service — no tape jobs.
Test yourself with the Electrocution quiz.
3. Struck-by — vehicles, loads, and flying objects
Struck-by deaths cluster around vehicles and equipment. Key points:
- Never position yourself between moving and fixed objects.
- High-visibility clothing near traffic and equipment.
- Stay clear of suspended loads and rigging — and never under them.
Try the Struck-by quiz — several questions use real crane and forklift photos.
4. Caught-in/between — trenches above all
The signature caught-in hazard is the trench cave-in. A cubic yard of soil weighs as much as a small car, and an unprotected trench can collapse in seconds:
- Protection (sloping, shoring, or a trench box) required at 5 feet.
- A competent person must inspect excavations daily and after every rainstorm.
- Spoil piles stay at least 2 feet back from the edge.
The Caught-in/Between quiz covers trenches, unguarded machinery, and pinch points.
Learn them in both languages
Every Focus Four lesson and question in the SafePath OSHA 10 app is available in English and Spanish — because a hazard warning only works if the whole crew understands it. Estudia los Cuatro Peligros en español.
Frequently Asked Questions
What are the Focus Four hazards?
Falls, electrocution, struck-by, and caught-in/between. OSHA calls them the Focus Four because together they cause the majority of construction worker deaths.
What is the deadliest hazard in construction?
Falls. They account for more than one in three construction fatalities, most often from roofs, ladders, and scaffolds. That's why fall protection is required at 6 feet in construction.
What's the difference between struck-by and caught-in/between?
If the impact alone injures you — a falling tool, a reversing truck — it's struck-by. If you're crushed, squeezed, or pinned between objects — a trench cave-in, equipment against a wall — it's caught-in/between.
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Free practice questions from every topic — in English and Spanish.