The Fatal Four are the four leading causes of death in the construction industry: falls, struck-by incidents, electrocution, and caught-in/between hazards. Together, these four categories account for the majority of construction worker deaths every year. OSHA (the Occupational Safety and Health Administration) designates them as “Focus Four” hazards and requires them to be covered in all construction safety outreach training.
In 2024, construction and extraction workers experienced 1,032 fatalities in the United States. Understanding each of the Fatal Four helps workers recognize dangers on the job site before they turn deadly.
Falls: The Deadliest of the Four
Falls are the single largest killer in construction, and it’s not close. In 2023, 38.5% of all construction deaths were caused by falls, slips, and trips. The construction industry alone accounted for nearly half (47.8%) of every fatal fall across all U.S. workplaces that year. About 1 in 5 workplace deaths overall occurred in construction, and falls were the primary driver.
The numbers did improve slightly in 2024, with fatal falls among construction workers dropping 7.5% to 370 deaths, down from 400 the year before. But falls remain far ahead of the other three hazards in total body count. They happen from roofs, scaffolds, ladders, and elevated platforms. Workers who aren’t tied off, who use damaged fall protection, or who work on unstable surfaces face the highest risk. Guardrails, personal fall arrest systems, and safety nets are the primary defenses, but only when they’re actually in place and properly used.
Struck-By Incidents
A struck-by incident is exactly what it sounds like: a worker is hit by a moving object. In 2020, struck-by hazards caused 150 deaths and 14,000 nonfatal injuries in the construction sector. The objects doing the damage vary widely, but vehicles and heavy equipment are by far the most dangerous. In 2019, vehicles accounted for 47% of all struck-by construction fatalities, while falling objects caused another 27%.
Survey data from construction workers breaks it down further. The main causes of struck-by injuries include:
- Heavy equipment or vehicles: 36% of incidents
- Falling or flying objects from work at heights: 30%
- Falling or flying objects at the same level: 19%
Think of a crane swinging a load over a work area, a dump truck backing up, or tools dropping from scaffolding. Hard hats protect against some falling objects, but the real prevention starts with keeping workers out of the swing radius of equipment, securing tools and materials at height, and using spotters around moving vehicles.
Electrocution
Construction sites are full of electrical hazards that don’t exist in most other workplaces. The most common causes of electrical injuries on job sites are contact with overhead power lines, lack of ground-fault protection, missing or broken grounding paths, and improper use of extension cords and equipment.
Overhead power lines are particularly dangerous because they carry tens of thousands of volts and are typically uninsulated. A surprising range of everyday construction equipment can make contact: metal ladders, scaffolds, cranes, backhoes, raised dump truck beds, even aluminum paint rollers and long-handled concrete floats. OSHA’s general guidance is to stay at least 10 feet away from overhead lines and to assume any line is energized unless you’ve confirmed otherwise.
Ground faults are the other major electrical killer. Construction work is rough on equipment. Normal wear and tear breaks down insulation, exposes wires, and creates short circuits. Without ground-fault circuit interrupters (GFCIs) in place, that damaged equipment can send current through a worker’s body. Visually inspecting tools and cords before each use, pulling damaged equipment out of service, and using double-insulated tools are basic precautions that prevent these deaths.
Caught-In/Between Hazards
Caught-in or caught-between incidents happen when a worker’s body is squeezed, crushed, or pulled into machinery or collapsing materials. This category covers several distinct scenarios: getting a limb or clothing caught in rotating equipment like augers or gears, being crushed between two objects (such as a wall and a piece of heavy equipment), being buried in a trench collapse, or being compressed by shifting materials.
Trench cave-ins are among the most well-known examples. Unshored trenches can collapse without warning, burying workers under thousands of pounds of soil. Machinery entanglement is the other common scenario, where loose clothing, hair, or hands get pulled into unguarded moving parts. Proper shoring and sloping of trenches, machine guarding, and lockout/tagout procedures (shutting down and physically locking equipment before maintenance) are the primary defenses.
What Happens When Employers Ignore These Hazards
OSHA doesn’t just recommend addressing the Fatal Four. The agency enforces safety standards with significant financial penalties. A serious violation, meaning the employer knew or should have known about a hazard that could cause death or serious harm, carries a maximum fine of $16,550 per violation. Willful or repeated violations jump to $165,514 per violation. These amounts are adjusted annually for inflation.
Beyond fines, OSHA requires the Fatal Four to be a central part of construction safety training through its outreach program. Every worker who goes through OSHA 10-hour or 30-hour construction training receives instruction on all four hazard categories. The logic is straightforward: if these four hazards cause the most deaths, they deserve the most attention in training. For workers on job sites, knowing the Fatal Four isn’t just a training requirement. It’s a framework for scanning your environment and recognizing the specific dangers most likely to kill you.