The Fatal Four: construction's deadliest hazards and the controls that stop them

Year after year, four hazard categories account for well over half of construction fatalities. OSHA calls them the "Focus Four" — most of the industry calls them the Fatal Four. If you control these four, you eliminate the majority of ways people die on your sites.

1. Falls

Falls from elevation are the single largest killer, and the trigger height in construction is just six feet. The hierarchy is simple: eliminate the exposure (do the work on the ground), use passive protection (guardrails, covers), then personal fall arrest as the last line. The details are where crews die — unanchored harnesses, anchors that can't take 5,000 pounds, covers that aren't secured or marked, and no rescue plan for a worker hanging in a harness. Suspension trauma can kill in minutes; if your fall protection plan ends at "call 911," it isn't a plan.

2. Struck-by

Vehicles, swinging loads, and flying objects. The controls: high-visibility clothing and internal traffic control plans wherever equipment operates, never positioning workers under suspended loads, taglines on loads, and inspecting rigging before every lift. Tool tethering and toe boards matter more as work goes vertical.

3. Caught-in / caught-between

Trench collapses dominate this category. A cubic yard of soil weighs about as much as a pickup truck; an unprotected five-foot trench is a burial waiting to happen. Protective systems — sloping, shoring, or shielding — are required at five feet, and a competent person must inspect excavations daily and after every rain. The same category covers equipment rollovers and workers caught in unguarded machinery: keep guards on, use lockout/tagout, and never position yourself between moving equipment and a fixed object.

4. Electrocution

Overhead lines, damaged cords, and missing ground-fault protection. Keep equipment at least 10 feet from lines up to 50kV (more above that), treat every line as energized until the utility confirms otherwise, use GFCIs on all temporary power, and pull damaged cords from service immediately. Lockout/tagout applies to electrical work the same as mechanical.

Train on it, then talk about it

A course builds the base, but the Fatal Four are won or lost in daily planning: pre-task talks that name the day's specific exposures, supervisors empowered to stop work, and near-miss reporting that actually gets read. Awareness training plus daily reinforcement is the combination that moves the numbers.