1. Falls from Height
The Leading Cause of Death in Construction
Falls consistently top the list for fatal injuries in construction. This hazard exists wherever work is done above ground level—from rooftops and scaffolds to ladders and unprotected edges.
Common Scenarios:
Working on roofs without proper fall protection (guardrails, personal fall arrest systems).
Using ladders that are damaged, unstable, or improperly angled.
Working on scaffolding without guardrails or secure planking.
Walking or working on surfaces with unprotected holes or floor openings.
Key Mitigation Strategies (The "Hierarchy of Controls"):
Elimination/Substitution: Can the task be done from the ground? Prefabricate sections at ground level.
Engineering Controls: Install permanent guardrails, protective covers over floor holes, and properly constructed scaffolds.
Administrative Controls: Implement strict procedures for working at height, including permits and planning.
Personal Protective Equipment (PPE): When other controls aren't enough, ensure use of properly fitted fall arrest harnesses, lanyards, and secure anchor points.
Pro Tip: The 6-foot rule (OSHA's requirement for fall protection at 6 feet and above in the U.S.) is a bare minimum. A culture of "100% tie-off" whenever off the ground is far safer.
2. Struck-By Hazards
When Moving Objects and Workers Collide
A "struck-by" injury occurs when a worker is hit by a moving object, vehicle, or piece of equipment. The force of construction machinery makes these incidents particularly severe.
Four Main Sub-Categories:
Struck-by-Flying Object: Nail gun recoil, broken tool parts, or debris from grinding.
Struck-by-Falling Object: Tools, materials, or debris dropped from a higher level.
Struck-by-Swinging Object: The arc of a crane's load or the backhoe bucket.
Struck-by-Rolling Object: Being run over by a moving vehicle (truck, grader, roller) or caught between equipment and a fixed object.
Key Mitigation Strategies:
Separation of People and Traffic: Establish clear pedestrian routes separate from site vehicle zones. Use spotters for backing vehicles.
Secure Materials and Tools: Use toe boards, tool lanyards, and debris nets to prevent objects from falling.
Visibility: Ensure high-visibility (hi-vis) PPE is worn by all personnel. Equip vehicles with alarms and working lights.
Exclusion Zones: Establish and enforce clear "no-go" zones around the swing radius of cranes and heavy equipment.
3. Electrocution
The Invisible and Instant Killer
Construction sites are full of temporary power, exposed wiring, and work near overhead or underground utilities. Electricity always seeks the path of least resistance to ground—and that path can be through a human body.
Common Sources:
Contact with overhead power lines (a major risk for crane and scaffold work).
Damaged or frayed extension cords, tools, and temporary lighting.
Working in wet conditions with portable electric tools.
Contact with buried or hidden electrical lines during excavation.
Key Mitigation Strategies:
Look Up and Look Out: Always assume overhead lines are energized. Maintain safe minimum approach distances (e.g., 10 feet for lines up to 50kV).
Call Before You Dig: Contact utility locating services (like 811 in the U.S.) to mark underground lines before any excavation.
Inspect and Protect: Use GFCI (Ground-Fault Circuit Interrupter) protection for all temporary power outlets. Daily inspect cords and tools for damage.
De-energize and Lock Out: The safest practice is to de-energize and lockout/tagout circuits before working on them.
4. Caught-In/Between Hazards
When a Worker is Crushed or Trapped
This gruesome hazard occurs when a worker is caught, crushed, squeezed, or pinched between two or more objects.
Common Scenarios:
Trench and Excavation Collapses: The leading cause. Unprotected trenches can bury workers in seconds under thousands of pounds of soil.
Equipment Hazards: Getting caught in the moving parts of machinery (conveyors, saws) or between a piece of equipment and a fixed structure.
Collapsing Materials: Being pinned under collapsing materials like brick stacks or unsecured structural components.
Key Mitigation Strategies (Especially for Trenches):
Slope, Shore, or Shield: This is the cardinal rule for trench safety. Trenches 5 feet deep or more must have a protective system.
Slope the trench walls back at a safe angle.
Shore the walls with supports like hydraulic jacks.
Shield the workers with a trench box.
Machine Guarding: Ensure all moving parts on equipment have proper guards in place.
Safe Work Practices: Never enter an unprotected trench. Keep heavy equipment and spoil piles away from the trench edge.
5. Airborne and Material Hazards
The Silent, Long-Term Threats
Not all construction hazards cause immediate injury. Many involve exposure to harmful substances that lead to chronic, debilitating illnesses years later.
Common Exposures:
Silica Dust: Generated when cutting, grinding, or drilling concrete, brick, or stone. Inhalation can cause silicosis, an incurable lung disease.
Asbestos: Still found in older buildings during renovation/demolition. Causes lung cancer and mesothelioma.
Loud Noise: Prolonged exposure to equipment noise leads to permanent hearing loss.
Chemical Hazards: Solvents, adhesives, lead, and other toxic materials present in paints, coatings, and treatments.
Key Mitigation Strategies:
Wet Methods: Use water to suppress dust at the source when cutting masonry.
Ventilation and Containment: Use local exhaust ventilation (LEV) and enclosures for dust-generating tasks.
Respiratory Protection: Where engineering controls aren't enough, select the right respirator (e.g., N95 for dust, supplied air for asbestos) and ensure proper fit-testing.
Hearing Conservation: Implement a program that includes monitoring noise levels, providing hearing protection (earplugs, muffs), and offering audiometric testing.
Building a Proactive Safety Culture
Knowing these five hazards is crucial, but knowledge alone doesn't create safety. The most effective sites build a proactive safety culture where:
Pre-Task Planning is routine for every activity, especially non-routine jobs.
Hazard Reporting is encouraged, not punished.
Continuous Training goes beyond paperwork to ensure real comprehension.
Everyone Feels Empowered to stop work if a hazard is not controlled.
Safety on a construction site isn't just a list of rules; it's a mindset of constant awareness and mutual responsibility. By systematically identifying these common hazards and implementing robust controls, we can ensure every worker returns home safely at the end of the day.
Construction Hoist Overload Indicator and Sensor