Struck-By Hazard Prevention: The Second Fatal Four Hazard

The Four Struck-By Categories

• Flying: particles and fragments from grinding, cutting, and nailing, controlled by guards and eye protection.
• Falling: tools and materials from above, controlled by toe boards, screens, and hard hats.
• Swinging: crane and equipment loads, controlled by exclusion zones and tag lines.
• Rolling: vehicles and mobile equipment, controlled by spotters, backup alarms, and high-visibility apparel.

Exclusion Zones and Spotters

Most serious struck-by events involve vehicles and swinging loads. Keeping workers out of the swing radius and the path of equipment, with spotters and barricades, is the highest-return control.

Part of the Fatal Four

Struck-by sits with falls and caught-between as construction fatal-four hazards, central to construction safety training and crane and rigging work.

Vehicle and Equipment Traffic Control

Traffic control plans separate pedestrians from vehicles and equipment. High-visibility clothing, signs, barriers and trained spotters reduce struck-by incidents on job sites and in yards.

Review the plan at the start of each shift when conditions change.

Falling and Flying Objects

Overhead work can drop tools and materials. Toe boards, debris nets, tool lanyards and hard hats reduce risk. Keep workers out of the drop zone below overhead work.

Inspect rigging and secure loads before lifting.

Reporting and Learning From Near Misses

Near misses show where the next injury may occur. A simple, blame-free reporting method encourages workers to speak up. Use the reports to adjust plans and training.

Supervisors should walk the site regularly and correct hazards quickly.

Hard Hats and High Visibility

Protective equipment reduces injury and improves visibility. Choose the right type and maintain it.

Wear it correctly.

Securing Tools and Materials

Tethering tools and securing loads prevent objects from falling. Use toe boards and nets where needed.

Planning reduces risk.

Pre Task Planning

Discuss hazards, traffic patterns and roles before work begins. Update plans when conditions change.

Everyone should know the plan.

What Struck By Means

A struck by incident occurs when a person is injured by a moving object, whether it is falling, flying, swinging or rolling. It is one of the leading causes of fatal injury in construction and heavy industry.

The category is broad because the energy source varies: a dropped tool, a vehicle in reverse, a suspended load, a pressurized component or a piece of material released under tension.

Recognizing the category helps because the controls are similar even when the situations look unrelated.

Falling and Dropped Objects

Anything at height is a potential falling object, and the energy at impact is significant even for small items dropped from a few floors.

Controls include toe boards, debris netting, tool tethering, barricading the area below and prohibiting work directly beneath overhead operations.

Hard hats reduce severity but do not prevent these incidents, and treating them as the control rather than the last layer is a recognized failure pattern.

Vehicles and Mobile Equipment

Workers on foot struck by vehicles and equipment account for a large share of fatalities, particularly in yards, roadway work zones and congested sites.

Separation of pedestrians from equipment through planned routes and barriers is far more effective than relying on visibility and attention.

Blind spots on heavy equipment are substantial. Spotters, cameras, proximity systems and eye contact protocols exist because the operator genuinely cannot see.

Suspended and Swinging Loads

Loads under a crane or hoist can swing, rotate or shift, and the area they could reach is larger than people assume.

Tag lines, exclusion zones and prohibiting anyone from passing under a suspended load are the basic controls, and the last is violated routinely.

Rigging failures produce sudden, uncontrolled movement, which is why inspection of slings and hardware before each lift is required rather than periodic.

Released Energy and Flying Objects

Cutting, grinding, nailing and compressed air operations produce flying fragments, and eye and face protection must match the specific hazard.

Stored energy in springs, pressurized systems, tensioned materials and loaded structures releases suddenly when disturbed, and this is where planning matters more than equipment.

Materials stacked, banded or shored improperly release without warning, and unstacking is one of the more common struck by situations.

Planning and Training

Most struck by incidents were foreseeable. Planning the work to eliminate the exposure, rather than protecting people within it, is what prevents them.

Job briefings, exclusion zones and coordination between trades working at different levels are the practical mechanisms.

Simulation and hazard recognition training help workers see the exposures that experience otherwise teaches slowly, and employer procedures and applicable regulations govern.

Common Mistakes and How to Avoid Them

Recurring errors include working beneath overhead operations, passing under suspended loads, approaching equipment without operator acknowledgment, failing to tether tools at height and disturbing stored energy without releasing it first.

Supervisors can help by making it acceptable to pause and ask. A culture where questions are treated as competence rather than weakness produces fewer errors in struck by hazards.

How Employers Evaluate Readiness

Employers assess this through incident and near miss records, observation during site audits, whether exclusion zones are respected and the quality of pre task planning.

Keeping Skills Current

Sites, equipment and work sequences change daily. Reassessing overhead and equipment exposures at the start of each task prevents relying on conditions that were true yesterday.

Planning and Preparation

Preparation includes identifying what could move or fall, establishing exclusion zones, coordinating with other trades working above or nearby, inspecting rigging and confirming how pedestrians and equipment will be separated.

Documentation That Holds Up

Reporting near misses, dropped objects and equipment conflicts is what allows a site to correct a layout or sequence problem before it produces an injury.

Frequently Asked Questions