Fatal Four: Top Construction Safety Hazards and Prevention Strategies

Key Takeaways

• The Fatal Four—falls, struck-by objects, electrocutions, and caught-in/between incidents—are the leading causes of fatalities in the construction industry.
• Awareness and prevention of these hazards are essential for reducing workplace deaths.
• Falls are the most common cause of construction accidents, often resulting from inadequate fall protection, improper ladder use, and unsecured scaffolds.
• Struck by objects injuries can occur from falling, swinging, or rolling objects, and are often the result of inadequate securing of materials, poor site organization, and unsafe operation of vehicles and equipment.
• Electrocution hazards are primarily caused by contact with live electrical circuits, overhead power lines, and improperly grounded equipment.
• Caught-in/between incidents involve workers being trapped or crushed by machinery, collapsing structures, or heavy materials.

 

What is the OSHA Fatal Four?

Among the various hazards present in the workplace, OSHA has identified four primary causes of fatalities in the construction industry, commonly referred to as the "Fatal Four." These Fatal Four hazards account for a significant portion of all construction-related deaths each year and include falls, struck-by objects, electrocutions, and caught-in/between incidents.

While the Fatal Four represent the most significant causes of fatal incidents in construction sites, other common workplace hazards also pose serious risks in various industries. These include:

• Hazardous Substances: Exposure to toxic chemicals, dust, fumes, and other hazardous substances can lead to serious health issues, including respiratory problems, skin irritation, and long-term illnesses like cancer.
• Musculoskeletal Disorders (MSDs): Repetitive motions, heavy lifting, and awkward postures can cause musculoskeletal disorders, such as back injuries, carpal tunnel syndrome, and tendonitis
• Noise Hazards: Prolonged exposure to high levels of noise can result in hearing loss and other health issues.
• Confined Spaces: Working in confined spaces, such as tanks, silos, and tunnels, poses unique hazards, including oxygen deficiency, toxic atmospheres, and the risk of entrapment.
• Heat Stress: Workers exposed to high temperatures, particularly in outdoor environments or hot industrial settings, are at risk of heat stress, which can lead to heat exhaustion, heat stroke, and other heat-related illnesses.
• Machine-Related Hazards: Beyond caught-in/between incidents, other machine-related hazards include amputation risks, entanglement in moving parts, and equipment malfunctions.

Purpose of the OSHA Fatal Four

The concept of the OSHA Fatal Four serves a critical purpose in workplace safety by aiming to raise awareness among employers, workers, and safety professionals. The classification of the Fatal Four is not merely an identification of risks but a strategic approach to focus on prevention and education.

The primary objectives of the OSHA Fatal Four include:

• Awareness: Bringing attention to the leading causes of fatalities in the construction industry. By understanding the Fatal Four, stakeholders can prioritize safety measures and allocate resources effectively to address these critical areas.
• Education and Training: Providing targeted training and educational resources to workers and employers. OSHA's emphasis on the Fatal Four helps in developing specific training programs that address the unique challenges associated with each hazard.
• Safety Strategies: Encouraging the implementation of comprehensive safety strategies to prevent fatal incidents. This includes developing and enforcing safety protocols, using appropriate personal protective equipment (PPE), regular safety audits, and fostering a culture of safety on construction sites.
• Regulatory Compliance: Ensuring adherence to OSHA standards and regulations designed to protect workers from these hazards. Compliance with OSHA's guidelines helps minimize risks and reduce the likelihood of fatal accidents.

Fatal Four Hazards: Identification and Prevention

Below are the OSHA Fatal Four hazards that represent the most significant dangers and are responsible for the majority of fatalities in the construction industry.

Falls

Falls are the leading cause of fatalities in the construction industry. According to the Bureau of Labor Statistics report, 1 in 5 workplace deaths occurred in construction sites and 38.4% of which were a result of falls, slips, and trips from height. The risk of falls is particularly high in construction due to the nature of the work, which often involves working at heights, on scaffolds, ladders, roofs, and other elevated surfaces. Falls occur when a worker loses balance and drops from an elevated surface or even at the same level, resulting in injury or death.

Common Occurrences and Risks

• Scaffolding Accidents: Scaffolding is commonly used in construction to provide workers with access to elevated areas. However, if scaffolds are not properly erected, maintained, or used, they can lead to serious falls. Risks include inadequate guardrails, unstable surfaces, and lack of proper access.
• Ladder Falls: Ladders are another common source of falls. Misuse of ladders, such as overreaching, using the wrong type of ladder, or placing ladders on uneven surfaces, can easily result in falls. Workers may also fall if they carry heavy loads while climbing, causing them to lose balance.
• Roof Falls: Working on roofs presents a high risk of falls, especially if the roof is steep, slippery, or lacks proper edge protection. Falls from roofs are often fatal due to the height and impact of the fall.
• Falls Through Openings: Openings in floors, roofs, or walls, such as skylights or unguarded edges, pose a significant risk of falls. Workers may inadvertently step into or through these openings if they are not properly guarded or marked.
• Slips, Trips, and Falls at Ground Level: While falls from heights are the most dangerous, slips, trips, and falls at ground level can also result in serious injuries. Common causes include wet or uneven surfaces, cluttered walkways, and poor lighting.

Safety and Prevention Strategies

OSHA has established specific regulations for fall protection, particularly in the construction industry, to minimize the risk of falls. Key requirements include:

Fall Protection Systems
The use of fall protection systems is essential for preventing falls from heights. These systems include guardrails, safety nets, and personal fall arrest systems (PFAS). Guardrails should be installed around open edges, while safety nets can catch workers if they fall. PFAS, such as harnesses and lanyards, should be properly fitted and anchored to secure points.

Proper Ladder Use
To prevent ladder falls, workers should use ladders that are appropriate for the task and follow safe practices, such as maintaining three points of contact, not overreaching, and ensuring the ladder is on a stable surface. Ladders should be regularly inspected for defects and properly maintained.

Scaffold Safety
Scaffolds must be erected and dismantled by trained and competent personnel. They should be inspected regularly to ensure stability, and guardrails should be installed to prevent falls. Workers should also be trained on safe scaffold use and access.

Struck By Objects

Struck-by incidents involve any incident where a worker is hit by an object, equipment, or vehicle. This can include being struck by tools or materials that fall from heights, being hit by moving vehicles or machinery, or being impacted by objects that are thrown, projected, or swinging.

The construction environment is particularly prone to struck-by hazards due to the constant movement of materials, equipment, and vehicles. These incidents are often the result of inadequate safety measures, poor communication, or lack of awareness.

Common Occurrences and Risks

• Falling Objects: One of the most common struck-by hazards involves objects falling from heights. This can occur when tools, materials, or debris are not properly secured and fall from scaffolds, ladders, or other elevated surfaces. Workers below are at risk of being struck, especially if they are not wearing hard hats or if the area is not properly barricaded.
• Moving Equipment and Vehicles: Construction sites often have heavy machinery and vehicles moving around, such as excavators, forklifts, and trucks. Workers are at risk of being struck by these machines, particularly if they are in the blind spots of operators or if the equipment is not properly maintained.
• Swinging or Projected Objects: Objects that swing, like hoisted loads, or that are projected, such as tools thrown by machinery or debris ejected by power tools, can cause serious injuries. Workers in the path of these objects are at significant risk, especially if they are not aware of the danger or if the area is not properly cordoned off.
• Unsecured Materials: Materials that are not properly secured can shift, roll, or slide, causing them to strike workers. This is common with pipes, lumber, and other large materials that may be stacked or stored improperly.

Safety and Prevention Strategies

Preventing struck-by incidents requires a holistic approach that includes the use of protective equipment, proper worksite organization, and training. OSHA provides guidelines for reducing struck-by hazards:

Proper Securing of Tools and Materials
Tools and materials should always be secured when working at heights. This can include using tool lanyards, securing loads with netting or straps, and ensuring that materials are stacked in a stable manner. Workers should also be trained to avoid working directly below areas where materials are being hoisted or stored.

Safe Operation of Machinery and Vehicles
Operators of heavy machinery and vehicles should be trained and certified to operate the equipment safely. This includes understanding the machine's blind spots, using spotters when backing up, and following proper signaling and communication protocols. Regular maintenance of equipment is also essential to prevent mechanical failures that could lead to struck-by incidents.

Site Organization and Communication
Proper organization of the worksite can help reduce the risk of struck-by incidents. This includes clearly marking hazardous areas, using barriers and warning signs, and ensuring that walkways are free from obstructions. Good communication among workers and between operators and ground personnel is crucial for coordinating movements and preventing accidents.

Electrocution

Electrocution occurs when a person is exposed to a lethal amount of electrical energy, resulting in death. It is a result of direct contact with live electrical circuits, equipment, or power lines. The human body, being a good conductor of electricity, allows electrical currents to pass through, which can cause severe injury or death depending on the voltage and duration of exposure.

Electrical hazards are most common in environments where electrical systems are being installed, repaired, or maintained, but they can occur in any situation where live electrical components are present. Workers who are not properly trained or who do not follow safety protocols are at increased risk of electrocution.

Common Occurrences and Risks

• Contact with Overhead Power Lines: One of the most common causes of electrocution in construction is accidental contact with overhead power lines. This can happen when workers are using ladders, cranes, or other equipment near power lines, or when materials are being hoisted. The high voltage in power lines can cause instant electrocution if contact is made.
• Improper Use of Electrical Tools and Equipment: Using electrical tools and equipment that are not properly maintained or grounded can lead to electrocution. For example, damaged insulation, exposed wiring, or faulty connections can create a direct path for electrical current to pass through the body. This is particularly hazardous when working in wet or damp conditions, which can increase the conductivity of electrical currents.
• Contact with Live Electrical Circuits: Workers performing electrical installations, repairs, or maintenance may inadvertently come into contact with live circuits if proper lockout/tagout procedures are not followed. This can happen during tasks such as wiring, circuit testing, or equipment installation, where electrical systems are not properly de-energized.
• Inadequate Grounding: Electrical systems that are not properly grounded pose a significant electrocution risk. Grounding provides a safe path for electrical currents to dissipate into the earth, but if grounding is insufficient or faulty, electrical currents may travel through other paths, including through workers who come into contact with the system.

Safety and Prevention Strategies

Preventing electrocutions requires a combination of safe work practices, proper equipment maintenance, and comprehensive training. OSHA provides a comprehensive guideline on how to protect workers from the risks associated with electrical hazards:

Use of Ground-Fault Circuit Interrupters (GFCIs)
GFCIs are devices that protect workers from electrical shock by quickly shutting off power if an imbalance in the electrical current is detected. They are particularly important in environments where electricity is used near water, such as construction sites where power tools are used in wet conditions. Installing and using GFCIs on all temporary power sources can significantly reduce the risk of electrocution.

Proper Lockout/Tagout Procedures
Lockout/tagout procedures are critical for ensuring that electrical systems are de-energized before maintenance or repair work begins. These procedures involve isolating the electrical energy source and placing lockout devices and tags on the system to prevent it from being re-energized until the work is complete. Workers should be thoroughly trained in these procedures and should always follow them when working with electrical systems.

Maintaining and Inspecting Electrical Equipment
Regular maintenance and inspection of electrical tools and equipment are essential for preventing electrocutions. This includes checking for damaged insulation, poorly maintained extension cords, exposed wires, and other signs of wear and tear that could lead to potential electrical hazards. Faulty equipment should be repaired or replaced immediately, and tools should always be used in accordance with manufacturer guidelines.

Avoiding Contact with Power Lines
Workers should always assume that overhead power lines are energized and maintain a safe distance from them. OSHA recommends maintaining a minimum clearance of 10 feet from power lines, with greater distances required for higher voltages. When working near power lines, non-conductive tools and equipment should be used, and power lines should be de-energized if possible.

Caught-In/Between

Caught-in/between incidents occur when a worker is caught, crushed, or compressed between two or more objects. This type of hazard is particularly prevalent in construction, where workers are often in close proximity to heavy machinery, equipment, and structures.

Caught-in/between incidents occur in a variety of situations, such as being caught in machinery, crushed by collapsing structures, or trapped between vehicles and walls. The force involved in caught-in/between incidents can cause severe injuries, including fractures, amputations, and internal injuries, and they are often fatal due to the crushing nature of the incidents.

Common Occurrences and Risks

• Machinery and Equipment: Workers are at risk of being caught in machinery or equipment if proper guards are not in place. For example, moving parts on machines, such as gears, belts, and pulleys, can catch workers' clothing or limbs, pulling them into the machinery. Similarly, workers may be crushed if machinery unexpectedly starts up while they are performing maintenance or repairs.
• Excavation and Trenching: Excavation and trenching work pose significant caught-in/between risks, particularly if trenches are not properly shored or if the ground is unstable. Trench collapses can bury workers in soil or debris, trapping them and leading to suffocation or crushing injuries. Even small collapses can be deadly, as the weight of the soil can make escape impossible.
• Collapsing Structures: Workers can be caught or crushed by collapsing structures, such as walls, scaffolds, or buildings under construction or demolition. These incidents can occur due to structural instability, improper construction practices, or external forces like strong winds or seismic activity.
• Vehicles and Heavy Equipment: Construction sites often have vehicles and heavy equipment moving around, posing a risk of workers being caught between the vehicle and another object, such as a wall or another piece of equipment. This is particularly dangerous when vehicles are backing up or maneuvering in tight spaces, where visibility may be limited.

Safety and Prevention Strategies

Preventing caught-in/between incidents requires strict adherence to safety protocols, proper equipment maintenance, and comprehensive training. OSHA provides guidelines for reducing the risks associated with caught-in/between hazards:

Machine Guarding
All machinery with moving parts should be equipped with appropriate guards to prevent workers from coming into contact with hazardous areas. Machine guards should be securely attached and inspected regularly to ensure they are in good condition. Workers should never remove or bypass guards while machinery is in operation, and they should be trained to recognize the importance of machine guarding.

Excavation and Trenching Safety
OSHA has specific regulations for excavation and trenching work, including requirements for protective systems such as shoring, shielding, and sloping to prevent collapses. Trenches should be inspected by a competent person before work begins and throughout the day to ensure that conditions remain safe. Workers should also be trained on the hazards of excavation work and the proper use of protective systems.

Structural Safety
Ensuring the structural integrity of buildings, scaffolds, and other structures is essential for preventing collapses. This includes following proper construction practices, regularly inspecting structures for signs of instability, and avoiding overloading or compromising the structure. Workers should also be trained to recognize the signs of potential collapse and know how to respond in the event of an emergency.

Safe Use of Vehicles and Equipment
Operators of vehicles and heavy equipment should be trained and certified to operate the equipment safely. This includes understanding the vehicle's blind spots, using spotters when backing up, and following proper signaling and communication protocols. Workers should be aware of the hazards associated with moving equipment and stay clear of operating areas unless necessary.

 

Implementing Safety Measures

To effectively address the hazards that contribute to the Fatal Four—falls, struck-by objects, electrocutions, and caught-in/between incidents—OSHA has established a comprehensive set of standards and regulations. These regulations are designed to protect workers by setting minimum safety requirements and guidelines for employers to follow:

• 29 CFR 1926.501 – Duty to Have Fall Protection: This regulation mandates that employers must provide fall protection for workers at heights of six feet or more in construction. The standard outlines various types of fall protection systems, including guardrails, safety nets, and personal fall arrest equipment.
• 29 CFR 1926.502 – Fall Protection Systems Criteria and Practices: This standard provides detailed requirements for the design, installation, and use of fall protection systems. It covers everything from the strength and durability of guardrails and safety nets to the proper use of harnesses and lanyards in a PFAS.
• 29 CFR 1910 Subpart D – Walking-Working Surfaces: While primarily focused on general industry, this regulation also applies to construction environments where workers use walking-working surfaces. It includes requirements for slip resistance, guardrails, and fall protection systems to prevent falls from elevated surfaces.
• 29 CFR 1926.600 – Equipment: This regulation covers the operation of vehicles and heavy equipment on a construction site. It requires that all equipment must be properly maintained, operated by trained personnel, and equipped with the necessary safety features.
• 29 CFR 1926.601 – Motor Vehicles: This standard specifically addresses the use of motor vehicles on construction sites. It requires that vehicles be equipped with audible backup alarms, mirrors, and other safety devices to prevent struck-by incidents.
• 29 CFR 1926.651 – Specific Excavation Requirements: While primarily focused on excavation, this regulation also addresses the risks of struck-by hazards during trenching and excavation work. It includes requirements for securing materials, using protective systems to prevent collapses, and ensuring that workers are not in the path of moving equipment or materials.
• 29 CFR 1926 Subpart K – Electrical: This section of OSHA’s construction standards focuses on electrical safety, covering everything from the installation of electrical systems to the use of temporary power.
• 29 CFR 1910.147 – The Control of Hazardous Energy (Lockout/Tagout): While primarily a general industry standard, the lockout/tagout regulation is crucial for preventing electrocutions during maintenance and repair work. It requires that all energy sources be isolated and locked out before work begins, ensuring that machinery and electrical systems cannot be accidentally energized.
• 29 CFR 1926.416 – Electrical Safety-Related Work Practices: This regulation requires that workers avoid contact with live electrical circuits by either de-energizing and grounding the circuits or using insulated tools and PPE.
• 29 CFR 1926.702 – Requirements for Equipment and Tools: This standard addresses the safe operation of machinery and equipment, including the requirement for machine guards to protect workers from moving parts.
• 29 CFR 1926.652 – Requirements for Protective Systems: This regulation is specific to excavation and trenching work, where the risk of being caught in or buried by collapsing soil is significant.
• 29 CFR 1910.212 – General Requirements for All Machines: While this standard is part of the general industry regulations, it also applies to construction settings where machinery is used. It requires that all machines be equipped with appropriate guards to protect workers from hazards like rotating parts, flying chips, and sparks, which can lead to caught-in/between injuries.

To enhance workplace safety and prevent accidents related to OSHA's Fatal Four, the following measures and approaches should be implemented:

Training and Education - Providing comprehensive safety training and education to all workers is crucial. Training programs should cover hazard recognition, the proper use of equipment and personal protective gear, how to operate portable electric tools, emergency procedures, and the importance of reporting potential risks. Regular refresher courses should be conducted to reinforce safety practices.

Workplace Safety Signs - Workplace signs are an effective way to communicate hazards and safety information to workers. These include warning, danger, caution, emergency, and instructional signs. Proper placement and clear messaging are key to ensuring that these signs are noticed and understood.

Personal Protective Equipment (PPE) - Ensuring the availability and proper use of personal protective equipment (PPE) is essential. Construction workers should be provided with appropriate gear, such as hard hats, safety goggles, gloves, and high-visibility vests. Employers must enforce the use of PPE and regularly inspect it for damage or wear.

Regular Equipment Inspections - Frequent inspections of machinery, tools, and equipment are necessary to identify any defects or malfunctions. Prompt maintenance and repairs should be carried out regularly. Workers should also be encouraged to report any observed issues with equipment to prevent potential accidents.

Hazard Identification and Reporting - Creating a culture of hazard identification and reporting is essential. Workers should actively participate in identifying potential hazards and reporting them to supervisors. Encouraging open communication channels and fostering a non-punitive approach to reporting will help create a safer work environment.

FAQs

What are the main causes of deaths and injuries on scaffolds?

The main causes of deaths and injuries on scaffolds are falls, scaffold collapses, and being struck by falling objects. Falls occur when proper fall protection systems, such as guardrails or harnesses, are not in place or used correctly. Scaffold collapses often result from improper assembly, overloading, or use on unstable surfaces. Additionally, workers below scaffolds are at risk of being struck by tools or materials that are not properly secured.

What is one of the most common ways in which workers get hurt around machines?

One of the most common ways workers get hurt around machines is by getting caught in or struck by moving parts. This often occurs when proper machine guards are not in place or when workers bypass safety mechanisms. Contact with rotating, cutting, or shearing parts can lead to serious injuries, including amputations, fractures, and crushing injuries.

How many categories of struck-by hazards are there?

There are four categories of struck-by hazards: struck-by flying objects, struck-by falling objects, struck-by swinging objects, and struck-by rolling objects. Each category represents a different type of impact that can cause injury, whether from tools or materials being dropped, machinery parts that become airborne, or vehicles moving on a job site.

When would working with machinery be a common type of caught-in and caught-between hazard?

Working with machinery becomes a common type of caught-in and caught-between hazard when workers are exposed to moving parts without proper safeguards, or when machines start unexpectedly during maintenance or repair. For example, a worker might be caught in conveyor belts, gears, or rollers if the machinery is not properly shut down and locked out.

Which types of objects can contribute to caught-in or caught-between incidents?

Objects that can contribute to caught-in or caught-between incidents include heavy machinery, collapsing structures, materials being moved or hoisted, and unsecured equipment. Workers can be caught between two large objects, such as vehicles and walls, or between the moving parts of machinery, leading to serious injuries or fatalities.