3.2 Focus Four Hazards

Relevance to the NC GC Exam

The "Focus Four" hazards are foundational to construction safety. The NC GC exam tests your ability to identify these hazards, know the specific thresholds for protection (such as the 6-foot rule for falls), and understand the required mitigation strategies. Questions frequently present scenarios and ask for the appropriate hazard control. Recognizing these four categories and their respective abatement strategies is essential not just for passing the exam, but for successfully managing any active construction site in North Carolina.

The Focus Four Overview

OSHA's Focus Four hazards (sometimes called the Fatal Four) account for more than half of all construction worker fatalities. They are:

1. Falls
2. Struck-By
3. Caught-In or -Between
4. Electrocution

General Contractors must implement training, safety equipment, and rigorous site management to mitigate these specific risks. A comprehensive safety plan must explicitly address each of these four categories.

1. Falls

Falls are consistently the leading cause of death in the construction industry. OSHA requires that fall protection be provided at elevations of six feet in the construction industry. This is a critical number to remember. It differs from general industry (4 feet) and scaffolding (10 feet).

Fall protection systems generally fall into three primary categories:

• Guardrail Systems: The standard guardrail consists of a top rail, midrail, and toe board. The top edge height of top rails must be 42 inches (plus or minus 3 inches) above the walking/working level. Midrails must be installed at a height midway between the top edge of the guardrail system and the walking/working level. Toe boards are required to prevent objects from falling onto workers below.
• Safety Net Systems: When used, safety nets must be installed as close as practicable under the walking/working surface on which employees are working, and never more than 30 feet below such level. They must be drop-tested on-site after installation.
• Personal Fall Arrest Systems (PFAS): These consist of an anchorage, connectors, and a full-body harness. (Body belts are no longer permitted for fall arrest). Anchorage points used for personal fall arrest systems must be capable of supporting at least 5,000 pounds per employee attached, or be designed and installed under the supervision of a qualified person as part of a complete system that maintains a safety factor of at least two.

Furthermore, employers must ensure that holes (including skylights) that are more than 6 feet above lower levels are protected by covers, guardrail systems, or personal fall arrest systems. Floor hole covers must be color-coded or marked with the word "HOLE" or "COVER" to provide warning of the hazard, and must be able to support, without failure, at least twice the weight of employees, equipment, and materials that may be imposed on the cover at any one time.

2. Struck-By Hazards

Struck-by injuries are produced by forcible contact or impact between the injured person and an object or piece of equipment. In construction, these are typically categorized as struck-by flying object, falling object, swinging object, or rolling object.

• Vehicles and Heavy Equipment: Workers must wear high-visibility reflective clothing when working near traffic or moving heavy equipment. Equipment must have functional backup alarms. If the alarm is broken or inaudible over surrounding noise, a spotter must be used to direct the operator.
• Falling Objects: When employees are required to work in areas where there is a danger of falling objects, they must wear hard hats. Toe boards, screens, or guardrails must be erected to prevent objects from falling to lower levels. When working at height, tools should be tethered, and materials must be secured from wind or accidental displacement.
• Flying Objects: Power tools and tasks like grinding, chipping, nailing, and welding produce dangerous flying debris. Appropriate face and eye protection (safety glasses with side shields, face shields) must be utilized by the operator and anyone working in the immediate vicinity.

3. Caught-In or -Between Hazards

These injuries result from a person being squeezed, caught, crushed, pinched, or compressed between two or more objects, or between parts of an object. This category includes trench cave-ins, being pulled into moving machinery, or being crushed between equipment and a solid wall.

• Excavations and Trenches: Cave-ins are the most feared caught-in hazard and are highly lethal due to the immense weight of soil. Any trench 5 feet or deeper requires a protective system (sloping, shoring, or shielding) unless the excavation is made entirely in stable rock. To prevent materials from falling in and causing a caught-in hazard, spoils (excavated dirt) must be kept at least 2 feet back from the edge of the trench.
• Machinery Guarding: Never remove safety guards from power tools or equipment. Moving parts like belts, pulleys, gears, chains, and shafts must be properly guarded to prevent loose clothing, lanyards, or limbs from being pulled into the mechanism.
• Barricading Swing Radiuses: Cranes, excavators, and other heavy equipment have a rotating superstructure. The swing radius must be barricaded to prevent workers from walking into the blind spot and being crushed between the heavy counterweight and fixed objects like walls, other machines, or building columns.

4. Electrocution Hazards

Electricity represents a serious unseen danger on construction sites. The major types of electrocution incidents involve contact with overhead power lines, contact with energized sources (live parts, damaged cords), and improper use of extension cords.

• Overhead Power Lines: Equipment such as cranes, forklifts, ladders, and scaffolding must maintain a minimum safe clearance of 10 feet from uninsulated overhead power lines carrying up to 50kV. For lines over 50kV, the distance increases. Always assume lines are live and uninsulated unless verified by the utility company.
• Ground-Fault Circuit Interrupters (GFCI): GFCIs are fast-acting circuit breakers designed to shut off electric power in the event of a ground-fault within as little as 1/40 of a second. GFCIs must be used on all 120-volt, single-phase, 15- and 20-ampere receptacles at construction sites that are not part of the permanent wiring of the building or structure.
• Lockout/Tagout (LOTO): Before performing service or maintenance on equipment where unexpected energization or startup of the equipment could cause injury, the equipment must be isolated from its energy source and locked or tagged out. This prevents a machine from being accidentally turned on while a worker has their hands inside it.