Big Four Hazards in Construction #1. Falls When working 6 feet above the ground, or more, use personal fall arrest system (wear safety harness or install guardrails). When working on steepsloped roofs (greater than 4 in 12 pitch), wear a safety harness, install guardrails or safety net. When performing roofing work on low-sloped roofs (of less than 4 in 12 pitch), use personal fall arrest or warning line system and safety monitor. When working on scaffolds over 10 feet in height, install guardrail system, fully planked working surface and toe boards. #2. Electrical Don’t use worn or frayed power or extension cords. Always install GFCI at temporary power pole or by other means. Stay 10 feet away from energized power lines. Safe distance includes tools, equipment and employees. Check for inadequate wiring hazards. Nonmetallic sheathed cable should not be substituted for hard service extension cords. Ensure all power tools are grounded by having a grounding pin on attachment plug or by using equipment that is double insulated. Ensure that all extension cords are designed for hard or extra hard service and have a grounding pin on attachment plug. Double-Insulated Tools Hand-held tools manufactured with non-metallic cases are called double-insulated. If approved, they do not require grounding under the National Electrical Code. Although this design method reduces the risk of grounding deficiencies, a shock hazard can still exist. #3. Struck-By Always wear approved hard hat when working under potential falling debris hazards. When operating vehicles in reverse, activate backup alarm or use signal person. Use barricade around crane superstructures. Wear reflective vest when working near or in the vicinity of vehicular traffic. Ensure nail guns and other power tools have properly functioning safety devices. #4. Caught-In/Between Install trench boxes or slope side walls of trench. Use ladders in trenches that are over 4 feet deep for access and egress. Ensure stairways, ladders, ramps or other safe means of egress are provided. Keep spoil pile 2 feet away from edge of trench. Always have a competent person on site at trench constructions. The competent person must have knowledge of soil type, proper sloping techniques, knowledge of rules/OSHA standards for excavation and trenching; must have authority to take prompt corrective measures to eliminate existing and predictable hazards and to stop work when required. Ensure all power tools and equipment are properly guarded, including circular saws, air compressors and portable cement mixers. If you would like to receive interpretive guidance on this or any other OSH standard or topic, you can submit your questions using the Ask OSH web form, by e-mail to email@example.com or by calling 919-707-7876.