The top four causes of construction fatalities are: Falls, Struck-By, Caught-In/Between and Electrocutions.

Prevent Falls

• Wear and use personal fall arrest equipment.
• Install and maintain perimeter protection.
• Cover and secure floor openings and label floor opening covers.
• Use ladders and scaffolds safely.

Prevent Struck-By

• Never position yourself between moving and fixed objects.
• Wear high-visibility clothes near equipment/vehicles.

Prevent Caught-In/Between

• Never enter an unprotected trench or excavation 5 feet or deeper without an adequate protective system in place; some trenches under 5 feet deep may also need such a system.
• Make sure the trench or excavation is protected either by sloping, shoring, benching or trench shield systems.

Prevent Electrocutions

• Locate and identify utilities before starting work.
• Look for overhead power lines when operating any equipment.
• Maintain a safe distance away from power lines; learn the safe distance requirements.
• Do not operate portable electric tools unless they are grounded or double insulated.
• Use ground-fault circuit interrupters for protection.
• Be alert to electrical hazards when working with ladders, scaffolds or other platforms.

Source: osha.gov