Jobsite Safety and Personnel Supervision
Rules and enforcement
Arizona operates a state OSHA plan (ADOSH) enforcing 29 CFR 1926 for construction. Know the Focus Four: falls, struck-by, caught-in/between, and electrocution. Fall protection is required at 6 feet in construction. Ladders must extend 3 feet above the landing and be set at a 4:1 angle; scaffolds require guardrails or personal fall protection at 10 feet. Excavations 5 feet or deeper require a protective system, with a competent person inspecting daily, spoil kept at least 2 feet back from the edge, and ladder access once the trench reaches 4 feet. Electrical work requires GFCI protection, lockout/tagout, and clearance from overhead lines.
Supervision
The competent person identifies hazards and has authority to take corrective action; the qualified person has recognized training and authority for a specific task, such as designing a trench shield. Supervisors run toolbox talks, enforce PPE, apply a disciplinary program, and document inspections. Report a fatality within 8 hours and an in-patient hospitalization, amputation, or loss of an eye within 24 hours. Heat illness prevention is a serious Arizona issue: water, rest, shade, and gradual acclimatization for new workers.
Traps
- Applying the 6-foot fall trigger to scaffolds (10 feet) or to ladders.
- Assuming a trench is safe without a competent person's inspection, especially after rain.
- Treating PPE as a substitute for engineering controls such as guardrails or shoring.
Worked example: to reach a 24-foot working height, set the ladder base 6 feet from the wall (24 ÷ 4) and extend the top 3 feet past the landing - specify a 27-foot extension ladder.