Which of these is an example of a vertical standard? Please select all that apply. Excavation workers must be protected from cave-ins. When welding, a fire watch must be maintained for 30 minutes past the time of welding. Ladders must always extend three feet past the working surface. An iron worker is placing steel 30 feet up and is wearing a full body harness tied off to an anchor point with a lanyard. PPE is required to protect against face, hand, and eye injuries.