Which of the following is a requirement for all trenches over 5 ft deep?

The requirement that all trenches over 5 feet deep must have a ladder or exit every 25 feet is based on the safety standards established by the Occupational Safety and Health Administration (OSHA). These regulations are in place to ensure the safety of workers entering and exiting deep trenches or excavations.

Having a ladder or means of egress accessible every 25 feet is crucial because it provides a safe and quick escape route in the event of a collapse or emergency situation. This requirement mitigates the risk of suffocation or injury, as workers may panic or become immobilized if they cannot exit the trench promptly.

The other options, while relevant to safety in different contexts, do not specifically address this critical aspect of trench safety as outlined by OSHA. For example, while providing adequate lighting can enhance safety, it is not a specific requirement tied to the depth of a trench in the same way that an escape route is mandated. Similarly, using air monitoring devices is important in certain excavation situations, particularly where hazardous atmospheres might be present, but the stipulation about exits is fundamentally concerned with physical safety risks associated with trench collapses.