What must be done for safety when working in trenches?

When working in trenches, proper shoring is essential for safety because it prevents the walls of the trench from collapsing, which can lead to serious injuries or fatalities for workers inside. Shoring involves supporting the sides of the trench with materials such as wooden planks or metal supports to create a stable working environment. The Occupational Safety and Health Administration (OSHA) regulations emphasize that trenches deeper than five feet must be protected against cave-ins. Proper shoring techniques significantly reduce the risk associated with trench work and are critical for ensuring the safety of all personnel involved.

While using a harness, wearing a hard hat, and working only during daylight have their own safety advantages, they do not address the specific hazards associated with trench collapses, which is the primary concern when working in these environments. Hence, shoring is the most critical safety measure when it comes to trench work.