A 27-year-old laborer died after being trapped in soil over his head as a result of a trench cave-in. The laborer was digging out the bottom of the trench to expose a drain pipe. On one side of the trench was a retaining wall. The other side was a dirt wall which was part of a hillside.

When the collapse occurred, another worker had been pulling up buckets filled with the spoil, placing it on the hillside above the trench wall as well as on the other side of the excavation. Eventually the hillside collapsed, burying the laborer. The hillside that collapsed was not shored or otherwise protected from earth movement. The soil in the area had recently been disturbed by an earthquake. There was no competent person on site to check the soil and excavation. No initial hazard assessment had been performed. The laborer had received no training from the company.

What went wrong? What caused this fatality? How could this accident have been prevented? Provide at least three recommendations.