Before workers enter a trench 6 feet deep, who must classify the soil and select an appropriate protective system?

Explanation

Section 1541.1 puts soil classification and the selection of a protective system on a competent person - defined as someone capable of identifying existing and predictable hazards AND authorised to take prompt corrective action, which is why the employer has to designate them. The other three are real participants who cannot carry the duty. The operator (a) may be the most experienced person on the crew and has no authority to stop the work. A registered professional engineer (b) enters where the excavation passes 20 feet or the system falls outside the appendices; below that the competent person may work from Appendix A. And a soils laboratory (d) can test a sample, while classification under Appendix A requires at least one visual and one manual analysis at the face, repeated as conditions change through the day.