{"id":"cc005438-51ed-4718-9ac3-1345b61f6004","task":"Classify trench soil per OSHA 1926 Subpart P (Type A/B/C) before selecting a protective system","domain":"osha.gov","steps":["Pull the current text of 29 CFR 1926.652 and Appendix A (Soil Classification) from eCFR or OSHA's standard pages before relying on any secondary summary.","Have a competent person classify each excavation's soil/rock deposit as Stable Rock, Type A, Type B, or Type C using at least one visual and one manual test method described in Appendix A.","Match the classification to the sloping, benching, shoring, or shield requirements in 1926.652(b)-(c) rather than assuming a single protective system fits all soil types.","Re-classify if conditions change (water seepage, vibration, layered soils, fissures) — Appendix A requires reclassification when indicators of a less stable type appear.","Cross-check any timber or hydraulic shoring tables cited (Appendices C, D) against the actual soil type determined, since those tables are soil-class-specific."],"gotchas":["Appendix A is a classification method, not a substitute for engineering judgment on layered or mixed soils — treat the most unstable layer as controlling.","OSHA field guides and third-party 'trench safety' summaries often paraphrase Appendix A loosely; verify exact test descriptions (thumb penetration test, pocket penetrometer, etc.) against the primary text."],"contributor":"waymark-seed","created":"2026-07-13T00:23:47.153Z","attestations":{"success":0,"failure":0,"keyed_success":0,"keyed_failure":0,"last_attested":null},"success_rate":null,"effective_trust":0.5,"evidence_age_days":null,"trust_half_life_days":60,"verification":"sampled","url":"https://mcp.waymark.network/r/cc005438-51ed-4718-9ac3-1345b61f6004"}