Short answer

• Rigging equipment fails mainly from mechanical damage (abrasion, cuts, kinking, broken wires), overload/overstress (including shock loads), corrosion/chemical or heat damage, fatigue from repeated bending, improper selection/installation or repairs, and human factors (poor inspection, incorrect rigging practices). These causes are well documented by OSHA, HSE and industry guidance. (OSHA.gov)

Why each cause leads to failure (brief)

• Overload/overstress: exceeding the rated working load shortens life or produces immediate failure (stretching, bending, fracture). (OSHA.gov)
• Mechanical damage and abrasion: cuts, snags, crushed strands or kinks create stress concentrations that cause rapid fatigue and local breaks. (OSHA.gov)
• Corrosion/chemical/heat damage: removes metal or degrades fiber, reducing strength and enabling brittle or ductile failure. Internal corrosion can be hidden and catastrophic. (IMCA-int.com)
• Fatigue from bending/rotation: repeated flexing (over sheaves, drums, around corners) causes wire or fiber breakage over time. (cptc-china.com)
• Improper selection/installation/repair: wrong sling type, undersized fittings, improper clips/splices or amateur repairs produce weak points. (OSHA.gov)
• Human/inspection failures: missed pre-use checks, inadequate periodic exams, poor documentation or training let defects remain in service. (OSHA.gov)

How to mitigate — practical, prioritized steps

1. Select the right equipment

• Match sling/hardware type (wire rope, chain, synthetic, webbing) to the load, environment (chemicals, heat, salt water), and lift method. Use manufacturer specs and applicable standards. (OSHA.gov)

2. Respect ratings and avoid overloads

• Never exceed marked working load limits (WLL). Apply appropriate rigging practices (sling angles, hitch types) and calculate effective loads (sling angle increases tension). Markings must remain legible. (OSHA.gov)

3. Inspect and maintain rigorously

• Pre-use (daily/shift) visual checks by a competent person plus documented periodic and thorough examinations (frequency per service conditions — monthly, quarterly, annually, or as required by regulation). Remove equipment meeting rejection criteria (broken wires, cuts, melted/charring, distortion, significant wear). (OSHA.gov)

4. Follow documented removal/rejection criteria

• Use regulatory and standard thresholds (e.g., broken wire counts for wire rope, percent wear for chain links, visible damage for synthetic slings); remove from service immediately when criteria met. (OSHA.gov)

5. Control environment and corrosion

• Store dry and protected, apply compatible lubricants/coatings for wire rope, avoid corrosive atmospheres or select corrosion-resistant materials (galvanized/stainless). Monitor for hidden/internal corrosion in ropes where applicable. (mazzellacompanies.com)

6. Avoid shock loads and improper handling

• Prevent shock/impact loading (snatch loads), avoid running wire ropes over undersized sheaves, prevent kinking, bending around inappropriate radii, and never pull slings through tight openings. Use proper pads/protectors over edges. (cptc-china.com)

7. Use correct end fittings, blocks, and protective measures

• Ensure fittings have equal or greater breaking strength than the sling, free of sharp edges, and are correctly sized/installed (clips, thimbles, hooks). Proof-test custom or repaired items as required. (OSHA.gov)

8. Training, competence and procedures

• Train riggers and inspectors on selection, rigging, inspection criteria and safe procedures; designate competent/qualified persons for inspections and lift planning; require documented lift plans for critical lifts. (OSHA.gov)

9. Recordkeeping and traceability

• Keep inspection records, proof-test reports and certificates for wire ropes and custom hardware; tag slings and chains with capacity and inspection dates. This aids monitoring and retirement decisions. (OSHA.gov)

10. When in doubt—remove from service and test

• If a defect is suspected or inspection is inconclusive, remove the item, have it assessed by a qualified person, and proof-test repaired or re-used equipment before returning to service. (OSHA.gov)

Quick rejection checklist (common, immediate reasons to remove)

• Synthetic slings: melting, charring, acid/caustic burns, snags, broken/worn stitches. (OSHA.gov)
• Wire rope: kinks, birdcaging, significant corrosion, heat/electric arc damage, the regulatory broken-wire counts, damaged end fittings. (OSHA.gov)
• Chains/hooks/shackles: bent/twisted/stretching, excess wear beyond tabulated allowable, cracked or deformed components. (OSHA.gov)

If you manage a rigging program (recommended baseline)

• Written procedures (selection, inspection, repair/retire criteria). (OSHA.gov)
• Competent inspector program with documented inspections and tags. (certifiedslings.com)
• Training and periodic refresher for riggers and inspectors. (OSHA.gov)
• Spare certified slings/hardware so damaged items are not used temporarily. (OSHA.gov)

If you want, I can:

• Provide a printable pre-use inspection checklist tailored to wire rope, chain, synthetic web slings or shackles/hooks; or
• Summarize specific OSHA/ASME/HSE removal criteria into one-page charts for your toolbox.

Sources (selection of authoritative guidance)

• OSHA — Rigging equipment (29 CFR 1926.251) and related standards for slings, shackles, and wire rope inspections. (OSHA.gov)
• OSHA eTool on ropes, chains and slings (selection, use, and removal criteria). (OSHA.gov)
• HSE (UK) — Thorough examinations and guidance on lifting equipment and wire rope hazards. (HSE.gov.uk)
• Industry safety notices/case reports (IMCA) and manufacturer guidance on wire rope corrosion and failures. (IMCA-int.com)

Would you like a one-page pre-use inspection checklist for a particular type of rigging (wire rope, chain, synthetic sling or shackles/hooks)? I can format it for printing.