15 Common Workplace Caution Signs: Hazards, Meanings, and Safety Compliance

OSHA (29 CFR 1910.145) and ANSI Z535 standards govern safety signage. Key caution signs (yellow/black) warn of potential hazards requiring awareness.

1. Wet Floor / Slippery Surface: Spills, cleaning, weather. Prevent slips/falls.
2. Electrical Hazard: Exposed conductors, live panels, temporary wiring.
3. High Voltage: >600V equipment, substations, overhead lines.
4. Men Working / Workers Above: Overhead hazards (falling tools, debris).
5. Falling Objects: Construction zones, warehouses, scaffolding.
6. Excavation / Trenching: Cave‑in risk, underground utilities, atmospheric hazards.
7. Compressed Gas: Cylinder storage/use; flammable, oxidizer, toxic, asphyxiant hazards.
8. Forklift / Powered Industrial Truck Traffic: Pedestrian‑vehicle interaction zones.
9. Biohazard: Infectious materials (BSL‑2+ labs, medical waste, sharps).
10. Hearing Protection Required: >85 dBA TWA; designated areas.
11. Respiratory Protection Required: Dust, fumes, vapors, gases exceeding PELs.
12. Danger – Keep Out / Authorized Personnel Only: Confined spaces, high‑risk machinery, radiation areas.
13. Confined Space: Permit‑required; hazards: O₂ deficiency, toxics, engulfment.
14. Laser Radiation: Class 3B/4 lasers; eye/skin hazard; controlled area.
15. Chemical Hazard / Corrosive: Acids, bases, oxidizers; PPE requirements.

Sign Design Principles (ANSI Z535.4)

• Signal word: CAUTION (yellow) for minor/moderate injury risk; WARNING (orange) for serious; DANGER (red) for life‑threatening.
• Pictogram + concise text + safety instructions.
• Placement: visible, at eye level, before hazard encounter.
• Maintenance: clean, legible, replaced when faded/damaged.

Effective signage is one layer of the hierarchy of controls (elimination → substitution → engineering → administrative → PPE).