What Is Signal Word
A signal word is one of two standardized terms on a Globally Harmonized System (GHS) label that communicates hazard severity: either "Danger" or "Warning." Danger indicates more severe hazards; Warning indicates less severe ones. OSHA requires these exact terms on all chemical labels in U.S. workplaces under 29 CFR 1910.1200.
Danger vs. Warning
The distinction matters operationally. "Danger" appears on labels for acute toxins, carcinogens, reproductive hazards, and chemicals that cause severe skin burns or eye damage. "Warning" covers skin irritants, eye irritants, respiratory sensitizers, and less acute health effects. In practice, a bottle of drain cleaner gets "Danger" because it causes severe chemical burns. A spray cleaner causing mild respiratory irritation gets "Warning."
Both signal words must appear directly on the label in a specific format: English language, at least 7-point font for workplace labels, above the hazard statement. The signal word anchors the label visually and tells workers immediately whether they need different handling procedures.
Regulatory Requirements
OSHA's Hazard Communication Standard mandates signal words on all chemical containers in workplaces. The rule applies to manufacturers, distributors, and employers. In your facility, every chemical stored on-site must have a label with the correct signal word. Safety audits routinely check this compliance point. Missing or incorrect signal words can result in OSHA citations ranging from $10,000 to $15,000 per violation.
For homeowners, signal words matter less directly but appear on pesticides, pool chemicals, and drain cleaners. Recognizing "Danger" tells you to use gloves, ventilate, and keep children away. "Warning" still requires caution but suggests lower risk.
Practical Application
- Train staff to scan signal words before handling any chemical. This takes 2 seconds and prevents most chemical exposure incidents.
- Use signal words to establish storage zones. "Danger" chemicals may require locked cabinets; "Warning" chemicals need secure shelving.
- Include signal word in emergency response plans. If someone is exposed to a "Danger" chemical, emergency protocols activate immediately.
- During safety audits, verify signal words match the Safety Data Sheet (SDS) for every container. Mismatches indicate labeling errors needing correction.
- For fire safety planning, note that some "Danger" chemicals are also flammable, requiring specific storage distance from ignition sources.
Common Questions
- What if a label is faded or unreadable? Relabel immediately using GHS-compliant labels. Keep the original SDS on file. Do not guess at the hazard level.
- Can I create my own signal words? No. OSHA requires the exact terms "Danger" or "Warning" only. Custom labels violate the standard.
- Do older chemical labels with "Caution" or "Poison" still count? No. All labels must comply with GHS standards. Phase out pre-2016 labels during your next inventory cycle.