OSHA Standard 29 CFR 1910.145, "Specifications for accident prevention signs and tags", provides specific instructions on when you should use a particular signal word:
- DANGER - indicates immediate danger and that special precautions are necessary.
- CAUTION - should be used only to warn against potential hazards or to caution against unsafe practices.
- WARNING - may be used to represent a hazard level between "Caution" and "Danger" subject to provisions in the Standard.
- Safety instruction signs - should be white, with a green panel with white letters. Letters on the white background should be black. They are used for general instructions and suggestions relative to safety measures.