Originally Published MDDI April 2004

Product Development Insight



David Warburton

On an ANSI-compliant safety label, the signal word panel indicates the degree of hazard. The panel has three components: the signal word itself, the background color, and the safety alert symbol. ANSI Z535.4 defines the signal words as follows:

“4.13.1 DANGER: Indicates an imminently hazardous situation which, if not avoided, will result in death or serious injury. This signal word is to be limited to the most extreme situations.”

“4.13.2 WARNING: Indicates a potentially hazardous situation which, if not avoided, will result in death or serious injury.” 
“4.13.3 CAUTION: Indicates a potentially hazardous situation which if not avoided, may result in minor or moderate injury. It may also be used to alert against unsafe practices.”

ANSI Z535.4 allows the use of the word CAUTION without the safety alert symbol for labels that warn against property or equipment damage only. The signal words DANGER and WARNING should never be used for labels warning against property damage unless there is a possibility of a commensurate human injury. 

Both the color of the signal word and the color of the background are defined in the standard. DANGER must be white on a red background, WARNING must be black on an orange background, and CAUTION must be black on a yellow background. The safety alert symbol, the triangle with the exclamation mark, indicates that a human injury hazard exists. 

The ANSI Z535.4 standard provides standardized translations in 17 languages of the three signal words. Depending on the export market for its medical devices, a manufacturer may choose to provide safety labels on the products in languages other than English. English is the only language required in the United States.

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