The first element to consider when designing a product safety label is to determine the likelihood and severity of a potential injury if a person does not follow the instructions contained on the safety label or sign.

For product identification there are four Signal Words or Hazard Classifications used in the design of an ANSI Z535.4 2007 compliant safety label: “DANGER”, “WARNING”, “CAUTION” or “NOTICE”

When more than one hazard exists on a product it is permissible to use one label, provided the information addresses each hazard and the signal word selected is based on the greatest level of hazard.

The Safety Alert Symbol is used to warn of a potential personal injury hazard. This symbol is used in conjunction with the signal word or can be used alone. This symbol should be used on both product safety labels and in literature which can describe the potential hazard in greater detail.

Another change worthy of note is the clarification of the Safety Alert Symbol; use and respective colors and the incorporation of the ISO 3864-1 version. In the last revision, 2002, it only supplied a explanation of what the symbol should be and what it meant. This new revision (2007) on the other hand has taken a step further into clarifying when to use, how to use, what colors it should be, and also the option(s) that when used on the ANSI safety labels will be in compliance with ISO 3864-2.

Safety alert symbol. It is used to alert you to potential personal injury hazards. Obey all safety messages that follow this symbol to avoid possible injury or death.

The 2002 revision stated that the signal words for product safety labels were: DANGER, WARNING, CAUTION. Where CAUTION could be used for property-damage-only accidents when used without the triangle and exclamation mark.

DANGER: Indicates an imminently hazardous situation which, if not avoided, will result in death or serious injury. Safety Signs identified by the signal word DANGER should be used sparingly and only for those situations presenting the most serious hazards.

WARNING: Indicates a potentially hazardous situation which, if not avoided, will result in death or serious injury. Hazards identified by the signal word WARNING present a lesser degree of risk of injury or death than those identified by the signal word DANGER.

CAUTION: Indicates a hazardous situation, which if not avoided, could result in minor or moderate injury. It may also be used without the safety alert symbol as an alternative to “NOTICE”

NOTICE: is the preferred signal word to address practices not related to personal injury. The safety alert symbol should not be used with this signal word. As an alternative to “NOTICE”, the word “CAUTION” without the safety alert symbol may be used to indicate a message not related to personal injury.

Safety instructions or safety equipment location signs indicate general instructions relative to safe work practices, reminders of proper safety procedures, or the location of safety equipment.

Fire Related Safety Signs:
These signs do not have a signal word (header). If there is a message, the colors should be red background with white text of white symbol, whenever a symbol is used.

Directional Arrow Sign Panels:
arrows should be white on a colored background (black, red, green, or the same color as the text message)

ANSI has added this Annex E to provide guidance when selecting and determining which signal word to use to identify a hazardous situation.