Explanation

The unknownSoundHazard value indicates that a publisher has not yet checked for sound hazards or is unsure whether some content might present a hazard.

Due to the current lack of clarity around sound hazards, this value is often used to indicate that it is not possible to determine any risks.

The unknownSoundHazard value must never be set together with the none, sound, or noSoundHazard values, as these values conflict.

The unknownSoundHazard value should not be set with the unknown value, as these values are redundant.

Examples

Example 1 — EPUB 3
<meta property="schema:accessibilityHazard">unknownSoundHazard</meta>
<meta property="schema:accessibilityHazard">noFlashingHazard</meta>
<meta property="schema:accessibilityHazard">nomotionSimulationHazard</meta>
Example 2 — EPUB 2
<meta name="schema:accessibilityHazard" content="unknownSoundHazard"/>
<meta name="schema:accessibilityHazard" content="noFlashingHazard"/>
<meta name="schema:accessibilityHazard" content="nomotionSimulationHazard"/>
Example 3 — Audiobooks
"accessibilityHazard": [
   "unknownSoundHazard",
   "noFlashingHazard",
   "nomotionSimulationHazard"
]

ONIX Mapping

The unknownSoundHazard value maps to ONIX list 143 code 25 ("Sound risk unknown").

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