accessibilityHazard

Definition

A characteristic of the described resource that is physiologically dangerous to some users. Related to WCAG 2.2 guideline 2.3.

Examples

Example 1 — EPUB 3

<meta property="schema:accessibilityHazard">flashing</meta>
<meta property="schema:accessibilityHazard">noMotionSimulationHazard</meta>
<meta property="schema:accessibilityHazard">unknownSoundHazard</meta>

Example 2 — EPUB 2

<meta name="schema:accessibilityHazard" content="flashing"/>
<meta name="schema:accessibilityHazard" content="noMotionSimulationHazard"/>
<meta name="schema:accessibilityHazard" content="unknownSoundHazard"/>

Example 3 — Audiobooks

"accessibilityHazard": [
   "flashing",
   "noMotionSimulationHazard",
   "unknownSoundHazard"
]

Example 4 — HTML with RDFa

<p><strong>Warning</strong>: <span
property="accessibilityHazard">flashing</span> 
in this video may cause seizures in some 
individuals.</p>

Example 5 — HTML with microdata

<p><strong>Warning</strong>: <span
itemprop="accessibilityHazard">flashing</span> 
in this video may cause seizures in some 
individuals.</p>

Values

The following values are used to identify potential hazards (or the lack thereof) so that users with such sensitivities know what to expect in advance. For more information, refer to the definition page for each.

Hazards

No Hazards

Unknown Hazards

Frequently Asked Questions

Do I need to specify the status of every type of hazard?

Yes, if you do not specify the status (present, not present, or unknown), then users cannot be sure if you have checked the publication. They will likely be informed that no information about the hazards is available.

Just because you know a publication does not present any hazards does not mean users will assume the same.

Is it better to use none or unknown than specify that each type of hazard is not present or is not known?

There is no technical difference between the two, so both options are fine.

Publishers might choose to avoid the none value, however, since it is not possible to anticipate if new hazards could be added in the future.

Conversely, it is simpler to temporarily set the unknown while waiting on an accessibility evaluation than record each possible hazard as unknown.