> For the complete documentation index, see [llms.txt](https://docs.os.uk/os-downloads/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.os.uk/os-downloads/resources/product-resources/end-of-life-product-documentation/os-detailed-path-network/os-detailed-path-network-technical-specification/code-lists/potentialhazardvalue.md).
# PotentialHazardValue
This attribute indicates that part or all of the RouteLink passes through an area that may pose an impediment to passage for users or a level of risk.
Only RouteLink features with the descriptiveTerm of ‘No Physical Manifestation’ or ‘Path’ are eligible to have the potentialHazard attribute populated. Values may be multiple if appropriate.
{% hint style="info" %}
This attribute is particularly relevant where a RouteLink feature has been provided with a descriptiveTerm of ‘Route Without Physical Manifestation’, as some legal rights of way may pass over problematic or even dangerous terrain and may need to be excluded from any route options.
{% endhint %}
For all other navigableLink features, this value is null.
Classification of hazardous terrain that may pose a risk or impediment to passage.
| Value | Description |
| ------------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| Boulders | The route passes through an area of boulders. |
| Cliff | The route passes over an area of cliffs. |
| Quarry Or Pit | The route passes through an active or disused excavation, for example, a pit or quarry. |
| Foreshore \* | The route passes through an area that is covered by the tide at normal High Tides in England and Wales and an area that is covered by the tide at normal Spring High Tides in Scotland.
Note that paths near the High Water Mark may also be covered when tides are higher than the marks that Ordnance Survey record – normal High Tides in England and Wales and Spring High Tides in Scotland.
|
| Marsh | The route passes through an area of marsh. |
| Mud | The route passes through an area of mud. |
| Sand | The route passes through an area of sand. |
| Scree | The route passes through an area of scree. |
| Shingle | The route passes through an area of shingle. |
| Spoil | The route passes through an area of deposited material. |
| Rock | The route passes over an area of surface rock. |
| Tidal Water | The route passes through an area of permanent tidal water. |
| Inland Water | The route passes through an area of permanent non-tidal water. |
\*Foreshore is added to all links that are intertidal.
---
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