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Underground utility incidents

Hazard Knowledge

Underground utility incidents may be indicated by damaged or displaced covers (for example manhole or inspection covers) or paving slabs, resulting in:

  • Open pits or cavities
  • Exposed utilities
  • Projectile hazards


High-voltage underground cables are insulated with oil or gas under pressure. Overheating can lead to fire and an increase in the oil or gas pressure. This pressure can result in covers or paving slabs at ground level being damaged or displaced (blown-off).

These incidents may present additional hazards, such as toxic fumes spreading along cable ducting, potentially into nearby properties.

Bituminous insulation may also be damaged, resulting in exposed electrical cables and equipment. This could create a risk of electrocution to the public, responding fire and rescue service personnel or other agencies.


Gas leaks underground may also result in an explosion or fire, if ignited by an electrical fault or an above ground ignition source.


Storm rain covers may be displaced due to storms, flooding or burst water mains.