Skip to main content

Developed and maintained by the NFCC


Unstable ground

Hazard Knowledge

Depending on the waste site involved, ground conditions can become unstable for many reasons:

  • Landfill sites - deep-seated fires, burning away waste deep under the crust, can create cavernous areas, resulting in underground voids appearing with little or no warning. These voids present a significant hazard to plant operators as well as to responding fire and rescue service personnel.
  • Illegal waste sites - as these sites are unlikely to have designated hard standing or purpose-made vehicle routes, ground conditions can quickly deteriorate as a consequence of firefighting operations and plant movement
  • General wear and tear and poor maintenance of existing roadways and waste storage areas, especially under large areas of stacked waste
  • Damage to concrete storage areas due to the intense heat created by the waste fire over many days

When working on landfill sites, constant observation of the waste surface should be maintained to spot any dipping; this may indicate subsidence and possible collapse into unidentified voids.