Uncontrolled Structural Collapse
HighThe primary hazard in structural demolition is uncontrolled or premature collapse of building elements before planned demolition sequence intends. As load-bearing walls, columns, floors, and beams are removed, remaining structure must support redistributed loads with compromised strength. Buildings may have hidden structural damage, corrosion, or defects not apparent during initial assessment. Previous building modifications may have altered load paths in undocumented ways. Timber structures suffer degradation from rot and insect damage reducing structural capacity. Concrete structures may have hidden reinforcement corrosion or construction defects. When critical structural elements are removed in incorrect sequence, sudden collapse can occur crushing workers beneath or adjacent to the structure. Partially demolished buildings are inherently unstable and subject to collapse from wind loading, vibration from equipment, or progressive failure of weakened members.
Consequence: Multiple worker fatalities from being trapped or crushed under collapsed structure sections, serious crush injuries requiring extended hospitalisation, damage to adjacent buildings from collapse impact and debris projection, and public safety incidents if collapse extends beyond site boundaries.
Being Struck by Falling Materials and Debris
HighDemolition creates constant risk of materials falling from height as structures are progressively dismantled. Roof materials, cladding, bricks, concrete sections, timber members, and fixtures fall or are pushed from height during demolition operations. Mechanical demolition using excavators causes materials to fall unpredictably as structures are pulled or crushed. Workers on ground level, on elevated work platforms, or on adjacent building sections face impact hazards from falling debris. Materials can bounce or slide down debris piles striking workers who believe they are in safe positions. Wind can cause unstable materials to fall unexpectedly. Small items including bricks, tiles, and fixings falling from significant height have sufficient energy to cause fatal head injuries. Controlled material dropping down chutes or designated drop zones presents risks if exclusion zones are not properly maintained and monitored.
Consequence: Fatal or serious head injuries despite hard hat use due to impact forces from falling materials, crush injuries to torso and limbs, fractures and soft tissue damage, and multiple casualties if collapse sends debris over wide area.
Falls from Height During Demolition Activities
HighDemolition work frequently requires access to roof level, upper floors, and elevated positions to remove materials and conduct progressive top-down demolition. Unlike intact buildings, demolition sites have compromised floor edges, removed guardrails, unstable working surfaces, and holes in floors and roofs. Workers removing roof sheeting walk on fragile surfaces that may collapse. Upper floor slabs may be weakened by removed supports. Roof trusses become unstable as bracing and connections are removed. Access equipment including ladders and scaffolding may be poorly positioned on uneven demolition debris. Workers carrying materials or tools have reduced ability to maintain three points of contact on access equipment. Working alone during demolition means fall victims may not receive timely rescue. The combination of elevated work, unstable surfaces, and absence of intact fall protection systems creates extreme fall risk.
Consequence: Fatal injuries from falls exceeding 3 metres onto concrete floors or debris piles, head trauma and spinal injuries, fractures to multiple body parts, and impalement on protruding reinforcement or structural members.
Asbestos and Hazardous Material Exposure
HighBuildings constructed before 1990 commonly contain asbestos in various forms including bonded asbestos in roof sheeting and wall cladding, friable asbestos in insulation and fire protection, vinyl floor tiles and backing, pipe lagging, gaskets, and textured ceiling coatings. Mechanical demolition crushes and pulverises these materials releasing respirable asbestos fibres. Even buildings constructed after asbestos bans may contain asbestos in imported materials or from partial renovations using old stock. Other hazardous materials in older buildings include lead-based paints, PCBs in electrical equipment and sealants, synthetic mineral fibres in insulation, mercury in switches and fluorescent lights, and residual chemicals in industrial buildings. Disturbing these materials during demolition creates serious acute and chronic health hazards.
Consequence: Asbestos-related diseases including mesothelioma and lung cancer developing 20-40 years after exposure, lead poisoning causing neurological damage, acute toxic exposure to PCBs and mercury, regulatory prosecution and work prohibition orders, expensive decontamination and remediation, and long-term health monitoring obligations for exposed workers.
Underground and Overhead Service Strikes
HighDemolition sites contain numerous underground services including electrical cables, gas mains, water pipes, telecommunications cables, sewer lines, and stormwater drainage. Service plans are often inaccurate for older buildings, services may have been modified over building life, and abandoned services may remain energised. Excavator buckets or demolition equipment can strike buried services during foundation removal or ground clearance. Overhead power lines may be present or pass close to demolition area presenting electrocution risk when materials are lifted or when excavators operate with extended booms. Live electrical services within buildings may remain energised if isolation is inadequate. Gas services can release flammable gas if ruptured during demolition. Water main strikes cause flooding and service disruption. Telecommunications cable damage causes widespread service outages.
Consequence: Electrocution fatalities from contact with underground or overhead power lines, gas explosions and fire from ruptured gas services, flooding and property damage from water main strikes, extensive service disruption affecting thousands of customers, regulatory investigation, and substantial financial penalties and compensation.
Mobile Plant and Equipment Interaction Hazards
HighDemolition relies heavily on mobile plant including excavators with various attachments (buckets, pulverisers, grapples, shears), skid-steer loaders, excavators, tip trucks, and mobile cranes. These machines operate in congested and constantly changing environments with limited visibility, unstable ground surfaces, proximity to workers on foot, and interaction with partially demolished unstable structures. Excavator operators have restricted visibility around and behind machines. Workers on foot can be struck by moving plant, caught between plant and structures, or run over by reversing vehicles. Excavator booms can strike workers when slewing. Tipping trucks reversing to tip debris present backing hazards. Ground surfaces weakened by removed services or basements can collapse under plant weight. Overhead contact with power lines during boom operation causes electrocution.
Consequence: Fatal crushing injuries from being struck by or run over by mobile plant, electrocution from overhead power line contact, serious injuries from being caught between plant and structures, plant rollover injuries if ground collapses, and multiple casualties if plant strikes crowds of workers.
Noise, Dust, and Vibration Environmental Impacts
MediumDemolition generates extreme noise levels from concrete breaking, crushing, and materials dropping, with levels frequently exceeding 100dB(A). Prolonged exposure causes permanent hearing loss to workers. Noise also impacts surrounding residents and businesses potentially breaching local council environmental regulations. Dust generation during demolition is substantial, containing silica from concrete and masonry, asbestos fibres if asbestos removal was inadequate, lead and other heavy metals from paint particles, and general particulate matter. Uncontrolled dust creates respiratory hazards for workers and off-site air quality impacts. Vibration from heavy impact, drop-ball demolition, or large materials falling transmits through ground affecting adjacent structures, sensitive equipment, and causing nuisance to neighbours. Historical buildings and structures with existing cracks are particularly vulnerable to vibration damage.
Consequence: Permanent noise-induced hearing loss in workers, council enforcement action and work stop orders for environmental breaches, complaints and disputes with neighbours and businesses, damage to adjacent structures from vibration, respiratory disease from dust exposure including silicosis, and project delays from noise and dust complaints.
