Every tragic incident takes a toll far beyond statistics. Lives are lost, families are changed forever, and communities are shaken. When risks are visible but remain unaddressed, the cost can be more than financial, it is often measured in human lives.
For those of us working in investigations and safety, the priority must always be to learn. Not to blame. Not to assume. To examine what happened, reflect on why warning signs were missed, and share strategies to prevent recurrence.
Here are five recent incidents from the UK and Europe where hazards were visible but not acted upon in time, along with insights and actions that safety leaders can take away
Stonehaven Rail Derailment (Scotland, 2020)
Stonehaven Rail Derailment. Image Source - Sky News
On 12 August 2020, around 09:37 hrs, a passenger train travelling near Carmont (Stonehaven) derailed after striking debris from a landslip triggered by heavy rainfall. Three people died, six were injured. The train had been diverted back toward Aberdeen because of an earlier blockage and was travelling at 73 mph when the derailment occurred. The derailment involved multiple carriages leaving the track, colliding with infrastructure and scattering debris.
Investigators determined that the drainage system installed between 2011–12 had not been built to design specification, and subsequent modifications by Carillion were not properly documented or notified to designers. A bund (low earth bank) near the site altered water flow into the drainage trench, concentrating runoff into a steep slope that washed out ballast and track bed under heavy rain conditions. No controls such as speed restrictions for extreme weather were in place.
Insights for HSE leaders
• Post-installation verification and independent inspection of civil works are non-negotiable for safety-critical assets
• Any changes from original design must be formally documented, reviewed, and integrated into maintenance records
• Operational controls tied to environmental triggers (e.g. rainfall thresholds) are essential to limit exposure during extreme conditions
• Infrastructure and route control teams must be empowered with procedures, training, and decision authority to act when conditions deviate from normal
Turning insight into action
• Institute a formal verification process for newly constructed infrastructure before transferring into operations
• Deploy condition monitoring or sensors on drainage and slopes to detect ground movement or blockage early
• Develop triggers in operations systems to enforce speed restrictions in severe weather
• Integrate extreme weather response scenarios into route control exercises and training
Avonmouth Water Plant Explosion (England, 2020)
Avonmouth Water Plant Explosion. Image Source - BBC News
On 3 December 2020 at about 11:20 GMT, a silo containing biosolids at the Wessex Water site in Avonmouth exploded, killing four men (including a 16-year-old apprentice) and injuring one person.
Prior to the event, consultant reports from 2014–2015 had warned of a “perfect explosive mixture” potential and flagged deficiencies in the plant’s digesters, gas holders, and biogas infrastructure. Those reports explicitly named risk areas and recommended safety devices, but action on recommendations has been questioned.
Experts have speculated that hot work (e.g. drilling or grinding) may have been conducted on or near the silo without appropriate ignition control or gas monitoring. If air ingress occurred in the silo gas space, a flammable mixture could have been present, and ignition from sparks could have triggered the blast.
Investigations into criminal liability were closed in 2024 due to insufficient evidence.
Insights for HSE leaders
• Consultant and audit findings must be tracked, assigned ownership, and periodically reviewed until resolution
• Hot work in areas with potential flammable atmosphere must include strict ignition control, pre-check gas monitoring, and permit enforcement
• Process safety practices must be routinely reassessed as systems age, including ventilation, gas detection, and protective device maintenance
• Staff must feel empowered to question unsafe conditions and halt work if anomalous hazards appear
Turning insight into action
• Create a centralised system to log, track, and verify closure of audit or consultant recommendations
• Enhance permit-to-work procedures with required gas testing before and during hot work
• Verify presence, installation, and maintenance of safety devices (e.g. flame arresters) in gas systems
• Conduct internal safety culture audits and training on hazard recognition, reporting, and safe shutdown
Toddbrook Reservoir Near Collapse (England, 2019)
Toddbrook Reservoir Near Collapse. Image Source - The Guardian
In July 2019, unusually heavy rainfall damaged the Toddbrook Reservoir spillway, raising the risk of dam failure and forcing the evacuation of approximately 1,500 people. The concrete spillway, originally added in the 1960s, had known structural issues including thin slabs, inadequate drainage, and poor anchoring. Satellite data had already shown slight movement or distortion in 2018 and early 2019 preceding the event.
When excessive water reached the spillway, areas of the structure crumbled and failed, exposing weaknesses that had not been fully remediated. The deterioration was incremental but ultimately reached a tipping point under hydrologic stress.
Insights for HSE leaders
• Structural assets deteriorate over time; small changes in measurement data should trigger formal investigation
• Remote sensing (satellite, drone) data must feed into escalation frameworks, not remain siloed archives
• Underinvestment in maintenance is often a precursor to failure in aging infrastructure
• Rates of degradation and environmental stresses should shape inspection frequency and funding allocations
Turning insight into action
• Maintain up-to-date asset condition registers with risk priority assigned
• Define escalation thresholds for observed movement or distress signals that require urgent inspection
• Secure dedicated funding for preventive maintenance on high-hazard infrastructure
• Ensure executive oversight of deferred maintenance decisions
Grenfell Tower Fire (London, 2017)
Grenfell Tower Fire. Image Source - ABC News
On the night of 14 June 2017, a fire broke out in Grenfell Tower, spreading rapidly via combustible cladding and insulation. Seventy-two people lost their lives. The fire performance of the materials used had been questioned globally in prior incidents.
Regulatory frameworks did not ban certain types of cladding at the time; however, industry experts and previous high-rise fires had flagged the risks of aluminium composite panels (ACPs) in façade systems. Post-Grenfell inquiries revealed that manufacturers had internal awareness of fire risks.
Insights for HSE leaders
• Relying solely on compliance may leave emerging risks unaddressed — risk assessment must look beyond current regulation
• Procurement must demand independent fire performance validation and not accept self-certified claims blindly
• Building occupants and users often spot defects and issues first; their feedback must feed into risk management
Turning insight into action
• Periodically reassess building materials and safety of façades against evolving research
• Audit material supply chains and require third-party testing for critical products
• Create robust resident reporting channels and act promptly on concerns
• Perform scenario planning and drills for fire, smoke spread, and evacuation under abnormal conditions
Stresa Cable Car Disaster (Italy, 2021)
Stresa Cable Car Disaster. Image Source - NBC News
On 23 May 2021, a cable car travelling near Stresa plunged after its emergency brake — the ultimate safety fallback — had been manually disabled. Fourteen people died. Reports suggest the brake had been clamped to prevent nuisance engagement.
Because the brake was rendered ineffective, when the haul cable broke, the cabin had no mechanism to arrest the fall. This decision to disable a safety system compromised every occupant.
Insights for HSE leaders
• Safety systems should never be bypassed without rigorous review and formal approval
• Recurring maintenance issues disabling safety devices must escalate beyond frontline level
• Monitoring should detect disabled safety systems and trigger alerts or shutdowns
Turning insight into action
• Institute an escalation process for faults that compromise safety-critical systems
• Establish a just culture where workers can safely refuse or halt work when critical systems fail
• Implement alarms or automatic shutdowns when a safety device is disabled
• Conduct leadership walkthroughs emphasising that safety must not be compromised for convenience
Reflections for Senior Leaders
Across these cases, the hazards weren’t hidden mysteries. They were obvious, documented, or visible risks, defective drains, methane gas, aging infrastructure, combustible cladding, disabled brakes.
The lesson is clear: recognising a hazard is not enough. Organisations must:
• Investigate and act on early warnings.
• Maintain oversight of high-risk assets.
• Ensure safety systems are never bypassed.
• Build cultures where reporting and fixing issues outweigh convenience or cost pressures.
At COMET, we help organisations avoid these failures by moving from reactive fixes to structured, root cause learning. With digital tools for investigations, audits, and risk analysis, we make it easier to capture warnings, act decisively, and prevent repeat failures.
Questions to ask:
• Are near-miss reports and consultant recommendations investigated and are preventive actions treated with urgency?
• Can workers freely pause operations if a safety system is compromised?
• Do inspection budgets and maintenance programmes resist cost pressures?
• Do tracking systems verify that corrective actions are independently audited?
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Sources for further reading:
- Stonehaven Rail Derailment (Scotland, 2020)
- RAIB publishes report into fatal Stonehaven derailment - Railway-News
- Resilience of rail infrastructure: final report - GOV.UK
- Rail Accident Investigation Branch releases report on fatal derailment in Stonehaven - RailBusinessDaily
- Stonehaven derailment - Wikipedia
- Avonmouth Water Plant Explosion (England, 2020)
- BBC / HazardEx investigation: consultant reports warned of risk before explosion - HazardEx on the Net+1
- Avonmouth explosion (Wikipedia) - timeline and publicly known facts - Wikipedia
- ITV News: police drop manslaughter probe after Avonmouth blast - ITVX
- New details revealed about fatal Avonmouth explosion - The Bristol Cable
- Toddbrook Reservoir Near Collapse (England, 2019)
- Independent review: Toddbrook Reservoir incident (2019) - GOV.UK
- Canal & River Trust on independent reports and findings - Canal & River Trust
- Grenfell Tower Fire (London, 2017)
- Grenfell Tower Inquiry official documents - GOV.UK (Phase 2 publication) - BBC Feeds+1
- Grenfell Tower Inquiry reports and material - main inquiry website and linked documents - BBC Feed
- Stresa Cable Car Disaster (Italy, 2021)
- Stresa–Mottarone cable car crash overview and publicly documented facts - Wikipedia
- Stresa–Mottarone cable car crash overview and publicly documented facts - Wikipedia
Editor’s note
COMET was not involved in the investigation or management of any of the incidents described in this article. We have chosen these examples because they are well-documented, publicly available, and provide valuable learning opportunities for anyone working in safety, risk, and operational leadership. By reflecting on these events, we aim to encourage proactive thinking and help organisations strengthen their systems to prevent future harm.
