Understanding hazard, harm, and the hazardous situation is fundamental to effective risk management for medical devices. Yet these concepts are often confused, particularly when teams map risks into an ISO 14971 compliant Risk Management File.
Getting them right matters. These definitions shape every part of the risk-management lifecycle, from design and development through to production, post-market surveillance, and eventual device retirement.
This article explains the key terms, how they relate to each other, and how manufacturers can apply them in a structured, lifecycle-long process.
Risk Management Is a Lifecycle Requirement
Manufacturers sometimes view risk management as a one-off activity, but under ISO 14971 and ISO/TR 24971, risk management must be integrated throughout the entire lifecycle of the device:
- Early design and development
- Verification and validation
- Manufacturing and process control
- Clinical use
- Post-market monitoring and surveillance
- Change management and continuous improvement
As your device evolves, new risks emerge, clinical use patterns shift, and design changes may introduce new hazards. Your risk documentation must evolve with it. This is why ISO 14971 emphasises risk management as a living system rather than a single event.
Key Definitions: Hazard, Harm, and Hazardous Situation
Hazard
A potential source of harm.
Harm
A physical injury, damage to health, or damage to property or the environment.
Hazardous situation
A circumstance in which people, the device, or the environment are exposed to a hazard.
These three components form the essential structure for understanding how risks occur, and ultimately, how they can be controlled.
A Simple Real-World Example: The Icy Pavement
To illustrate the definitions clearly, consider this example: a person walking on an icy pavement.
- Hazard: the icy pavement
- Hazardous situation: falling as a result of walking on the icy pavement
- Potential harms: vary in severity, such as slip but caught self and injured wrist, fall ans breaking a leg, severe injury or death due to the fall.
- Risk Controls: wearing appropriate shoes, gritting the pavement beforehand, or clearing the ice
This non-medical example helps visualise how hazards lead to hazardous situations, which can then lead to harm if not controlled.
Applying the Model to Medical Devices
In medical devices, these concepts follow the same structure:
- Identify the hazard
- Define the sequence of events leading to exposure
- Describe the hazardous situation
- Identify the potential harms
- Apply risk controls to break the chain
Thinking in this linear way (hazard → sequence of events → hazardous situation → harm → controls) makes it easier to populate your Risk Management File. This is especially useful when dealing with complex user interactions, use environments, or multi-step device operations.
Sometimes manufacturers find it easier to start by identifying the harm or hazardous situation, then work backwards to the hazard. This is also valid particularly during use-error analysis or usability engineering so long as the full chain is mapped clearly.
The Role of ISO 14971 and ISO/TR 24971
ISO 14971 and the accompanying guidance in ISO/TR 24971 support structured thinking.
ISO/TR 24971 contains question prompts and examples that help teams identify hazards across:
- Device characteristics
- Materials and biocompatibility
- Energy sources
- Software and cybersecurity
- User interactions
- Use environments
- Service and maintenance conditions
Using these standards consistently ensures your risk assessments remain aligned with international expectations and Notified Body review criteria.
Common Challenges Manufacturers Face
a) Mixing up hazard and hazardous situation
Many teams incorrectly document hazardous situations as hazards.
ISO 14971 requires clear differentiation.
b) Missing sequence of events
Without a defined sequence, risk pathways appear incomplete and controls cannot be appropriately placed.
c) Focusing only on user error
Human factors matter, but many risks originate from design choices or foreseeable misuse – not simply user mistakes.
d) Treating risk management as a one-time document
Not updating the risk file during change control or post-market phases is a frequent audit finding.
Practical Tips for Strengthening Your Risk Management Documentation
- Start with the definitions and ensure your team uses them consistently.
- Map hazards linearly—hazard → events → hazardous situation → harm—to improve clarity.
- Prioritise design-based risk controls before relying on labelling or training.
- Integrate usability engineering early to identify how users contribute to hazardous situations.
- Update your risk file continuously, especially when PMS, complaints, or CAPA activities reveal new information.
- Use ISO/TR 24971 guidance questions to identify hazards you may have missed.
LFH supports medical device manufacturers in building strong, compliant risk management systems aligned with ISO 14971 and MDR expectations. From hazard analysis and FMEA development to full lifecycle risk-management planning, our consultants help you create clear, defensible documentation ready for audit or Notified Body review.
FAQs – Hazard and Harm in Medical Device Risk Management
What is the difference between a hazard and harm?
A hazard is the source of potential harm, while harm is the actual injury or damage that could occur.
Does every hazard result in a hazardous situation?
No. A hazardous situation only exists when the user or environment enters a state of exposure.
Why are sequence-of-events important?
They show how a hazard leads to harm, allowing risk controls to be placed at the most effective point.
Is risk management only needed during design?
No. It is a lifecycle requirement, extending from design through post-market monitoring.
