A hazard can cause harm, but its consequences depend on who or what is exposed and how vulnerable they are.
A hazard is a potential source of harm. The harm it causes depends on who or what is exposed to it, and how vulnerable they are. Exposure means being within the hazard's reach. Vulnerability means being more likely to suffer harm, for example because leaving a building is difficult.
Faulty electrical appliances, damaged wiring or unattended cooking can start fires. Flames cause burns and damage homes; smoke can harm breathing. Items blocking an escape route make it harder for residents to leave, increasing the possible harm.
Air pollution can come from vegetation burning, industry and vehicles. Breathing harmful pollutants can cause respiratory illness and cardiovascular disease, which affects the heart and blood vessels. Long-term exposure to some pollutants increases lung-cancer risk. Pollution may come from nearby or distant sources, and may be invisible. A photograph cannot measure its concentration.
Traffic hazards include speeding, ignoring red lights and drink driving. These actions can make collisions more likely or more severe. Pedestrians, cyclists and vehicle occupants may be injured or killed. A busy road alone does not prove what caused a particular collision; the explanation needs evidence about behaviour and road conditions.
Step by step
Cause
Identify a specific process or behaviour that generates the hazard.
Exposure and vulnerability
Identify who encounters it and conditions that increase potential harm.
Consequence
Explain a health, property or service impact using that chain.
Worked example: Why speeding makes a crossing dangerous
Imagine a speeding vehicle approaching a crossing sooner than pedestrians expect. The driver has less time to stop, increasing collision risk. Older pedestrians who take longer to cross may spend more time in its path. This connects the driver's behaviour to exposure and possible harm.
Watch out for this
A hazard and a disaster are the same thing.
A hazard is a potential source of harm. A disaster involves serious disruption when a hazardous event affects exposed and vulnerable people or systems.
Check your understanding
Which statement gives a complete neighbourhood hazard chain?
- Unattended cooking starts a fire, and smoke entering nearby homes harms residents.
- A neighbourhood has buildings, so it must already be a disaster.
- A road is long, so every collision is caused by its length.