What is the difference between a hazard and a risk?

Quick answer: A hazard is anything that has the potential to cause harm — think wet floors, exposed wiring, or heavy machinery. A risk is the likelihood that a hazard will actually cause harm, and how serious that harm could be. Put simply, a hazard is the ‘what’, and risk is the ‘what if’.

In Health & Safety, these two terms often get used interchangeably, but they mean very different things. Understanding the distinction is essential for keeping your workplace safe, meeting your legal obligations, and protecting your people.

What is a hazard?

A hazard is anything that has the potential to cause harm. That could be a physical object, a substance, an environment, a process, or even a behaviour. Hazards exist in every workplace, from a bustling construction site to a quiet office. Recognising them is the first step towards managing them.

Acute vs chronic hazards

Not all hazards cause harm in the same way or at the same speed. It’s helpful to understand the difference between two key types:

• Acute hazards cause immediate harm — for example, a chemical splash that results in a burn, or a falling object that causes injury on impact.
• Chronic hazards cause harm gradually over time. These are often less obvious but can be just as serious. Examples include repeated exposure to loud noise (which can lead to hearing loss), prolonged inhalation of dust particles, or long-term stress from an unsafe working environment.

Chronic hazards are particularly easy to overlook because the damage isn’t immediately visible, which is exactly why regular risk assessments are so important.

The 5 common types of workplace hazard

Workplace hazards come in many shapes and sizes. Here are the five main categories to be aware of:

• Physical hazards — these are the most visible dangers, like wet floors, falling objects, poor lighting, or exposed wiring. A slippery step in a stairwell might seem minor, but it can cause a serious injury.
• Chemical hazards — from industrial cleaning agents to pesticides, any substance that can harm health if mishandled falls into this category. Proper storage, labelling, and training are essential.
• Biological hazards — particularly common in healthcare, food production, and labs. Exposure to bacteria, viruses, or mould can lead to illness if the right precautions aren’t in place.
• Ergonomic hazards — poorly designed workstations, repetitive tasks, and awkward postures can cause long-term musculoskeletal problems. Office workers and warehouse staff alike are at risk.
• Psychosocial hazards — stress, bullying, harassment, and burnout are just as real as physical dangers. A toxic workplace culture or unsustainable workload can take a serious toll on mental health.

What is a risk?

While a hazard is something that could cause harm, a risk is the chance that it actually will — combined with how serious the consequences could be. Risks aren’t fixed, they shift depending on who’s exposed, how often, and what controls are in place.

The most widely used formula for calculating risk level is:

Likelihood × Severity = Risk Level

This straightforward calculation helps businesses prioritise which hazards need the most urgent attention.

The wet floor example

Let’s bring this to life with a simple example. Say there’s a wet floor in your workplace – that’s the hazard. Now, the risk depends on the context:

• Wet floor in a busy reception area with no warning signs: Likelihood = High (3), Severity = High (3), Risk Level = 9 (Critical — immediate action required)
• Wet floor in a rarely used storage room with a sign in place: Likelihood = Low (1), Severity = Medium (2), Risk Level = 2 (Low — monitor and review)
• Wet floor on a stairwell: Likelihood = Medium (2), Severity = High (3), Risk Level = 6 (High — act quickly)

Same hazard, very different risk levels. That’s why context matters so much in risk assessment.

What’s the difference between a hazard and a risk?

Here’s a quick comparison to help make the distinction crystal clear:

Aspect	Hazard	Risk
Definition	Anything with the potential to cause harm	The likelihood of harm occurring, combined with its severity
Nature	Static — it exists until it’s removed or controlled	Dynamic — it changes based on context, controls, and exposure
Examples	Wet floor, exposed wiring, hazardous chemicals	Probability of slipping, likelihood of electric shock
Think of it as…	The ‘what’	The ‘what if’

How to assess risk

Once you’ve identified a hazard, the next step is assessing the risk it poses. A structured approach means you can prioritise effectively and apply proportionate controls, rather than treating every hazard the same regardless of how serious it is.

Using a risk matrix

A risk matrix is a straightforward visual tool that helps you evaluate and categorise risks. It plots likelihood against severity to give you a risk score, and a colour-coded sense of urgency.

Score interpretation:

• 1–2: Low risk — manage through routine procedures
• 3–4: Medium risk — review and implement additional controls
• 6: High risk — act quickly with targeted control measures
• 9: Critical risk — immediate action required

The risk matrix has its roots in military and engineering risk management, and has since become a standard tool promoted by organisations like the Health and Safety Executive (HSE) and OSHA. It’s useful across virtually every industry.

How to identify hazards in the workplace

Before you can assess risk, you need to find the hazards. Here are the most effective steps:

1. Conduct regular workplace inspections — walk your workspace with fresh eyes. Look for anything that could cause harm if left unaddressed, including cluttered walkways, exposed wiring, and poor ventilation.
2. Engage your employees — your team is often the first to notice hazards in their daily tasks. Create a simple, accessible system for reporting concerns.
3. Review incident and near-miss reports — past accidents are valuable data. Analysing them helps you spot patterns and prevent repeat incidents.
4. Monitor how tasks are performed — sometimes hazards only appear when you watch work in action: improper lifting, uncomfortable postures, or exposure to noise.
5. Consult industry-specific safety guidance — different sectors face different risks, and there’s usually sector-specific guidance from the HSE or relevant trade bodies to help.

Controlling hazards and risks: The hierarchy of controls

Identifying hazards and assessing risks is only useful if you do something about them. The Hierarchy of Controls is the gold-standard framework for managing workplace hazards, and it’s ranked from most effective to least effective.

• Elimination — remove the hazard entirely. It’s the most effective control. For example, replacing a hazardous chemical with a safer alternative.
• Substitution — if you can’t eliminate it, swap it for something less dangerous. Replacing a slippery floor cleaner with a non-slip formula is a great example.
• Engineering controls — use physical changes to reduce exposure, like installing machine guards, adding ventilation, or redesigning a workstation.
• Administrative controls — policies, procedures, and training that reduce how often people encounter a hazard. Job rotation to minimise repetitive strain is a classic example.
• Personal Protective Equipment (PPE) — the last line of defence. Gloves, helmets, high-visibility clothing, and other PPE protect individuals when other controls aren’t enough.

Remember: PPE should never be your first or only response to a hazard. Work through the hierarchy from the top down wherever possible.

Legal requirements around hazards and risks

UK law is clear; employers have a duty to protect their people. Here are the key pieces of legislation to know:

• Health and Safety at Work Act 1974 — the cornerstone of UK workplace safety law. Requires employers to protect employees and members of the public from workplace risks, as far as reasonably practicable.
• Management of Health and Safety at Work Regulations 1999 — mandates that employers carry out suitable and sufficient risk assessments and implement appropriate controls.
• Reporting of Injuries, Diseases and Dangerous Occurrences Regulations (RIDDOR) — requires employers to report and record certain workplace accidents, incidents, and ill-health cases.

Failure to comply can result in fines, legal action, and lasting reputational damage. Beyond legal compliance, though, good risk management simply makes for a better, safer, and more productive workplace.

What workplace hazards and risks can we expect in the future?

Workplaces never stand still, and neither do the hazards within them. Here are three emerging areas that businesses should keep on their radar:

• AI and automation — as collaborative robots (cobots) become more common, new safety risks are emerging. Without proper safeguards and protocols, working alongside automated machinery can introduce injury risks that simply didn’t exist before.
• Climate change — extreme heat, flooding, and unpredictable weather patterns are creating new hazards, particularly for outdoor workers in construction, agriculture, and utilities.
• Remote and hybrid working — the shift away from traditional offices has introduced ergonomic challenges and mental health pressures that many businesses are still getting to grips with. Home office setups often lack proper ergonomic support, and isolation can contribute to stress and burnout.

Staying ahead of these trends means regularly reviewing your risk assessments, keeping training up to date, and fostering a culture where people feel comfortable raising concerns.

Frequently asked questions

What is the difference between a hazard and a risk?

A hazard is anything with the potential to cause harm — a wet floor, a chemical, or a faulty piece of equipment. A risk is the likelihood that the hazard will cause harm, and how serious that harm could be. Hazards are the ‘what’; risk is the ‘what if’.

How do you calculate risk level?

The most widely used formula is: Likelihood × Severity = Risk Level. Using a risk matrix, you can score each factor (typically on a scale of 1–3) and plot the result to determine whether the risk is low, medium, high, or critical. This helps you prioritise which hazards need the most urgent attention.

What are the 5 types of hazards?

The five main categories of workplace hazard are: physical, chemical, biological, ergonomic, and psychosocial. Each requires a different approach to identification and control, but all need to be considered as part of a thorough risk assessment.

What is the Hierarchy of Controls?

The Hierarchy of Controls is a five-level framework for managing workplace hazards. From most to least effective: Elimination, Substitution, Engineering Controls, Administrative Controls, and PPE. It’s designed to guide you towards the most effective solution first, rather than defaulting to PPE as a quick fix.

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