What is a hazard? Meaning, types and how to identify hazards at work

A hazard is anything that could cause injury or illness at work, such as a chemical, a machine, electricity, a heavy load or working from a ladder. The risk is how likely it is that someone could be harmed by that hazard, and how seriously. That is how HSE frames the two words in its risk assessment guidance. The difference matters because the law asks you to manage the risk. In Great Britain, regulation 3 of the Management of Health and Safety at Work Regulations 1999 requires every employer to make a suitable and sufficient assessment of the risks to employees and to anyone else affected by the work.

What is the definition of a hazard?

HSE's current guidance describes the first step of managing risk as identifying "what could cause injury or illness in your business (hazards)". Its agriculture guidance gives the shortest version: "A 'hazard' is anything that might cause harm, such as working from ladders or electricity."

The general duties in section 2 of the Health and Safety at Work etc. Act 1974 and the risk assessment duty in regulation 3 of the 1999 Regulations talk about risks, and leave the word hazard to guidance. Where regulations do define the word, each defines it for its own subject. For substances hazardous to health, regulation 2 of the Control of Substances Hazardous to Health Regulations 2002 defines a hazard as "the intrinsic property of that substance which has the potential to cause harm to the health of a person". Regulation 2 of the Dangerous Substances and Explosive Atmospheres Regulations 2002 has its own definition, for dangerous substances.

Outside work, the word turns up in the hazard perception part of the driving test and in talk of natural hazards such as flooding. This guide sticks to the workplace.

What is the difference between a hazard and a risk?

The hazard is the thing that could cause harm. The risk is the chance that it does, combined with how bad the harm would be. HSE's guidance puts both parts in one step: decide "how likely it is that someone could be harmed and how seriously (the risk)".

A hazard stays a hazard until it is removed. Controls reduce the risk: a guard leaves a machine's blade as sharp as ever, and what it changes is how likely anyone is to touch it. That is why HSE's first question is whether you can get rid of the hazard altogether, and only then how to control the risk.

Hazard	The risk	A control that reduces it
Spilled liquid on a walkway	Someone slips, falls and is injured	Clear spills straight away and fix whatever is leaking
A cleaning chemical	Skin or breathing problems for the person using it	A less harmful product, then ventilation and gloves
A lift truck working in a yard	A pedestrian is struck	Separate walkways from vehicle routes
A damaged extension lead	Electric shock or burns	Inspect and maintain equipment, and take damaged leads out of use
A ladder	A fall from height	Avoid the work at height, or use a safer working platform

The law does not expect a world without risk. HSE's guidance is: "You're not expected to eliminate all risks but you need to do everything 'reasonably practicable' to protect people from harm."

Types of hazard at work, with examples

One way to group hazards is by what causes the harm: substances, physical energy such as noise or electricity, the work itself, and the way work is organised. In Great Britain most of the types below have their own regulations, and some, such as COSHH and the noise, vibration and manual handling regulations, set out what the risk assessment for that hazard has to cover.

Chemical and dust hazards

HSE's examples of harmful substances run "from paints and cleaners to flour dust, solder fume, blood or waste", and processes create their own: wood dust from sanding, silica dust from cutting tiles, fume from welding. The Control of Substances Hazardous to Health Regulations 2002 apply, and our guide to what COSHH covers explains the duties. Where a substance can burn or explode, as solvents, paints and flour or wood dust can, that fire and explosion risk falls under DSEAR.

Biological hazards

These are bacteria, viruses and other micro-organisms that can cause infection, allergy or toxicity. HSE's examples of where people meet them at work include blood, body fluids, contaminated water and waste. Biological agents are also covered by COSHH. Legionella bacteria in water systems are one example, and they are what a legionella risk assessment is for.

Noise and vibration

Noise damages hearing over time, and HSE's point is a blunt one: "once your hearing has gone it won't come back." The Control of Noise at Work Regulations 2005 require an assessment where work is liable to expose employees at or above a lower exposure action value. Vibration from power tools can cause hand-arm vibration syndrome, which HSE describes as "a painful and disabling condition", and is covered by the Control of Vibration at Work Regulations 2005.

Electrical hazards

HSE lists the main hazards of working with electricity as electric shock and burns from contact with live parts, injury from arcing, fire from faulty equipment or installations, explosion caused by unsuitable electrical apparatus, and static electricity igniting flammable vapours or dusts. A shock can also cause a second injury, such as a fall from a ladder. In wet surroundings, HSE warns, "unsuitable equipment can become live and make its surroundings live too." The Electricity at Work Regulations 1989 require electrical systems to be built and maintained so as to prevent danger, so far as is reasonably practicable.

Work at height

Any place where, if no precautions were taken, a person could fall a distance liable to cause personal injury, including a place at or below ground level such as a pit or an open excavation. Falls from ladders and through fragile surfaces are HSE's common cases. The Work at Height Regulations 2005 require you to avoid work at height where it is reasonably practicable to do the work safely another way.

Manual handling

Lifting, carrying, pushing, pulling or supporting a load by hand or bodily force, where, in HSE's words, the load can be "an object, person or animal". HSE notes that the weight of a load matters, "though the law does not set specific weight limits". The Manual Handling Operations Regulations 1992 apply, and our manual handling guide walks through the assessment they require.

Work equipment and machinery

This covers dangerous moving parts, rotating shafts, blades and anything else on the equipment people use at work. The Provision and Use of Work Equipment Regulations 1998 require equipment suitable for its use and measures to stop people reaching dangerous parts. Our guide to PUWER and machinery guarding covers the order those measures come in.

Workplace transport

Lift trucks, HGVs, vans and plant moving where people walk. HSE describes people being "knocked down, run over, or crushed against fixed parts by vehicles", and falls from vehicles during loading and unloading. Regulation 17 of the Workplace (Health, Safety and Welfare) Regulations 1992 requires a workplace organised so that pedestrians and vehicles can circulate safely, and HSE's guidance calls separating them "the most effective way of protecting them". Our builders merchant hazards guide works through a yard where this matters every day.

Display screen equipment

Incorrect use of screens or a poorly designed workstation can lead, in HSE's words, to "pain in necks, shoulders, backs, arms, wrists and hands as well as fatigue and eye strain". The Health and Safety (Display Screen Equipment) Regulations 1992 cover employees who habitually use screens as a significant part of their normal work. If your team works at screens, our guide to DSE assessments covers what the duty involves.

Fire

A fire needs three things: a source of ignition, a source of fuel and oxygen. The fire risk assessment duty sits in the fire legislation: the Regulatory Reform (Fire Safety) Order 2005 in England and Wales, with separate fire safety legislation in Scotland and Northern Ireland. Our fire risk assessments page sets out what one covers.

Work-related stress

HSE defines stress as "the adverse reaction people have to excessive pressures or other types of demand placed on them". The duty is the general risk assessment, and HSE's view is that "Employers have a legal duty to protect workers from stress at work by doing a risk assessment and acting on it." Its Management Standards cover six areas of work design: demands, control, support, relationships, role and change.

How to identify hazards in your workplace

HSE's guidance on spotting hazards comes down to a few habits:

1. Walk around the workplace and watch how people work. The way a job is actually done can differ from the way it is written down.
2. Ask the people doing the work. In HSE's words, "They may have spotted something you have not noticed."
3. Read the manufacturers' instructions and safety data sheets, which name the hazards of equipment and chemicals. Some harmful substances are made by the process itself, such as dust from cutting.
4. Look at your accident and ill-health records, which HSE says "can help you identify less obvious hazards".
5. Include the work done only now and then, such as maintenance, cleaning and changes in production. HSE calls these non-routine operations.
6. Think about long-term health hazards such as noise, dust and manual handling, as well as the obvious safety hazards.
7. For each hazard, think about who could be harmed and how: employees, contractors, visitors and members of the public, and people with particular needs, such as young workers, new or expectant mothers and people with disabilities.

If you employ five or more people, regulation 3(6) of the 1999 Regulations requires you to record the significant findings of the assessment and any group of employees it identifies as especially at risk. The assessment must be reviewed if there is reason to suspect it is no longer valid or there has been a significant change, and HSE suggests a review after accidents, near misses or problems your workers have spotted. Our risk assessment training is for the managers and supervisors who do this, and our guide to what health and safety requires of an employer covers the wider duties.

What to do once you have found a hazard

Get rid of it if you can. If you cannot, control the risk. HSE's guidance on personal protective equipment sets out the order to work through, "with elimination being the most effective and PPE being the least effective":

Level	What it means	Example
Elimination	Physically remove the hazard	Do the work at ground level instead of on a ladder
Substitution	Replace the hazard with something less dangerous	A less harmful cleaning product
Engineering controls	Isolate people from the hazard	A fixed guard, extraction at the point dust is made, or a walkway physically separated from vehicles
Administrative controls	Change the way people work	Safe systems of work, permits to work, training
Personal protective equipment	Protect the worker with equipment	Gloves, hearing protection, respiratory protective equipment

Some regulations write their own order into law. Regulation 7 of COSHH 2002, for example, prefers substitution and puts personal protective equipment last, and PUWER sets an order for guarding. HSE's COSHH guidance also warns against reading the order so rigidly that some options look automatically good and others bad. The aim is the most reliable controls for the hazard in front of you, and in many cases that means a mix of them.

Which hazards cause the most harm?

HSE publishes which kinds of accident cause the most injuries. According to HSE's injury statistics, in Great Britain in 2024/25, the main kinds of accident behind non-fatal injuries to employees reported under RIDDOR were slips, trips or falls on the same level (30%), handling, lifting or carrying (17%), being struck by a moving object (10%), acts of violence (10%) and falls from height (8%). HSE estimates that employers report only around half of these injuries.

Fatal accidents follow a different pattern. HSE's provisional figures for 2025/26 put falls from height first, with 31 deaths, then being struck by a moving vehicle (24) and by a moving object (21). Then there is ill health. For 2024/25, HSE estimates 964,000 workers suffering work-related stress, depression or anxiety, and 511,000 with a work-related musculoskeletal disorder.

Frequently asked questions

What is a hazard? Anything that could cause injury or illness at work, such as a chemical, a machine, electricity, a heavy load or working at height.

What is the difference between a hazard and a risk? A hazard is the thing that could cause harm; the risk is how likely it is that someone is harmed by it, and how seriously. A wet floor is a hazard; the risk is the chance that someone slips on it and how badly they are hurt.

What are some examples of hazards in the workplace? Chemicals and dust, biological agents such as bacteria in water systems, noise, vibration, electricity, work at height, manual handling, moving machinery, vehicles, display screen work, fire and work-related stress.

What are electrical hazards? HSE lists electric shock and burns from live parts, injury from arcing, fire from faulty equipment, explosion caused by unsuitable apparatus, and static electricity igniting flammable vapours or dusts. In Great Britain, the Electricity at Work Regulations 1989 require systems to be built and maintained to prevent danger, so far as is reasonably practicable.

What is hazard identification? The first step of a risk assessment: finding what could cause injury or illness in your workplace, by walking round, asking the people who do the work, reading instructions and safety data sheets, and checking your accident records.

Do I have to record the hazards I find? If you employ five or more people, yes: regulation 3 of the Management of Health and Safety at Work Regulations 1999 requires you to record the significant findings of your risk assessment. Below five, the general risk assessment does not have to be in writing. Noise and vibration assessments, and in England and Wales the fire risk assessment, must be recorded whatever your size.

Is work-related stress a workplace hazard? Yes. HSE says employers have a legal duty to protect workers from stress at work by assessing the risk and acting on it, and its Management Standards cover the six areas of work design linked to it: demands, control, support, relationships, role and change.