What Are Hazardous Substances: Your 2026 UK Guide

You're probably surrounded by hazardous substances already and not calling them that.

A spray bottle under the sink in your office kitchen. Dust from a small refit in the stockroom. Floor coating used in a gym studio. Printer toner, descaler, disinfectant, solvent wipes, pest control products. Most managers don't miss these items because they're careless. They miss them because they don't look like “chemical hazards” in the dramatic sense.

That's where compliance starts to drift. People assume hazardous substances only belong in factories or labs, and they assume gloves or a basic mask solve the problem. In UK workplaces, that approach is risky. The law focuses on health harm from exposure, not on whether the substance looks dangerous or whether you only use a small amount.

If you manage staff, premises, or contractors, you need a practical answer to a simple question: what are hazardous substances in your workplace, and what are you expected to do about them? The short answer is wider than most employers expect. It also matters in offices, gyms, hospitality venues, retail units, events spaces, and light commercial environments just as much as in manufacturing.

For a broader view of your employer duties, occupational health and safety responsibilities are the right place to start before you drill into substance-specific controls.

Table of Contents

• An Introduction to Hazardous Substances in Your Workplace - What makes this difficult for employers - What employers need to do

• Defining Hazardous Substances Under UK Law - What counts as a hazardous substance - How to identify hazardous substances properly - Workplace Exposure Limits and what they mean

• Common Hazardous Substances by Workplace Sector - Where managers usually overlook exposure - Examples of hazardous substances in UK workplaces

• The Health Risks of Workplace Exposure - How exposure happens - Immediate harm and long-term damage

• Your Legal Duty A Guide to COSHH Risk Assessments - What a COSHH assessment should actually do - A workable assessment process

• Implementing the Hierarchy of Controls Effectively - Why PPE fails as a primary control - Apply the hierarchy in the right order - What this looks like in non-industrial workplaces

• Training Recordkeeping and Emergency Preparedness - Train people for the task not the policy file - Keep evidence and prepare for things going wrong

An Introduction to Hazardous Substances in Your Workplace

A hazardous substance is any substance that can harm health if someone breathes it in, gets it on their skin, swallows it, or is otherwise exposed to it during work. That includes obvious chemical products, but it also includes dusts, fumes, vapours and biological agents that appear during normal tasks.

In practice, the problem usually starts with routine work. Your cleaners decant products into smaller bottles. A contractor cuts materials during a shop fit-out. Staff use strong disinfectants in treatment rooms, washrooms or gyms. None of that feels like heavy industry, but exposure still happens.

What makes this difficult for employers

The biggest mistake I see is treating hazardous substances as a purchasing issue instead of an exposure issue. Managers check whether a product is “approved” or commonly used, then stop there. The actual question is different. How can this substance reach people, and what control stops that from happening?

A second mistake is assuming quantity decides whether COSHH applies. It doesn't work like that in day-to-day compliance. Small amounts can still create harmful vapour, mist, residue or dust, especially in enclosed spaces or during cleaning, maintenance and refurbishment.

Practical rule: If a substance can harm health in the way you use it, store it, mix it, spray it, cut it, heat it or clean it up, treat it as a COSHH question until you've checked properly.

What employers need to do

Your duty is not just to hand over PPE and hope staff use it correctly. You need to identify hazardous substances, assess the risk, decide on suitable controls, make sure those controls work, and keep the arrangement under review.

That means looking beyond storerooms and chemical cupboards. It includes process-generated hazards, contractor activities, waste handling, poor ventilation, and contamination left behind after work is finished. A tidy premises can still have serious exposure routes.

For most organisations, the starting point is simple:

• List substances and tasks: Include bought-in products and hazards created by the work itself.

• Check how people are exposed: Breathing in dust and vapour is often the issue, but skin contact matters too.

• Challenge assumptions: “We only use a little” and “staff wear gloves” are not enough on their own.

Defining Hazardous Substances Under UK Law

A facilities manager in an office block approves a cleaner, a washroom descaler and a can of spray adhesive for a minor repair. None of it feels like "chemical work". Staff have gloves in the cupboard, so the risk looks covered. Under UK law, that is the wrong starting point.

COSHH applies wherever substances hazardous to health are present or created by work. That includes offices, gyms, shops and other premises that do not see themselves as high risk. It also applies when you only use small amounts. If the substance can harm health through breathing it in, getting it on the skin, swallowing residue by accident, or through contact with the eyes, you need to assess the risk and control exposure.

What counts as a hazardous substance

The legal definition is wider than many managers expect. It covers not only products with hazard symbols, but also substances generated by the task itself and biological agents in certain settings.

In practice, hazardous substances usually fall into three groups:

• Bought-in products: Cleaning chemicals, sanitisers, adhesives, paints, toners, descalers, solvents and maintenance products.

• Substances produced by work: Dust from drilling or sanding, fumes from heating materials, vapours from coatings, mists from spraying, and residues left on surfaces.

• Biological agents: Bacteria, moulds and other contamination risks linked to waste, damp conditions, cleaning work, leisure settings or care-related tasks.

This catches employers out because they look for containers, not exposure. A retail refit can create respirable dust. A gym floor treatment can release vapour. A small office can trap cleaning spray in a poorly ventilated store room.

How to identify hazardous substances properly

Start with the label and the safety data sheet. They tell you the hazard classification, handling precautions, first aid measures, storage requirements and incompatible materials. They do not assess your job for you.

The purpose of a COSHH assessment is to examine how the substance is used in your workplace, by your staff, with your layout, ventilation and work routine. That is why PPE on its own is rarely a sound first answer. Gloves and masks depend on correct selection, fit, use, maintenance and supervision. If you can eliminate the product, substitute it, reduce mist or vapour, or improve local ventilation, those controls are more reliable.

A simple example proves the point. The same disinfectant can present a low risk when used in small wipes on open surfaces, and a much higher risk when decanted into a spray bottle and used repeatedly in a back room with poor airflow.

You also need to look for hazards that never arrive with a supplier label. Dust from contractors, fumes from hot works, aerosol from spraying, and mist from some cleaning methods all fall within COSHH if they can damage health. Employers in production settings often miss this too during maintenance and changeovers, even where they already have broader health and safety arrangements in manufacturing.

Workplace Exposure Limits and what they mean

Some substances have a Workplace Exposure Limit, or WEL. A WEL is a legal benchmark for the concentration of a substance in workplace air over a set period. It helps you judge whether exposure is being controlled to an acceptable standard.

Treat that benchmark carefully. A WEL is not a target to work up to. If exposure can be reduced further by a safer process, better extraction, closed transfer, or a different application method, that is the better course. The legal test is control of exposure, not issuing PPE and assuming the problem is solved.

Common Hazardous Substances by Workplace Sector

The easiest way to miss a hazardous substance is to assume your sector is too ordinary for COSHH problems. That's why low-risk premises often end up with basic but stubborn compliance gaps.

Recent UK enforcement trends show a 15% increase in HSE inspections in ‘low-risk' sectors for hidden hazards such as silica dust in small fit-out projects and isocyanates in gym floor coatings, as noted in this University of Nottingham hazardous substances document. That matters because many owners still assume small amounts don't trigger assessment duties.

Where managers usually overlook exposure

In offices, managers often focus on stationery and electrical safety while ignoring cleaning chemicals, washroom products and contractor dust. In gyms, the hazard may come from disinfectants, pool-related chemicals, floor coatings or damp environments. In retail, the risk often appears during refits, seasonal display changes and cleaning tasks outside trading hours.

Manufacturing sites usually expect chemical risks, but even there the weak point is often routine handling, not exotic substances. People get comfortable with degreasers, oils, metalworking fluids, solvent wipes and process fumes because they're used every day.

Examples of hazardous substances in UK workplaces

Sector	Common hazardous substances	Example source of exposure
Construction	Silica dust, cement, coatings	Cutting materials, mixing products, cleanup after works
Manufacturing	Solvents, metal fumes, process dusts	Welding, spraying, degreasing, machining
Hospitality	Cleaning agents, oven cleaners, descalers	Kitchen deep cleans, decanting chemicals, poor ventilation
Retail	Refit dust, adhesives, paints, cleaning sprays	Shopfitting, display installation, after-hours cleaning
Gyms and fitness	Disinfectants, floor coatings, pool chemicals, biological contamination	Surface cleaning, flooring works, plant room tasks, humid areas

One manufacturing-focused example worth reviewing is health and safety in manufacturing, because it shows how normal production tasks create exposure even when nobody is handling a substance that looks especially dramatic.

Small quantity doesn't mean small risk. A brief task in a poorly ventilated room can matter more than a larger task with proper controls.

The practical lesson is straightforward. Don't build your substance register around what you buy alone. Build it around what people breathe in, touch, mix, disturb, spray, heat, remove and clean up.

The Health Risks of Workplace Exposure

A cleaner sprays disinfectant across a changing room daily. A retail supervisor wipes adhesive residue from shelving in a stockroom with the door shut. An office caretaker tops up a toilet cleaner from a larger container. None of those tasks look high risk at first glance. Each can still expose staff to substances that irritate the lungs, damage skin, trigger asthma, or cause harm over time if you rely on gloves and masks instead of controlling the task properly.

The level of harm depends on four practical factors. What the substance is, how it enters the body, how long the exposure lasts, and what controls are working on the day. The setting does not change that. Offices, gyms, shops, kitchens, workshops and warehouses all create exposure if substances are sprayed, mixed, heated, decanted, disturbed or cleaned up without proper control.

How exposure happens

For day-to-day management, focus on the routes people are exposed rather than the label on the container alone.

• Inhalation: Dust, vapour, mist, fume and aerosol are often the main concern. People can breathe in harmful substances without realising it, especially where ventilation is poor or the task is short and repeated.

• Skin contact: Wet work, splashes, contaminated gloves, chemical residues on handles and repeated handling can cause irritation, burns and occupational dermatitis.

• Ingestion: This usually happens through poor hygiene. Contamination transfers from hands, gloves or surfaces to food, drink, cigarettes or the mouth.

Inhalation is regularly missed in non-industrial workplaces because the hazard is not always visible. A product can smell mild and still create a problem. Dust and spray residues can also settle, then become airborne again during cleaning, restocking or the next shift.

Immediate harm and long-term damage

Some effects show up quickly. Staff may develop headaches, dizziness, coughing, sore eyes, nausea, skin irritation or chemical burns. Those cases usually get reported because the link between the task and the harm is obvious.

The harder problem to manage is repeated low-level exposure. That is how businesses end up with dermatitis from routine cleaning, asthma triggered by sprays or fumes, and sensitisation that means a worker reacts to very small amounts after repeated contact. Once someone becomes sensitised, keeping them safe becomes much harder and job changes may be needed.

This is also where I see a common mistake. PPE gets treated as the control measure, rather than the back-up measure. Gloves, masks and eye protection have their place, but they depend on correct selection, fit, maintenance, storage, training and consistent use. If your system only works when every person wears PPE correctly every time, your exposure control is weak.

Small amounts do not remove the risk. A brief task with a concentrated cleaner in a poorly ventilated office toilet can matter more than a longer task with extraction and safer application methods. The same applies in gyms using disinfectants, retail units during refits, and back-of-house areas where staff decant products into spray bottles.

A sensible way to judge the wider risk is to start with the task, then assess who is exposed, how often it happens, and what would happen if the controls failed. If your managers need a broader framework before building the COSHH detail, use this guide on how to conduct a workplace risk assessment.

Under COSHH, the concern is not limited to dramatic spills or obvious industrial chemicals. The actual health risk often comes from ordinary products used in ordinary places, with ordinary shortcuts.

Your Legal Duty A Guide to COSHH Risk Assessments

A COSHH assessment should answer a practical question: what could harm people here, during this task, and what are you doing to stop that exposure? If your document can't answer that clearly, it won't help your supervisors and it won't help you if something goes wrong.

This is also where many businesses get stuck. They download a generic form, list a few products, mention gloves, then file it away. That is not a useful assessment.

What a COSHH assessment should actually do

A sound assessment connects four things. The substance, the task, the people exposed, and the control measures. It also needs to reflect the place where the work happens, because ventilation, occupancy, frequency and cleaning arrangements all change the risk.

If you need a broader assessment method, this guide on how to conduct risk assessment gives a useful foundation before you build the COSHH detail.

Later in the process, it helps to see the steps visually.

https://www.youtube.com/embed/DImwvHpvKis

A workable assessment process

Use a process your managers can repeat consistently.

1. Identify the hazardous substance Check products, safety data sheets, labels, contractor materials and process-generated hazards such as dust or fumes.

2. Look at the task, not just the substance Ask how it is used. Is it sprayed, heated, diluted, mixed, decanted, sanded, cut or cleaned up? A low-concern product can become higher risk if the task changes the exposure route.

3. Decide who might be harmed Include cleaners, maintenance staff, contractors, reception teams, instructors, warehouse staff and anyone passing through the area. Don't forget vulnerable groups or people working alone.

4. Evaluate the controls already in place Consider ventilation, enclosed systems, work methods, segregation, cleaning regimes and supervision. PPE belongs here, but not as your automatic first answer.

5. Record clear actions Good actions are specific. “Use extraction during cutting” is useful. “Take care” is not.

6. Review and update Revisit the assessment if the product changes, the task changes, complaints arise, staff report symptoms, or contractors introduce new materials.

Under COSHH, assessments must consider occupational exposure limits such as WELs. If exposure can't be eliminated, the employer must ensure compliance with the approved WEL for that substance, which acts as a benchmark for judging whether controls are effective, as described in the summary of COSHH exposure limit requirements.

A useful assessment is operational. Supervisors can act on it. Staff can follow it. You can review it without guessing what the original writer meant.

Implementing the Hierarchy of Controls Effectively

A retail manager keeps disinfectant spray behind the till, a gym supervisor stores cleaning chemicals in a cupboard by the studio, and an office manager buys drain cleaner for the kitchen sink. In each case, the first response is often the same. Hand out gloves, tell staff to be careful, and assume the risk is covered.

That is the mistake.

Under COSHH, PPE is not your main control measure. It sits at the bottom of the hierarchy and deals with what is left after you have removed, replaced, enclosed, extracted, or otherwise reduced exposure. This matters just as much in offices, shops, salons, gyms, and small hospitality sites as it does in workshops and factories. Small quantities do not remove your duty to assess the substance or control exposure properly.

Why PPE fails as a primary control

PPE relies on people doing several things right every time. You need the correct specification, the right fit, proper storage, timely replacement, and staff who wear it for the specific exposure involved. If one part fails, protection drops quickly.

In practice, that happens often.

Gloves are worn with the wrong chemical rating. Masks are bought without checking the task. Eye protection is available but not used during short jobs because the person thinks they will "only be a minute". None of that removes fumes from the room or dust from the air. It only tries to reduce the harm after the substance has already been released.

The stronger controls change the task or the environment so that exposure is lower before a person reaches for PPE.

Apply the hierarchy in the right order

Use the hierarchy as a decision process, not a poster on the wall.

• Elimination: Remove the substance or stop doing the task in that form. If you can buy pre-diluted product instead of decanting concentrate, you remove a common exposure point.

• Substitution: Choose a less hazardous product or method. This is often possible with cleaning agents, adhesives, inks, solvents, and descalers.

• Engineering controls: Control the release at source. Use enclosure, local extraction, suitable general ventilation, closed containers, or dosing systems that avoid open pouring.

• Administrative controls: Limit who does the task, when it is done, how long it lasts, and how the area is managed. Clear work instructions and supervision sit here.

• PPE: Use it for the remaining risk, not as the whole plan.

The trade-off is straightforward. Higher-level controls usually take more thought, and sometimes more money up front, but they are more reliable. PPE is cheap to issue and easy to write into a procedure, yet it is the control most likely to fail in day-to-day use.

What this looks like in non-industrial workplaces

The hierarchy is not only for high-hazard plant rooms or manufacturing lines. I see the same control failures in lower-risk settings where managers assume the amount is too small to matter.

Situation	Weak control	Better control
Spray cleaner used in a small office washroom	Gloves and an open window	Switch to a less hazardous product, avoid fine spray application, improve ventilation, restrict use to trained staff
Solvent adhesive used during shop display changes	Disposable mask only	Substitute the adhesive where possible, isolate the work area, improve airflow, schedule work out of trading hours
Floor stripper used in a gym changing area	PPE issued to cleaners	Select a lower-risk product, control dilution, keep the area closed, ventilate properly before reopening
Drain cleaner used by facilities staff in a staff kitchen	Goggles and gloves only	Use a safer method first, avoid routine decanting, restrict access, provide clear instructions for storage and use

These are ordinary tasks. They still need a COSHH assessment.

If your assessment ends with "staff to wear gloves and mask", revisit it. Ask what you can remove, replace, contain, or ventilate first. That is the point where COSHH moves from paperwork to control.

Training Recordkeeping and Emergency Preparedness

Even a well-written COSHH assessment fails if staff don't understand what it means on the job. Training needs to be tied to the task people carry out, the products they use, the symptoms they should report, and the controls they must not bypass.

Train people for the task not the policy file

A toolbox talk that says “wear PPE and follow procedures” won't do much. People need practical instruction. Which product are they using? Where is the ventilation? What should never be mixed? What do they do if a spray nozzle blocks, a substance spills, or someone starts to feel unwell?

Focus training on the points where people make real decisions:

• Handling and use: Safe dilution, decanting, application and disposal.

• Recognition: Early signs of irritation, breathing problems, skin damage or poor control.

• Escalation: Who to tell, when to stop work, and how to isolate the area.

Keep evidence and prepare for things going wrong

Your records are your proof that the system exists beyond good intentions. Keep COSHH assessments, training records, inspection notes, maintenance records for control measures, and any health surveillance documents where relevant. If you source electrical or electronic equipment, documentation matters there too. In Great Britain, RoHS compliance requires a Technical Package, including a Declaration of Conformity and test reports, to be kept for 10 years after the last product is placed on the market, and it must be available to OPSS on request, as set out in the Great Britain RoHS regulations guidance.

Your emergency arrangements should be equally practical:

• Spills: Clear isolation, cleanup procedure, and access to the right materials.

• Exposure incidents: Immediate first aid steps, supervision, and reporting.

• Information access: Safety data sheets and emergency contacts available for staff to use.

Good hazardous substance management is repetitive by design. Train, check, record, review, and correct. That's how control stays real after the assessment is signed.

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If you need help turning COSHH duties into something workable across offices, gyms, retail sites, hospitality venues or higher-risk operations, KODOBI can support you with practical health and safety consultancy, gap analysis, training, audits and proportionate management systems that fit how your teams work.