COSHH Assessment: Complete Guide to Controlling Hazardous Substances

TL;DR: A COSHH assessment identifies the hazardous substances in your workplace, evaluates who is at risk, and documents the controls you have in place. If your business uses any chemicals — including everyday cleaning products, paints, adhesives, or anything that creates dust or fumes — you are legally required to carry one out. The process is straightforward: inventory your substances, gather Safety Data Sheets, assess the risks, put controls in place, and record everything. This guide walks you through it step by step.

If you have ever used bleach to clean a surface, mixed a bucket of adhesive, or sanded a piece of timber, you have worked with a hazardous substance. That might sound dramatic, but in the eyes of health and safety law, it is a simple fact.

The good news? Dealing with it is nowhere near as complicated as it sounds. A COSHH assessment is not a laboratory exercise. It is a practical, common-sense process that any business owner can work through — and this guide will show you exactly how.

What Is a COSHH Assessment?

COSHH stands for Control of Substances Hazardous to Health. It is a set of regulations that require employers (and self-employed people) to assess and control the risks from hazardous substances used in the workplace.

A COSHH assessment is the formal document that records:

• What hazardous substances are present in your workplace
• Who might be exposed to them (and how)
• What controls you have in place to prevent harm
• What action you will take if something goes wrong

Think of it as a structured way of answering one question: “Are my people safe from the chemicals and substances they work with?”

It is not just about “dangerous chemicals”

This is the part that catches most people out. When you hear “hazardous substances,” you might picture skull-and-crossbones labels on industrial drums. But COSHH covers a much wider range of everyday items:

• Bleach and bathroom cleaners
• Paint and wood stain
• Dust from cutting, sanding, or sweeping
• Glue and adhesives
• Washing-up liquid in some workplace contexts
• Air fresheners and aerosol sprays

If a product has a hazard warning on the label — even a mild one — it falls under COSHH.

Do You Need a COSHH Assessment?

The short answer: if your business uses any hazardous substances, yes.

The legal position

In the United Kingdom, the relevant legislation is the Control of Substances Hazardous to Health Regulations 2002 (as amended). These regulations apply to all employers, self-employed individuals, and anyone who controls a workplace where hazardous substances are used.

In Ireland, the equivalent is the Chemical Agents Regulations 2001 (SI No. 619/2001), enforced by the Health and Safety Authority (HSA). The obligations are very similar — you must assess the risk, put controls in place, and keep records.

Who does this apply to?

In practical terms, this means virtually every business. If you use any of the following, you need a COSHH assessment:

• Cleaning products (bleach, degreasers, disinfectants, glass cleaners)
• Adhesives and sealants
• Paints, stains, and varnishes
• Solvents and thinners
• Anything that creates dust (wood, plaster, cement, flour)
• Anything that creates fumes (welding, soldering, cooking oils at high temperatures)
• Fuels and lubricants
• Pesticides and herbicides

What if I am a sole trader?

You still need one. Under both UK and Irish law, self-employed people have a duty to protect themselves and anyone else who might be affected by their work. If a client, visitor, or passer-by could be exposed to a substance you are using, you have a legal obligation to assess and control that risk.

Penalties for non-compliance

Failure to carry out COSHH assessments can result in enforcement notices, fines, and in serious cases, prosecution. In the UK, the Health and Safety Executive (HSE) can issue improvement notices or prohibition notices on the spot during an inspection. Fines for health and safety offences in Magistrates’ Courts can reach unlimited amounts, and Crown Court prosecutions can result in custodial sentences for the most serious breaches.

In Ireland, the HSA has similar enforcement powers, with on-the-spot fines and the ability to prosecute employers who fail to meet their obligations under the Chemical Agents Regulations.

The bottom line: this is not optional.

What Counts as a Hazardous Substance?

COSHH covers any substance that could cause harm to health. This breaks down into several categories:

Chemicals

This is the broadest category and includes:

• Cleaning products — bleach, degreasers, oven cleaners, disinfectants, window cleaners
• Solvents — white spirit, acetone, methylated spirits, thinners
• Adhesives — contact adhesive, epoxy resin, PVA in industrial quantities, superglue
• Paints and coatings — spray paints, wood stains, varnishes, primers
• Fuels — petrol, diesel, LPG

Dust

Dust is one of the most overlooked hazardous substances. It does not come in a bottle with a warning label, but it can cause serious long-term health problems:

• Wood dust — a known cause of nasal cancer and occupational asthma
• Silica dust — from cutting concrete, stone, or brick; causes silicosis
• Flour dust — a major cause of occupational asthma in bakeries
• Plaster and cement dust — irritant to lungs and skin

Fumes

• Welding fumes — contain metal particles and gases that damage the lungs
• Soldering fumes — flux fumes can cause occupational asthma
• Paint spray mist — fine droplets that are easily inhaled

Biological agents

• Bacteria — legionella in water systems, leptospirosis from contaminated water
• Viruses — relevant in healthcare and cleaning settings
• Fungi and moulds — particularly in damp environments or demolition work

How to check if something is hazardous

There are two simple ways to check:

1. Look at the label. If a product carries any of the CLP (Classification, Labelling and Packaging) hazard symbols — the red-bordered diamond shapes — it is classified as hazardous. Common symbols include the exclamation mark (irritant), the health hazard silhouette (serious health effects), the flame (flammable), and the corrosion symbol.

2. Check the Safety Data Sheet (SDS). Every chemical product supplier is legally required to provide an SDS. Section 2 of the SDS tells you exactly what the hazards are.

The “household products” misconception

One of the most common mistakes is thinking: “I only use household cleaning products, so I do not need a COSHH assessment.”

This is wrong. Household products like bleach, oven cleaner, and limescale remover are classified as hazardous substances. The fact that you can buy them in a supermarket does not exempt them from COSHH. When these products are used in a workplace setting — particularly in larger quantities, in enclosed spaces, or where multiple products are used together — the risks can be significant.

The 6-Step COSHH Assessment Process

Carrying out a COSHH assessment does not require specialist training or expensive consultants. It is a logical, step-by-step process that any competent person can follow.

Step 1: Make an inventory of all hazardous substances

Walk through your workplace and list every substance that could be hazardous. Open every cupboard, check every shelf, and look in every van. Include:

• Products you use every day
• Products you use occasionally (seasonal treatments, specialist cleaners)
• Products that are stored but rarely used
• Substances generated by your work (dust, fumes, vapours)

Be thorough. It is better to list something that turns out to be low-risk than to miss something that could cause harm.

Practical tip: Take photos of product labels as you go. This saves time later when you need to record product names, manufacturers, and hazard classifications.

Step 2: Gather Safety Data Sheets (SDS) for each substance

For every chemical product on your list, you need the Safety Data Sheet. This is a standardised document (usually 8-16 pages) that contains detailed information about the product’s hazards, safe handling, storage requirements, and emergency procedures.

Where to get them:

• Ask your supplier. They are legally required to provide an SDS with every hazardous product they sell.
• Check the manufacturer’s website. Most manufacturers have SDS libraries available for download.
• Contact the manufacturer directly if you cannot find one online.

You do not need an SDS for substances like dust or fumes that are generated by your work process, but you do need to document the hazards they present (which are well-established and published by the HSE and HSA).

Step 3: Identify who is exposed and how

For each substance, work out:

• Who could be exposed? Employees, contractors, visitors, members of the public, cleaners working after hours?
• How could they be exposed? The main routes of exposure are:
  • Inhalation — breathing in vapours, fumes, dust, or mist
  • Skin contact — splashes, immersion, or contact with contaminated surfaces
  • Ingestion — swallowing (usually through contaminated hands or food)
  • Eye contact — splashes or vapours affecting the eyes
• How often and for how long? A brief, occasional exposure is very different from daily, prolonged use.

Step 4: Evaluate the risk level

Risk is determined by two factors:

• Severity — how serious could the harm be? (mild irritation vs. cancer vs. death)
• Likelihood — how probable is it that someone will actually be harmed, given the current controls?

You can use a simple risk matrix:

	Low Severity	Medium Severity	High Severity
Unlikely	Low risk	Low risk	Medium risk
Possible	Low risk	Medium risk	High risk
Likely	Medium risk	High risk	High risk

The SDS will tell you the severity. The likelihood depends on how the substance is used, how much is used, how often, and what controls are already in place.

Step 5: Decide on control measures

This is the most important step. For every substance that presents a risk, you need to decide what controls will reduce that risk to an acceptable level.

The law requires you to follow the hierarchy of controls, starting with the most effective:

1. Elimination — can you stop using this substance altogether?
2. Substitution — can you replace it with something less hazardous?
3. Engineering controls — can you use ventilation, extraction, or enclosed systems to reduce exposure?
4. Administrative controls — can you reduce exposure through procedures, training, or limiting the time people spend working with the substance?
5. Personal Protective Equipment (PPE) — gloves, masks, goggles, aprons

PPE should always be the last resort, not the first. We will cover this in more detail below.

Step 6: Record, implement, and review

Write everything down. Your COSHH assessment should be a clear, readable document that records:

• The substance and its hazards
• Who is at risk and how
• The risk level
• The control measures in place
• The date of the assessment
• Who carried it out
• When it will be reviewed

Then actually implement the controls you have identified. A COSHH assessment that sits in a drawer and never gets acted on is worthless — and will not protect you in an inspection or legal claim.

Review your assessments at least annually, or sooner if:

• You start using a new substance
• You change a process or method of work
• Someone reports symptoms or a health concern
• There is an incident or near-miss
• New information becomes available about a substance

Our compliance kits include pre-formatted COSHH assessment templates with common substances already listed for your trade. Just review, customise, and you are compliant.

Industry-Specific COSHH Examples

COSHH applies differently depending on your trade. Here are some common examples to help you identify what is relevant to your business.

Cleaning businesses

Cleaning is one of the industries where COSHH is most commonly overlooked — and most frequently needed. Here are some common cleaning chemicals and their hazard categories:

Product	Common Hazards	Main Exposure Route
Bleach (sodium hypochlorite)	Corrosive, irritant, toxic to aquatic life	Skin contact, inhalation
Degreasers	Irritant, may contain solvents	Skin contact, inhalation
Disinfectants	Irritant, sensitiser	Skin contact, inhalation
Oven cleaners	Corrosive (often contain sodium hydroxide)	Skin contact, eye contact
Window/glass cleaners	Irritant, may contain ammonia	Inhalation, eye contact
Limescale removers	Corrosive (often contain acids)	Skin contact, eye contact
Floor polish/strippers	Irritant, flammable	Skin contact, inhalation

Key risk: Mixing products. Never mix bleach with ammonia-based products or acid-based cleaners — the resulting fumes can be extremely dangerous.

Construction and trades

Tradespeople encounter a wide range of hazardous substances:

• Cement and concrete dust — highly alkaline; causes burns to wet skin and serious lung damage with prolonged inhalation
• Silica dust — generated when cutting concrete, stone, or brick; causes silicosis, a serious and irreversible lung disease
• Wood dust — hardwood dust is a known carcinogen; softwood dust causes irritation and asthma
• Solvents and thinners — used in painting, varnishing, and cleaning tools; harmful by inhalation and skin contact
• Adhesives — contact adhesives and epoxy resins can cause dermatitis and sensitisation
• Asbestos — while not strictly COSHH (it has its own regulations), awareness is critical for anyone working in buildings built before 2000

Beauty and grooming

Salons and barber shops use a surprising number of hazardous substances:

• Hair dyes and bleaching products — contain sensitisers that can cause severe allergic reactions
• Perming and relaxing solutions — contain strong chemicals including thioglycollic acid
• Nail products — acetone, acrylic monomers, and UV gel products are all classified as hazardous
• Cleaning and disinfecting products — used to sterilise tools and surfaces
• Aerosol products — hairsprays, dry shampoos, and colour sprays all produce inhalable mist

Landscaping and grounds maintenance

Outdoor work brings its own set of hazards:

• Herbicides and pesticides — can be harmful through skin contact, inhalation, and ingestion
• Petrol and diesel — flammable and harmful by inhalation
• Two-stroke fuel mix — contains solvents that are harmful through skin contact
• Oils and lubricants — prolonged skin contact can cause dermatitis
• Fertilisers — some are irritants or harmful if ingested

Understanding Safety Data Sheets (SDS)

Safety Data Sheets are the backbone of your COSHH assessment. They tell you everything you need to know about a substance’s hazards and how to handle it safely.

What is an SDS?

An SDS is a standardised document that provides detailed information about a chemical product. Under the REACH Regulation (which applies in both the UK and EU/Ireland), suppliers must provide an SDS for any product classified as hazardous.

The format is standardised internationally, so once you know how to read one SDS, you can read them all.

The 16 sections of an SDS

Every SDS follows the same structure:

1. Identification — product name, manufacturer, emergency contact
2. Hazards identification — classification and hazard statements
3. Composition/information on ingredients — what is in it
4. First-aid measures — what to do if someone is exposed
5. Fire-fighting measures — how to deal with a fire involving the product
6. Accidental release measures — how to clean up a spill
7. Handling and storage — safe working practices and storage conditions
8. Exposure controls/personal protection — workplace exposure limits and PPE requirements
9. Physical and chemical properties — appearance, odour, boiling point, etc.
10. Stability and reactivity — what it reacts with and what to keep it away from
11. Toxicological information — health effects data
12. Ecological information — environmental impact
13. Disposal considerations — how to dispose of it safely
14. Transport information — classification for transport
15. Regulatory information — applicable legislation
16. Other information — revision dates and additional notes

The four sections you really need for your COSHH assessment

You do not need to read every SDS cover to cover. For your COSHH assessment, focus on these four sections:

• Section 2: Hazards identification — tells you what the substance can do to you. Look for the hazard statements (H-statements) like “H314: Causes severe skin burns and eye damage” or “H335: May cause respiratory irritation.”

• Section 4: First-aid measures — tells you what to do if exposure occurs. This information goes straight into your emergency procedures.

• Section 7: Handling and storage — tells you the precautions to take during use and how to store the product safely. This informs your control measures.

• Section 8: Exposure controls/personal protection — tells you the workplace exposure limits (if any) and what PPE to use. This is critical for choosing the right gloves, masks, and other protective equipment.

Practical tip: Create a folder (physical or digital) for all your Safety Data Sheets. Keep them accessible to everyone who uses the products. During an inspection, one of the first things an inspector will ask for is your SDS file.

Control Measures in Detail

The hierarchy of controls is the cornerstone of COSHH compliance. It is a structured approach that prioritises the most effective controls first.

Elimination — stop using it

The most effective control is to remove the hazard entirely. Ask yourself: “Do we actually need to use this substance?”

Examples:

• Switching from a chemical cleaning process to a steam cleaning process
• Removing unnecessary products from your stock (how many different cleaners do you really need?)
• Changing a work process so that a hazardous substance is no longer required

Substitution — use something less hazardous

If you cannot eliminate the substance, can you replace it with a safer alternative?

Examples:

• Replacing solvent-based paints with water-based alternatives
• Using a less concentrated cleaning product
• Switching from a powdered product (which creates dust) to a liquid or gel
• Using pre-mixed products instead of mixing concentrates

Engineering controls — contain or extract

If you must use the substance, can you reduce exposure through physical measures?

Examples:

• Local exhaust ventilation (LEV) — extraction systems that capture fumes, dust, or vapours at the source (e.g., dust extraction on power tools, fume extraction in nail bars)
• Enclosed systems — using products in sealed or partially enclosed equipment
• General ventilation — ensuring adequate airflow in work areas
• Wet cutting — using water to suppress dust when cutting stone or concrete

Administrative controls — manage the exposure

These are the procedures, policies, and practices that reduce risk:

• Training — ensuring everyone knows what substances they are using, what the risks are, and how to handle them safely
• Safe working procedures — written instructions for using hazardous substances
• Rotation — limiting the time any one person spends working with a substance
• Housekeeping — regular cleaning to prevent build-up of dust or residues
• Health surveillance — monitoring the health of workers who are regularly exposed to certain substances (a legal requirement in some cases)
• Signage — clear labelling and warning signs in storage and use areas

PPE — the last resort

Personal Protective Equipment should only be relied upon when the controls above are not sufficient on their own. PPE is the least effective control because:

• It only protects the person wearing it
• It must be the right type for the specific hazard
• It must fit properly
• It must be worn correctly every single time
• It must be maintained and replaced regularly

Common PPE for chemical work includes:

• Gloves — the type matters; nitrile gloves protect against different chemicals than latex or PVC
• Eye protection — safety glasses for splashes, goggles for vapours or significant splash risk
• Respiratory protection — dust masks (FFP2/FFP3) for particulates, half-face or full-face respirators with appropriate filters for vapours and gases
• Protective clothing — aprons, overalls, or disposable coveralls depending on the substance
• Skin protection — barrier creams for some applications (though these should not be relied upon as a primary control)

Important: If you provide PPE, you must also provide training on how to use it, ensure it fits properly, maintain it in good condition, and replace it when necessary. Just handing someone a pair of gloves is not enough.

Common COSHH Mistakes

Even well-intentioned businesses get COSHH wrong. Here are the most frequent errors and how to avoid them.

1. Forgetting everyday chemicals

The number one mistake is only assessing the “obviously dangerous” substances and overlooking everyday products. Hand soap, washing-up liquid, air fresheners, marker pens, correction fluid, printer toner — these can all be classified as hazardous substances. Go through your entire workplace methodically and do not skip anything.

2. Not collecting Safety Data Sheets

You cannot complete a proper COSHH assessment without Safety Data Sheets. If your supplier has not provided them, ask. If they cannot provide them, find another supplier. An SDS is not optional — it is a legal requirement for the supplier to provide one.

3. Using PPE as the only control measure

This is extremely common, especially in small businesses. The conversation goes: “It’s a bit dangerous, so we wear gloves.” That is not COSHH compliance. You must demonstrate that you have considered the full hierarchy of controls before falling back on PPE.

4. Not training staff

A COSHH assessment is only useful if the people doing the work know about it. Every employee who works with hazardous substances must receive training on:

• What substances they are using and what the risks are
• How to use them safely
• What PPE to wear and how to wear it
• What to do in an emergency (spill, splash, overexposure)
• Where to find the Safety Data Sheets and COSHH assessments

5. Not reviewing when products change

Your COSHH assessments are living documents. If you switch cleaning product brands, start using a new adhesive, or change a work process, you need to review and update the relevant assessments. An outdated assessment is almost as bad as no assessment at all.

6. Storing the assessment and forgetting about it

A COSHH assessment that nobody has read, that staff do not know about, and that has not been reviewed in three years will not protect you — legally or practically. Keep your assessments accessible, refer to them regularly, and make them part of your induction process for new staff.

See what a properly completed COSHH assessment looks like — download our free sample.

Documentation Requirements

Getting the paperwork right is essential. Here is what you need to record and how long you need to keep it.

What to record

Your COSHH assessment documentation should include:

• The substance — name, manufacturer, and product identifier
• The hazards — from the SDS and product label
• Who is at risk — and how they might be exposed
• Current controls — what you are already doing
• Additional controls needed — what else needs to be put in place
• Risk rating — before and after controls
• Emergency procedures — what to do in case of a spill, splash, or overexposure
• Assessor details — who carried out the assessment and when
• Review date — when the assessment will next be reviewed

How long to keep records

The record retention requirements are important and sometimes overlooked:

• Standard COSHH assessments: Keep for a minimum of 5 years from the date of the last entry.
• Health surveillance records: If any of your employees undergo health surveillance (medical monitoring because of their exposure to hazardous substances), those records must be kept for 40 years from the date of the last entry. This is because some occupational diseases — particularly cancers and respiratory conditions — can take decades to develop.

In Ireland, similar retention periods apply under the Chemical Agents Regulations, and it is considered good practice to follow the same 40-year rule for health surveillance records.

Making records accessible

Your COSHH assessments must be accessible to:

• Employees who work with the substances
• Safety representatives and employee representatives
• Enforcement officers (HSE inspectors in the UK, HSA inspectors in Ireland)
• Anyone else who needs them — for example, contractors working on your site

In practice, this means keeping them in a known location (a folder in the office, a shared digital drive, or a dedicated section of your health and safety management system) and making sure everyone knows where they are.

For more information about how COSHH assessments fit into your overall compliance picture, see our health and safety compliance checklist and our guide to health and safety risk assessments.

Compliance Alignment

This guide covers obligations under:

• UK: Control of Substances Hazardous to Health Regulations 2002 (as amended), made under the Health and Safety at Work etc. Act 1974. Enforced by the Health and Safety Executive (HSE).
• Ireland: Safety, Health and Welfare at Work (Chemical Agents) Regulations 2001 (SI No. 619/2001), made under the Safety, Health and Welfare at Work Act 2005. Enforced by the Health and Safety Authority (HSA).

Both sets of regulations require employers and self-employed persons to assess the risks from hazardous substances, implement appropriate control measures, and maintain records.

Key Takeaways and Next Steps

COSHH compliance is a legal requirement, but it does not have to be a headache. Here is a summary of what you need to do:

1. Audit your substances. Walk through your workplace and list every hazardous substance — including the ones you think are harmless.

2. Collect your Safety Data Sheets. Contact your suppliers if you do not have them. You cannot complete a proper assessment without them.

3. Work through the 6-step process. Inventory, SDS, exposure, risk, controls, record. Take it one substance at a time.

4. Follow the hierarchy of controls. Eliminate and substitute before reaching for PPE. Document your reasoning.

5. Train your team. Everyone who works with hazardous substances must know the risks and the controls.

6. Review regularly. At least annually, and whenever something changes.

7. Keep your records. Five years minimum, 40 years for health surveillance.

If you are starting from scratch, the prospect of doing all of this for every substance in your workplace can feel daunting. That is exactly why we built our compliance kits.

Our Basic and Pro compliance kits include professionally structured COSHH assessment templates tailored to common trades — cleaning, construction, beauty, landscaping, and more. Each template comes pre-populated with the most common substances for your industry, with space to add your own. You fill in the specifics, print or save the document, and you have a compliant COSHH assessment ready for inspection.

It is not about cutting corners. It is about not having to start from a blank page.

Ready to get your COSHH assessments sorted? View our compliance kits or download a free sample to see exactly what you will get.