What does COSHH stand for?
COSHH stands for Control of Substances Hazardous to Health. The governing legislation is the Control of Substances Hazardous to Health Regulations 2002, which require employers and self-employed contractors to assess the risks from hazardous substances used or produced during work — and to put measures in place to control those risks.
A COSHH assessment is the documented record of that process: the substance involved, the risk it presents, who is exposed, how they are exposed, and what controls are in place to protect them.
Who needs to carry out a COSHH assessment?
Under the COSHH Regulations 2002, the duty applies to:
- Employers who use hazardous substances in the workplace, or whose employees are exposed to them
- Self-employed contractors who use or are exposed to hazardous substances during their work
- Principal contractors with overall responsibility for health and safety on a CDM 2015 project, where subcontractors' activities involve hazardous substances
In practical terms, if you are a contractor carrying out any of the following, you need a COSHH assessment:
- Applying solvents, adhesives, or sealants
- Using fuels, oils, or lubricants
- Working with cement, concrete, or lime-based materials
- Using wood preservatives, paints, or surface treatments
- Operating in environments where dust, fumes, or vapours are generated
- Using cleaning products containing bleach, acids, or other chemicals
- Working near processes that generate welding fume, silica dust, or wood dust
The key test is this: could any substance used, produced, or encountered during the work cause harm to health through inhalation, skin contact, ingestion, or absorption? If yes, a COSHH assessment is required.
What substances are covered by COSHH?
COSHH covers a broad range of substances — many of which are present on every construction site and are often overlooked. Common examples include:
Dusts and fibres
- Respirable crystalline silica (RCS) — generated by cutting, grinding, or drilling concrete, stone, and masonry
- Wood dust — from cutting, sanding, or routing timber
- Asbestos — covered by the Control of Asbestos Regulations 2012 (a separate but related regime)
Chemical substances
- Cement and cement-based products — cause occupational dermatitis and chemical burns
- Epoxy resins and hardeners — skin sensitisers and respiratory hazards
- Solvent-based adhesives and sealants — flammable and toxic if inhaled
- Isocyanates — found in some spray paints and foam products; a leading cause of occupational asthma
Biological agents
- Legionella bacteria — relevant for contractors working on water systems
- Leptospirosis (Weil's disease) — relevant for groundworks in contact with soil or standing water
Fumes
- Welding fume — classified as a human carcinogen by the International Agency for Research on Cancer
- Exhaust fumes — from plant and vehicles operating in poorly ventilated spaces
One of the most common misconceptions in UK construction is that COSHH only applies to "chemicals." Cement is one of the most hazardous substances on a typical building site — responsible for significant rates of occupational dermatitis — and it requires a COSHH assessment just like any solvent.
What must a COSHH assessment include?
Under Regulation 6 of the COSHH Regulations 2002, you must carry out a "suitable and sufficient" assessment of the health risks created by work with hazardous substances. The HSE's guidance sets out what this means in practice.
A compliant COSHH assessment must cover the following:
1. Substance identification
Name the specific substance and include its Safety Data Sheet (SDS) reference. The SDS — previously known as a Material Safety Data Sheet (MSDS) — is the document supplied by the manufacturer or supplier that details the substance's hazards, composition, and recommended handling precautions. Under REACH regulations, every hazardous substance must have an SDS, and you are required to have access to one before using it.
2. Hazard classification
Identify how the substance causes harm: is it toxic by inhalation? A skin sensitiser? A carcinogen? A corrosive? This information will be on the SDS under Section 2 (Hazard Identification) and Section 11 (Toxicological Information).
3. Who is at risk and how
Identify which operatives are exposed, how often, for how long, and by what route (inhalation, dermal contact, ingestion). Consider not just the person directly using the substance, but anyone working nearby who might be exposed to dust, vapour, or overspray.
4. Current control measures
Document the controls already in place, working through the COSHH hierarchy:
1. Eliminate the substance — substitute it for a less hazardous alternative where reasonably practicable
2. Reduce exposure — use the substance in a less hazardous form (e.g. wet rather than dry), or reduce the quantity used
3. Control at source — use local exhaust ventilation (LEV), on-tool extraction, or enclosed systems
4. General ventilation — ensure adequate background ventilation in the work area
5. Safe systems of work — procedural controls such as no eating or drinking near the work area, hygiene facilities
6. Personal Protective Equipment (PPE) — RPE, gloves, eye protection, and coveralls as a last line of defence, not the first
Note the hierarchy: PPE alone is not an adequate control for most hazardous substances. It is a supplementary measure, not a substitute for engineering controls.
5. Health surveillance requirements
For certain substances and occupational diseases, the COSHH Regulations require ongoing health surveillance — medical checks to detect early signs of harm. This applies where operatives are regularly exposed to substances known to cause conditions such as occupational asthma, dermatitis, or noise-induced hearing loss.
6. Emergency arrangements
For any substance that could cause acute harm — acids, alkalis, isocyanates, or substances in high concentrations — document what to do in the event of spillage, skin contact, inhalation, or ingestion. Cross-reference the SDS first aid procedures.
7. Assessor details and review date
The assessment must be signed by a competent person and dated. It must be reviewed when conditions change — new substance, new task, change in working method, or following any health incident.
COSHH assessment vs safety data sheet — what's the difference?
This is one of the most common areas of confusion.
A Safety Data Sheet (SDS) is a document produced by the manufacturer or supplier of a hazardous substance. It tells you what the substance contains, what hazards it presents, and how to handle it safely. You don't write the SDS — you receive it.
A COSHH assessment is a document you produce. It takes the information in the SDS and applies it to your specific workplace, your specific task, and your specific workforce. It is the record of your risk assessment under the COSHH Regulations.
You cannot use an SDS as a substitute for a COSHH assessment. They are separate documents serving different purposes.
COSHH assessments in construction: the five substances contractors most commonly miss
These are the substances that most often come up in HSE enforcement notices — not because contractors are unaware of them, but because they're treated as "everyday" materials rather than hazardous substances:
1. Cement — causes occupational dermatitis and chemical burns. Hexavalent chromium in cement is also a sensitiser. Requires glove policy and skin surveillance on regular use.
2. Diesel and fuel oils — skin contact over prolonged periods is a known carcinogen risk. Fume inhalation in enclosed spaces requires LEV or forced ventilation.
3. Silicone and polyurethane sealants — many contain isocyanates or other sensitisers. Use in unventilated spaces requires RPE.
4. Timber preservatives and wood stains — often contain biocides and solvents. Frequently applied by hand without adequate PPE.
5. General cleaning products — bleach, acid-based descalers, and solvent cleaners are routinely used on site without any COSHH assessment in place.
How to complete a COSHH assessment: step by step
1. Identify the substance — check the product label and locate the SDS from the supplier
2. Review the SDS — pay particular attention to Sections 2, 8, and 11 (hazard identification, exposure controls, and toxicological information)
3. Identify who is at risk — list the operatives directly involved and anyone in the vicinity
4. Assess the exposure — how long, how often, and by what route are they exposed?
5. Evaluate the current controls — are they adequate? Do they follow the COSHH hierarchy?
6. Identify further controls needed — what else is required to reduce exposure to an acceptable level?
7. Record the assessment — sign it, date it, and make it available to those affected
8. Brief operatives — toolbox talk before the task begins, covering the hazard and the controls
9. Review and update — whenever conditions change, or at a minimum annually
Download a COSHH assessment template — ready in 60 seconds
SafetyPod offers a professionally drafted, HSE-compliant COSHH assessment template that covers everything required under the COSHH Regulations 2002 — substance identification, SDS reference, exposure assessment, control hierarchy, health surveillance requirements, and assessor sign-off.
The template is fully editable in Word. Add your company name, the substance details, and your site information — and it's ready to use.
→ Download the COSHH Assessment Template — £3.99
If you're managing multiple substances across a project, you also need a COSHH Register — a single document that lists every hazardous substance on site, its SDS reference, and its associated assessment.
→ Browse all COSHH templates in the SafetyPod library
Frequently asked questions
Do self-employed contractors need a COSHH assessment?
Yes. The COSHH Regulations 2002 apply to self-employed persons who use hazardous substances in the course of their work, in the same way they apply to employers.
How long does a COSHH assessment take?
For a single common substance — cement, for example — a COSHH assessment using a good template should take no more than 20 minutes. The time is in gathering the SDS and thinking through the exposure scenario, not in the paperwork itself.
Does every substance on site need its own COSHH assessment?
Yes, if it meets the definition of a hazardous substance under the Regulations. A good COSHH register consolidates all your site assessments into one document so nothing gets missed.
Can I reuse a COSHH assessment from a previous job?
Only if the substance, the task, the work environment, and the operatives are the same. If any of those factors change, the assessment must be reviewed and updated.
What happens if I don't have a COSHH assessment?
Failure to carry out a COSHH assessment is a breach of the COSHH Regulations 2002. The HSE can issue an Improvement Notice requiring compliance within a set period, or in serious cases a Prohibition Notice stopping work immediately. In cases where illness has resulted, prosecution is possible.
Summary
A COSHH assessment is not a form-filling exercise. It is the documented evidence that you have identified the hazardous substances in your work, assessed how they could harm your operatives, and put proportionate controls in place. Under the COSHH Regulations 2002, it is a legal requirement — and it applies to far more materials than most contractors realise.
If you don't have COSHH assessments in place for the substances on your current project, the fastest way to get there is a professionally drafted template you can adapt to your specific job.
→ Download the COSHH Assessment Template — £3.99
Written by the SafetyPod team — NEBOSH-qualified H&S professionals with hands-on experience across UK construction, civil engineering, and facilities management. All content is written to current HSE guidance and CDM 2015 compliance.
Last reviewed: May 2026