Hazardous substances are present in more workplaces than most people realise, from the cleaning products used in offices and schools to the chemical fumes generated on construction sites and in manufacturing plants. When these substances aren’t properly managed, the consequences for workers can be serious and long-lasting: skin conditions, respiratory disease, and in some cases, life-altering illness.
That’s where COSHH comes in. The Control of Substances Hazardous to Health (COSHH) Regulations set out clear legal duties for UK employers covering everything from how risks must be assessed to what training workers are entitled to receive. Yet despite being well-established law, COSHH remains one of the most inconsistently applied areas of workplace health and safety.
In 2026, with the Health and Safety Executive (HSE) placing greater emphasis on occupational health enforcement, employers can no longer afford to treat COSHH as a paperwork exercise. Failing to comply can lead to enforcement action, costly fines, and, more importantly, preventable illnesses caused by hazardous substances. This guide explains what the law requires, what effective COSHH training should include, and how employers can create a safer, legally compliant workplace.
What Is COSHH? A Clear Definition
COSHH stands for the Control of Substances Hazardous to Health. In practical terms, it refers to the UK regulatory framework set out under the Control of Substances Hazardous to Health Regulations 2002 that governs how employers must manage, assess, and control the risks posed by hazardous substances in the workplace.
The COSHH definition covers a wide range of materials: chemicals, fumes, dusts, vapours, mists, biological agents, and even certain gases. So whether you’re a salon owner using hair dyes, a construction manager overseeing concrete cutting, or a lab technician handling reactive compounds, COSHH applies to you.
In simple terms, COSHH helps employers identify hazardous substances, assess the risks they pose, and implement practical measures to prevent or reduce employee exposure. It also ensures that workers receive the information, instruction, and training they need to work safely.
A common variation on this is what is COSH – technically a typo, but the answer is the same. COSHH (with the double H for “Health”) is the correct term, and the second H matters because it distinguishes it from general safety and emphasises the health angle specifically.
COSHH Requirements: What the Law Actually Says
The COSHH Regulations 2002 set out several clear employer duties. Understanding these COSHH requirements is the starting point for any compliance effort.
Employers are legally required to:
- Identify all substances hazardous to health used or produced during work
- Carry out a COSHH assessment before work with those substances begins
- Prevent or adequately control exposure
- Ensure control measures are properly used and maintained
- Monitor exposure where necessary
- Carry out health surveillance where appropriate
- Provide employees with information, instruction, and COSHH training
It’s worth noting that “adequate control” doesn’t always mean eliminating the substance entirely. In many industries, that’s simply not practical. What the law requires is that employers reduce exposure to as low as reasonably practicable and, in some cases, below specific Workplace Exposure Limits (WELs) set by the Health and Safety Executive (HSE).
What Is a COSHH Assessment?
A COSHH assessment is a structured evaluation of the risks posed by hazardous substances in a given work environment. Completing a COSHH assessment isn’t optional—it’s a legal requirement for employers whose work involves hazardous substances.
What a COSHH Assessment Covers
A thorough assessment typically includes:
- The identity and properties of each hazardous substance
- Who might be exposed and under what circumstances
- How exposure might occur (inhalation, skin contact, ingestion)
- The likelihood and severity of harm
- Existing control measures and whether they’re sufficient
- Any need for health monitoring or PPE
For example, consider a small dental practice. During routine procedures, staff may be exposed to mercury (from older amalgam fillings), disinfectants, and airborne particles. A COSHH assessment for that environment would examine each substance individually, assess how and when staff encounter them, and determine what protective measures – ventilation systems, gloves, masks, and safe disposal protocols – are needed.
The assessment must be reviewed regularly and updated whenever there’s a significant change in substances used, working practices, or staffing.
COSHH Training: What Employers Must Provide
This is where many employers fall short. It’s one thing to complete a COSHH assessment, it’s another to ensure that the people actually handling substances understand the risks and know how to protect themselves.
What Is COSHH Training?
COSHH training is formal instruction provided to workers that covers:
- The substances they work with and the risks associated with them
- How to read and interpret COSHH symbols and safety data sheets
- The correct use of personal protective equipment (PPE)
- Emergency procedures in the event of a spill or exposure incident
- Proper storage, handling, and disposal of hazardous materials
- Who to report concerns to and when
The training must be relevant, specific, and proportionate to the risk. A warehouse worker who uses a heavy-duty cleaning product weekly needs more detailed instruction than an office worker who occasionally uses a standard desk spray, though both scenarios may technically fall under health & safety COSHH obligations.
COSHH Online Training: Is It Acceptable?
COSHH online training has become increasingly popular, particularly since 2020. For many roles, an online course can satisfy the training requirement, provided it covers the necessary content and is followed up with practical, site-specific instruction.
Online training works well for induction purposes or for low-risk environments. However, for higher-risk roles – chemical manufacturing, laboratory work, and agricultural settings – it should be supplemented with face-to-face training and supervised practical sessions.
The HSE does not endorse specific training providers, but employers must be able to demonstrate that any training provided is fit for purpose.
COSHH Symbols and Signage: Why They Matter
One of the most practical elements of hazardous substances training is learning to recognise and understand COSHH symbols, the standardised pictograms used on product labels and safety data sheets.
Key COSHH Symbols and Their Meanings
The UK follows the GHS (Globally Harmonised System) for chemical labelling, which uses diamond-shaped pictograms with red borders. Here’s a summary of the most common ones:
| Symbol Name | What It Indicates |
|---|---|
| 🔥 Flame | Flammable substances (liquids, gases, solids). |
| ☠️ Skull and Crossbones | Acutely toxic – can cause death even in small quantities. |
| ❗ Exclamation Mark | Harmful or irritant – less severe than toxic but still hazardous. |
| 👤 Health Hazard (Person Silhouette) | Serious long-term health risks, including carcinogens. |
| 🧪 Corrosion | Causes burns to skin or eyes; may corrode metals. |
| 🌳 Environment | Harmful to aquatic life. |
| 💥 Exploding Bomb | Explosive or reactive substances. |
| 🛢️ Gas Cylinder | Gases under pressure. |
| 🔥⭕ Flame over Circle | Oxidising substances – can intensify fire. |
Understanding COSHH symbols’ meanings is a core competency for any worker handling chemicals. Misidentifying a corrosive substance as merely irritant, for instance, could result in serious injury.
COSHH signage in the workplace should clearly mark storage areas, identify the substances present, and direct workers to relevant safety information. Proper signage is both a legal expectation and a practical safeguard.
COSHH Examples Across Different Industries
COSHH doesn’t just apply to labs and factories. The breadth of COSHH examples across everyday working environments might surprise you.
- Hairdressers and beauty salons: Bleaches, dyes, perming solutions, and acetone-based nail products all fall under COSHH. Salons must ensure adequate ventilation and provide appropriate gloves and masks.
- Construction sites: Silica dust from cutting or grinding concrete is a significant hazard. Prolonged inhalation can cause silicosis, a serious and irreversible lung condition. COSHH assessments must address dust suppression techniques and RPE (respiratory protective equipment).
- Healthcare settings: Disinfectants, sterilisation chemicals, anaesthetic gases, and biological fluids are all within scope. NHS trusts typically operate detailed COSHH management systems as part of their wider health and safety frameworks.
- Cleaning companies: Commercial cleaning products often contain bleach, solvents, or strong alkalis. Workers need training in dilution ratios, safe handling, and what to do if a product contacts the skin or eyes.
- Agriculture: Pesticides and herbicides are among the most tightly regulated substances under COSHH health and safety law. Farmers and contractors must complete specific training and, in some cases, hold licences before using certain products.
Building a COSHH Management System
For larger organisations or those operating in higher-risk environments, a standalone assessment and a one-off training session simply won’t cut it. What’s needed is a COSHH management system, an integrated, ongoing approach to managing hazardous substances.
A well-functioning COSHH management system typically includes:
- A substance inventory updated regularly
- A library of current safety data sheets (SDS) for every product
- A schedule for reviewing and refreshing COSHH assessments
- A training matrix showing which employees have completed what training and when
- Documented records of monitoring, health surveillance, and incidents
- A process for evaluating new substances before they’re introduced to the workplace
Technology has made this easier. Many companies now use digital platforms to store SDS documents, schedule training renewals, and generate audit trails, which is particularly useful when dealing with HSE inspections.
Common Mistakes Employers Make
Even well-intentioned employers get this wrong. Here are some of the most common pitfalls:
Using generic assessments. A COSHH assessment copied from a template or downloaded from the internet is not a legal COSHH assessment unless it’s been adapted to reflect your actual workplace, substances, and working practices.
Failing to update assessments. If you introduce a new cleaning product, change a process, or hire workers with different vulnerabilities (such as those with pre-existing respiratory conditions), your assessment must be reviewed.
Treating training as a tick-box exercise. Simply asking employees to read a PDF or sign a document is not sufficient. Effective COSHH training should include clear explanations, practical examples, opportunities to ask questions, and regular refresher training where appropriate.
Ignoring COSHH for “everyday” products. Many employers assume that common products – bleach, white spirit, even flour dust in bakeries – don’t need to be formally assessed. They do.
A COSHH Summary: The Employer's Core Obligations
| Obligation | Detail |
|---|---|
| Assess the risk | Carry out a suitable and sufficient COSHH assessment. |
| Prevent or control exposure | Use elimination, substitution, engineering controls, or personal protective equipment (PPE). |
| Maintain control measures | Inspect, test, and maintain all protective equipment and control measures. |
| Monitor exposure | Monitor workplace exposure where Workplace Exposure Limits (WELs) apply or health surveillance is required. |
| Inform and train employees | Provide relevant, role-specific, and documented COSHH training. |
| Keep records | Retain COSHH assessments, training records, inspection logs, and health surveillance records where applicable. |
Staying Compliant in 2026
The regulatory landscape around COSHH health and safety has not changed dramatically in recent years, but enforcement has. The HSE has placed increased emphasis on occupational lung disease, skin disorders, and cancers caused by workplace chemical exposure, particularly in construction, manufacturing, and healthcare.
In 2026, employers should also be aware of evolving guidance around:
- Engineered nanomaterials, which are used increasingly in coatings, electronics, and medical devices but present emerging health risks
- Reproductive toxins, where the HSE has tightened guidance on substances that may affect fertility or foetal development
- Stricter monitoring of Workplace Exposure Limits for substances like wood dust and respirable crystalline silica
Staying current with HSE guidance and maintaining a living COSHH management system, not a static folder of documents, is the best way to remain compliant and, more importantly, to keep your workers safe.
Conclusion
COSHH is far more than a legal obligation, it’s an essential part of protecting employees from preventable workplace illnesses and injuries. Whether your business operates in healthcare, construction, manufacturing, hospitality, education, or office environments, understanding and managing hazardous substances is vital for maintaining a safe workplace.
Regular COSHH assessments, effective control measures, and high-quality employee training help businesses remain compliant while creating a healthier working environment for everyone.
If you’re looking to strengthen your workplace compliance, a comprehensive COSHH Training course can help employees understand their responsibilities, recognise workplace hazards, and work confidently with hazardous substances.
FAQ:
Yes. Employers are legally required to provide suitable information, instruction and training for employees working with hazardous substances.
There is no fixed legal renewal period, but employers should provide refresher training whenever procedures change, new substances are introduced, or employees require additional support.
Yes. Online COSHH training is suitable for many workplaces when combined with site-specific instruction where necessary.
Employers are legally responsible for ensuring suitable COSHH assessments, control measures, and employee training are in place.
Yes. Business size doesn’t matter. Any employer using hazardous substances must comply with COSHH Regulations.
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