What is L5?
L5 is the HSE's Approved Code of Practice (ACOP) and guidance document for the Control of Substances Hazardous to Health Regulations 2002 (COSHH). It provides practical advice on how employers can comply with their legal duties to protect workers and others from the health risks created by hazardous substances used at work.
COSHH covers a wide range of substances including chemicals, products containing chemicals, fumes, dusts, vapours, mists, nanotechnology, gases, biological agents, and germs that cause diseases such as leptospirosis or legionnaires' disease.
Who Needs This Document?
L5 is essential reading for:
- Employers in any industry where hazardous substances are used, produced, or encountered
- Health and safety managers responsible for chemical safety programmes
- Occupational health professionals managing health surveillance
- Small business owners using cleaning chemicals, paints, adhesives, or other hazardous products
- Property managers overseeing maintenance activities involving hazardous substances
- Safety representatives and trade union officials
Key Topics Covered
Risk Assessment
The document explains how to carry out a suitable and sufficient assessment of risks from hazardous substances, including:
- Identifying hazardous substances in your workplace
- Evaluating who might be harmed and how
- Deciding on precautions and control measures
- Recording and reviewing assessments
Workplace Exposure Limits (WELs)
Guidance on understanding and applying workplace exposure limits, which are the maximum concentrations of hazardous substances in workplace air that workers can be exposed to.
Control Measures
Detailed advice on implementing the hierarchy of control:
- Elimination or substitution of hazardous substances
- Engineering controls and enclosed systems
- Local exhaust ventilation
- Personal protective equipment as a last resort
Health Surveillance
Requirements for health surveillance programmes when there is a disease or adverse health condition associated with exposure, and when it is possible to detect the disease or condition.
Information, Instruction and Training
Employers must provide workers with suitable information, instruction, and training about the hazardous substances they work with and the precautions to take.
Legal Status
As an Approved Code of Practice, L5 has a special legal status. While failure to follow the ACOP is not itself an offence, if you are prosecuted for a breach of health and safety law, and it is proved that you did not follow the relevant provisions of the ACOP, a court will find you at fault unless you can show that you complied with the law in some other way.
The ACOP text appears in bold boxes throughout the document, clearly distinguishing it from the supporting guidance.
Why It Matters
Exposure to hazardous substances remains one of the most significant causes of occupational ill health in the UK. According to HSE statistics, thousands of workers develop occupational lung disease, skin disease, and cancer each year as a result of workplace exposures.
Proper implementation of COSHH:
- Protects employee health from both immediate and long-term effects
- Reduces sickness absence and associated costs
- Demonstrates legal compliance and due diligence
- Improves workplace conditions and employee confidence
- Avoids enforcement action and potential prosecution
For SMEs in particular, understanding and implementing COSHH requirements is crucial even when using common products like cleaning chemicals, paints, or adhesives that may seem harmless but can cause serious health effects over time.