L5 — Control of Substances Hazardous to Health (HSE Approved Code of Practice)

What it is for

L5 is the Health and Safety Executive's Approved Code of Practice and guidance supporting the Control of Substances Hazardous to Health Regulations 2002 — the document behind much of the practical detail in our guide to COSHH assessments. Now in its sixth edition, published in 2013, it sets out practical guidance on identifying hazardous substances, assessing exposure, and choosing control measures, together with the additional duties that apply to carcinogenic and mutagenic substances, biological agents, and substances known to cause occupational asthma.

Approved Code of Practice status

An Approved Code of Practice carries a distinct legal standing under the Health and Safety at Work etc. Act 1974. Failing to follow an ACOP is not itself a criminal offence, but in proceedings where its provisions are relevant, a court may treat that failure as evidence of a breach of the underlying Regulations unless the employer can show the duty was met in some other, equally effective way. In practice this places an ACOP a step above ordinary guidance: departing from it is possible, but the burden then sits with the duty holder to show their alternative approach was just as good.

Scope and typical application

L5 is aimed at dutyholders, health and safety professionals and worker representatives across every sector where hazardous substances are used or created, not construction alone. It sits alongside the wider chemicals framework that COSHH operates within, including the REACH and CLP regimes governing how substances are classified and labelled, and gives specific attention to categories of substance that carry additional duties under the Regulations: carcinogens and mutagens, biological agents, and substances associated with occupational asthma.

How it relates to the COSHH guide

Our guide to COSHH assessments sets out, in plain terms, what a COSHH assessment involves and when one is required. L5 is the fuller reference behind that: the identification, exposure-assessment and control-hierarchy detail in HSE's own guidance on carrying out an assessment draws directly on it. Reading the guide first, and treating L5 as the reference for anyone drafting or reviewing an actual assessment, is the right order for most readers.

Status and currency

The sixth edition was published in 2013. As at the date this page was last checked, HSE's own publication page lists it as the current edition, with no notice of withdrawal or a further edition superseding it. HSE publishes it free of charge as a PDF, alongside a priced printed edition.