Gain practical COSHH awareness to recognise hazardous substances, reduce exposure risks, and protect workplace health with confidence.
A COSHH risk assessment is a structured process used to identify hazardous substances, assess exposure risks, apply control measures, and protect workers from chemical-related harm. Every workplace that stores, handles, or produces hazardous substances needs a clear, repeatable process for managing that risk, and COSHH provides exactly that framework.
Hazardous substances in the workplace may include:
HSE's how to carry out a COSHH risk assessment page that hazardous substances are not limited to products already labelled as hazardous — harmful substances can also be produced during work activities such as sanding, tile cutting, or welding. This is why a proper COSHH assessment looks beyond the chemical cupboard and considers the tasks being carried out across the whole site.
This guide walks through what a COSHH risk assessment involves, why it supports workplace safety compliance internationally, and the first practical steps for identifying hazardous substances.
A COSHH assessment helps employers and safety teams understand:
HSE's COSHH guidance hub is a UK regulatory framework, but its structure works as a practical global model for hazardous substance risk control, regardless of where a business operates.
COSHH is widely associated with UK compliance, but the underlying principles match international chemical safety expectations found elsewhere. In the USA, OSHA's Hazard Communication Standard page requires chemical hazard classification, workplace chemical lists, labels, safety data sheets, and employee training. EU-OSHA also promotes the management of dangerous substances through prevention, awareness, and compliance-focused guidance.
For international workplaces, a strong COSHH compliance process can support chemical risk management across construction, manufacturing, healthcare, logistics, oil and gas, maintenance, cleaning, and laboratory environments.
A COSHH assessment is needed whenever workers may be exposed to hazardous substances through:
If any of these exposure routes or materials are present in your workplace, a COSHH assessment — or an equivalent hazardous substance risk assessment — should already be in place.
The first step in any COSHH assessment is building a hazardous substances register, sometimes called a chemical inventory list. This document should capture:
A well-maintained COSHH register is the foundation of the entire assessment. Without an accurate chemical inventory management system, it becomes difficult to track which substances need control measures, which staff need training, and which areas require monitoring.
Every hazardous substance should be backed by a Safety Data Sheet (SDS), sometimes still referred to as a Material Safety Data Sheet (MSDS). GHS labels and chemical hazard symbols on packaging provide an immediate visual warning, while the SDS itself gives the full picture.
SDS documents help users understand chemical hazards, exposure controls, emergency measures, PPE requirements, storage, disposal, and first aid information. Reviewing these documents thoroughly — not just filing them away — is essential to building an accurate COSHH assessment.
For further reference on chemical hazard and safety information for worker protection, see the ILO/WHO International Chemical Safety Cards.
Once hazardous substances are identified, the next step is assessing who could be exposed and how. This should cover:
HSE guidance says the assessment should consider exposure routes, frequency, duration, people who may be exposed, existing controls, and further actions needed. This step is where a chemical exposure risk assessment moves from paperwork to a genuine understanding of workplace chemical exposure and its potential health effects on real people carrying out real tasks.
With exposed groups identified, the assessment should evaluate the level and severity of risk. A simple evaluation framework should assess:
This step applies to common workplace scenarios such as dust exposure at work, silica dust exposure, wood dust COSHH, welding fumes COSHH, solvent exposure, cleaning chemicals COSHH, and chemical vapours exposure. Each of these carries a different exposure profile, so evaluating severity substance-by-substance is essential.
Control measures should follow the recognised hierarchy of control COSHH structure, working from the most effective option down to the least:
HSE's principles of good control practice under COSHH that PPE should not automatically be chosen first because it is less reliable than other control measures. A robust set of COSHH control measures — including chemical PPE and personal protective equipment for chemicals — should always sit at the bottom of this hierarchy, not the top.
A COSHH risk assessment form or COSHH assessment template should capture the following checklist:
HSE says employers with five or more employees must record the assessment, and even smaller employers benefit from writing down the steps taken to identify and control risks.
Documentation alone is not enough — workers need to understand and apply it. Training should cover:
OSHA's chemical safety guidance states that employers with hazardous chemicals must have labels and safety data sheets for exposed workers and train workers to handle chemicals appropriately.
A COSHH assessment is not a one-time document. It should be reviewed when:
HSE says COSHH assessments should be reviewed regularly and updated when there are workplace changes, accidents, near misses, or signs that controls may no longer be effective.
A COSHH risk assessment is more than a form. It is a practical system for preventing chemical exposure, improving workplace safety compliance, and protecting workers from long-term health risks.
To strengthen your knowledge of hazardous substances, chemical safety, SDS use, control measures, and COSHH compliance, enrol in our Hazardous Substances / COSHH Awareness course and build the confidence to manage chemical risks safely at work.
