COSHH Assessment vs Safety Data Sheet: What’s the Difference?
A safety data sheet and a COSHH assessment are related, but they are not the same thing. One tells you about the substance. The other considers how that substance is actually used in your workplace.
That distinction matters because simply having a folder full of safety data sheets does not necessarily mean the risks from hazardous substances have been properly assessed.
What is a safety data sheet?
A safety data sheet, often shortened to SDS, is provided by the supplier of a hazardous chemical or substance.
It contains information such as:
the identity of the substance;
its hazardous properties;
first-aid measures;
fire-fighting information;
handling and storage requirements;
exposure controls and personal protective equipment;
spill and disposal information.
It is an important source of information, but it is written for the product generally. It does not know how your business uses it.
What is a COSHH assessment?
A COSHH assessment considers the actual risk created by hazardous substances in your workplace under the Control of Substances Hazardous to Health Regulations.
It should consider not only what the substance is, but also:
how it is used;
how much is used;
how often people are exposed;
how exposure could occur;
who could be affected;
what controls are already in place;
whether those controls are sufficient;
what happens during spills, cleaning, maintenance or abnormal situations.
The assessment turns generic hazard information into something relevant to the way the substance is actually handled.
So what is the difference?
The simplest way to think about it is this:
A safety data sheet describes the substance.
A COSHH assessment considers the risk created by using that substance in your particular workplace.
They support each other, but one does not replace the other.
Is a safety data sheet enough on its own?
Usually not.
A safety data sheet may tell you, for example, that a product can cause skin irritation or respiratory harm. It cannot tell you whether your employees use 50 millilitres once a month or 50 litres every day, whether the process creates mist or vapour, whether extraction is provided, or whether employees are exposed during cleaning.
Those factors can make a huge difference to the real level of risk.
Does every chemical need a complicated COSHH assessment?
No.
The level of assessment should be proportionate to the risk.
A low-risk cleaning product used occasionally in small quantities may need only a simple assessment and basic controls. A substance used frequently in a process that generates fumes, dust or spray may need much more detailed consideration.
The aim should be sensible control of exposure, not paperwork for its own sake.
What about substances created by the work itself?
COSHH is not limited to chemicals that arrive in labelled containers.
Hazardous substances can also be generated by work activities, including:
welding fume;
wood dust;
metalworking mist;
silica dust;
process fumes;
biological agents.
In those cases, there may be no supplier safety data sheet at all. The business still needs to understand the hazard and control exposure appropriately.
What should a good COSHH assessment actually achieve?
A useful COSHH assessment should help somebody understand:
what the hazardous substance or exposure is;
who may be affected;
how exposure could occur;
what controls are required;
whether those controls are working;
what to do if something goes wrong.
If the document does not help people understand and control the real risk, it has probably become an administrative exercise rather than a useful assessment.
Common mistakes SMEs make
Some of the most common problems are:
keeping safety data sheets but carrying out no workplace-specific assessment;
copying supplier wording directly into a COSHH form;
relying on PPE without considering better controls first;
failing to consider substances generated by the process;
using outdated safety data sheets;
assessing individual chemicals without considering combined exposure;
completing the paperwork but not checking whether controls are actually used.
A technically complete form is not much use if it bears little resemblance to what happens on the shop floor
Need help with COSHH?
Midlands Compliance Services provides practical COSHH assessments for manufacturing, engineering and other SMEs, focusing on actual workplace exposure, proportionate controls and clear actions.