Substance use 
It is not just about the substance but the assessment needs to consider factors associated with its
use.
- What is the substance being used for?
- How is the substance used or applied?
- How could exposure occur?
- How often is the substance used?
- How long is the substance used for?
- How many times is the substance used?
- Is the substance mixed with other substances?
Are there any by-products which are harmful?
Exposure Time
The concept of dose is familiar to many i.e. level of exposure combined with duration of exposure, and therefore the significance of exposure time. The basic concept is that any “assault” on the body by a harmful agent is immediately countered by the body’s natural defences. However, these defence mechanisms take time to respond.
If a low-level exposure occurs over a short finite time and then stops, the body has time to recover. (If one suffers an acute exposure to ammonia gas, for example, at the short-term exposure limit (STEL) WEL (3 times the longterm exposure limits (LTEL) WEL) for a short period, the lungs have time to clear the contaminant and recover from the incident and no ill-effects should be suffered.)
If a higher-level exposure occurs over a longer period of time, damage continues to occur which eventually overwhelms the body’s defences. The level and duration of the exposure is such that recovery is not possible because the body’s defences are not able to cope with the continued assault and there is no break from exposure to allow the body to recover.
Concluding thoughts
As you can see there are a wide range of factors to be considered when undertaking a COSHH assessment, it is important that workplace procedures are developed to assist the process but also give the assessor the ability to delve deeper where the risks dictate this. It is not just about copying out the safety data sheet and calling this a COSHH assessment, that will definitely not be deemed suitable and sufficient and will not protect your employees from long term ill health associated with chemical use.
Watch our ‘Take 5 Minutes for Health & Safety‘ video to find out more!
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