Organic solvents are used to dissolve, suspend or extract other materials without a chemical change to either the solvent or the material. Typical examples are:
|
Acetone |
Ethyl acetate |
Methanol |
|
Methyl ethyl ketone (MEK) |
Perchloroethylene |
Butanol |
|
Isopropoyl alcohol (IPA) |
Methyl chloride |
Trichloroethylene |
|
Toluene |
Glycol ethers |
Styrene |
|
n-Hexane |
Xylene |
White spirit |
The principal effects of solvents are irritation to the skin, eyes and lungs, headaches, nausea, dizziness and light-headedness. Solvent exposure can impair people's co-ordination and this can lead to accidents and poor performance. The effect can vary from person to person and may be made worse by drinking alcohol. Very high exposures may cause unconsciousness and even death. Repeated or prolonged skin exposure may cause dermatitis.
Solvents can have a variety of characteristics which include being flammable, toxic, carcinogenic, highly volatile and reactive with other materials. This can increase the risks significantly and each solvent needs to be considered individually.
Where solvents are used simultaneously, it is very important to consider the overall effect. This may be additive and may need expert assistance to establish the true levels of risk. COSHH Essentials, can be a useful tool for initial assessments, particularly as it helps to estimate the quantity of substance that will be liberated into the atmosphere.
It is not uncommon for significant vapours and mists to be formed during a process that uses a solvent. This can result in sudden exposure to flammable and/or toxic atmospheres if correct procedures are not followed or if a control system doesn’t work properly.
Assessing the risk
Risk assessments for processes using solvents should consider the following:
- Does the solvent:
- adversely affect health?
- readily form a vapour?
- have a workplace exposure limit (WEL)?
- need biological monitoring?
- require health surveillance?
- For the process, do you know:
- the resulting exposure?
- how much is used?
- the duration of exposure?
- how often workers are exposed?
- If the solvent cannot be substituted with a safer alternative, can you:
- reduce the process temperature?
- reduce the surface area of the exposed solvent?
- reduce the amount of agitation?
- reduce the operator input?
- reduce the quantity of solvent used?
- cover or enclose open solvent containers when not in use?
- add or improve an effective control measure, e.g. process containment or local exhaust ventilation (LEV)?