COSHH - Achieving control

What you should be aiming for…

The COSHH Regulations are 'goal setting' and recognise the fact that risk cannot always be eliminated. The aim is therefore to reduce the risk of exposure to hazardous substances to a tolerable level. This is achieved using the COSHH hierarchy of control.

Overview of the COSHH hierarchy of control

Regulation 7 of COSHH requires you to consider a hierarchy of control measures to ensure that exposure to substances hazardous to health is adequately controlled. The levels of the hierarchy are listed in priority order and must be considered and applied in this order. Each level of the hierarchy should be applied in a way that is appropriate to the activity and consistent with the risk assessment and each should only be considered after consideration of the ones above it. Most situations require several levels of the hierarchy to be used in order to adequately control the risk associated with exposure. In this way, residual risks should be dealt with by the next level of the hierarchy.

The hierarchy of control is as follows:

Eliminate the use of the hazardous substance wherever possible - is it possible to replace it with a less hazardous substance for example?
Enclose the process to reduce the potential for exposure to the hazardous substance wherever possible;
Control the exposure of the substance at source using engineering means (such as local exhaust ventilation - LEV);
Provide adequate protective equipment (such as respiratory protective equipment - RPE).

Expected standards of control are greater for substances that are classed as sensitisors, carcinogens or are particularly toxic.

There is a legal requirement to have local exhaust ventilation thoroughly examined at least every 14 months, or as frequently as dictated by a competent person. The competent person should draw up a schedule of thorough examination, which could be more frequent than the minimum, taking into account the demands of the process (for example, LEV in dusty environments may require more frequent examination). Similarly, there is a requirement to ensure that RPE is maintained in a suitable condition to ensure continuing effectiveness.

Project findings

Higher levels of the hierarchy of control were too quickly dismissed. Careful thought is often required at the design stage of the process where full consideration can be given to reducing the potential for exposure for example. Retrospectively this is more difficult to achieve.
There was often poor justification for rejecting higher levels of the hierarchy and passing on to the lower levels. Rarely did we see an assessment justify why a higher level of control had not been used - you should explain why a higher level of control is not appropriate to the activity.
There was a tendency to focus on 'best fit' control - we often saw control measures that were the deemed to be the easiest to employ rather than those of higher priority in the control hierarchy. For example, we saw a heavy reliance on personal protective equipment (PPE) rather than local exhaust ventilation (LEV). PPE is convenient and easier to initially implement, but is not a reliable control measure. It always fails to danger; only protects the wearer; relies on employees being properly trained in its use and on them continuing to use it correctly; and requires continuing replacement and maintenance to remain effective.
We found that where COSHH was more prescriptive (for example the controls required with named substances), control measures were generally good.

The presentation given by Total, below provides a good overview of the ongoing improvements they have made in order to control exposure to benzene on a rail car loading gantry:

Total presentation [230kb]