Maintain controls

All elements of your control measures must be checked and reviewed regularly to make sure they continue to be effective. These checks should be adequate to determine whether improvements are required and will include:

• maintaining plant and equipment – all ventilation equipment must be examined  and tested regularly by a competent person (someone who has the necessary skills, knowledge and experience to carry out the work safely). This may involve measuring the airflow or the pressures in the system, or air sampling in the workroom. In general, all LEV must be examined and tested every 14 months
• making sure systems of work are being followed and revising them if they are not working
• making sure personal protective equipment is suitable, used, properly fitted and (where appropriate) maintained

You may need specialist advice, particularly for potentially serious risks or processes that are difficult to control, from someone who is competent in that area of work, eg an occupational hygienist. The British Occupational Hygiene Society has more information.