In certain organisations, particularly sections of manufacturing industry, quite specific activities may require a high degree of control, for e.g. testing plating solutions. This is especially important where an abnormal event is likely to have a significant adverse environmental impact. In such cases, precise operational control may be essential. However, the knowledge of information required will only be relevant to the immediate operator, and therefore it is necessary to disseminate this information. A series of work instructions might be produced which are all related to one procedure. The instructions should be referenced in the procedures but should not be reproduced within the procedure itself.