Most methods in this book involve chemicals, special apparatus, other scientific equipment, and field and laboratory operational procedures that can be hazardous, particularly if used by untrained staff or with unsuitable facilities. Moreover, while guidance is often offered, the method descriptions do not necessarily address all safety problems and related issues (including responsible disposal of all wastes) associated with their use. It is the responsibility of users of these methods to establish in advance appropriate safety and health practices, including any operational limitations faced by particular laboratories and their staff. The same applies to methods undertaken in the field.