Many conservators are not trained chemists and therefore health hazards encountered in a laboratory can cause serious problems unless adequate precautions are taken. This paper discusses the main health hazards and measures taken to reduce and possibly eliminate these hazards. The properties of the various chemicals used in a laboratory are discussed and a series of tables produced listing the compound and its hazard. This includes acids, alkalis, metals and metal salts, solvents, preservatives, pesticides, fungicides and synthetic resins.