Excess amalgam following the completion of a dental procedure. It may be either excess amalgam mix which has not come into contact with the patient (non-contact amalgam waste) or amalgam contaminated by a patient's bodily fluids ( contact amalgam waste). It may be present in chairside traps, vacuum pump filters, extracted restorations or teeth, amalgam separators, or discarded amalgam capsules. Amalgam waste is classed as hazardous in the European Waste Catalogue and is subject in England to the Hazardous Waste (England and Wales) Regulations (SI2005/894). Amalgam waste should be stored separately in an airtight and clearly labelled container distant from any heat source prior to disposal according to national guidelines or legislation. Commercially supplied storage containers usually contain a mercury vapour suppressant such as activated charcoal or an oxidizing agent used to convert the mercury to a less hazardous form.
http://www.defra.gov.uk/environment/waste/special/pdf/amalgamguidance2005.pdf Department of the Environment and Rural Affairs guidance document on waste disposal.
http://126.96.36.199/Amalgam%20Waste.pdf Proposed American National standard/American Dental Association Specification No.109: Procedures for storing dental amalgam waste and requirements for amalgam waste storage containers.