The physical hazard classifications presented in the report are applicable to all three of the forms of copper metal evaluated. Although not an official GHS endpoint, Section 2.2 of the report discusses the combustible dust hazard of the three copper metal forms, because an evaluation of this hazard is required in the preparation of a safety data sheet in the United States. The overall assessment of the available literature does not support listing copper metal as a combustible dust hazard.
Copper massive, copper powder, and coated copper flakes are not classified for the following applicable GHS physical hazards: explosiveness; flammable solid; self-reactive substances and mixtures; pyrophoric solids; self-heating substances and mixtures; substances and mixtures that, when in contact with water, emit flammable gases; oxidizing solids; corrosive to metals; or desensitized explosives. A summary of the endpoints and details on the hazard classification decisions are provided in Table 2.2. of the report. The remaining eight GHS physical hazard endpoints (flammable gases, aerosols, oxidizing gases, gases under pressure, flammable liquids, pyrophoric liquids, oxidizing liquids, organic peroxides) were judged to be not applicable to these forms of copper metal.
Table 2.2 Summary of GHS Physical Hazard Classifications for Copper Metal and Justification
|Explosiveness||Not Classified||Absence of explosive functional groups/properties.|
|Flammable solid||Not Classified||Study with coated copper flakes found no burning when in contact with flame for 20 minutes (ECHA, 2018a). Supported by data for copper powder (ECHA, 2018a).|
|Self-reactive substances and mixtures||Not Classified||Absence of self-reactive functional groups/properties.|
|Pyrophoric solids||Not Classified||Copper powder is used to extinguish some combustible metal fires (e.g., lithium).|
|Self-heating substances and mixtures||Not Classified||No data available. Experience with copper metal forms indicates a lack of self-heating properties.|
|Substances and mixtures that, when in contact with water, emit flammable gases||Not Classified||Copper is not a metalloid. Finely divided copper will not react with water at standard temperature and pressure.|
|Oxidizing solids||Not Classified||Copper contains no oxygen, chlorine, or fluorine.|
|Corrosive to metals||Not Classified||No data available. Experience with copper metal forms indicates that they are not corrosive to metals.|
|Desensitized explosives||Not Classified||Absence of explosive functional groups/properties.|
Notes: GHS = Globally Harmonized System of Classification and Labelling of Chemicals (UN, 2017).