In March 2018, the EU Risk Assessment Committee (RAC) made a proposal for harmonized classification and labelling (CLH) of silicon carbide (SiC) fibres. This proposal has been approved by the European Commission on 19 May 2020 and will be applicable 18 month after the publication of this decision in the official journal of the EU on 19 November 2021.
The decision and the classification do not concern SiC crude and grain (CAS 409-21-2). Customers of SiCMa members buying crude and grain are therefore not affected by the new classification of SiC fibres.
SiC crude and grain has been extensively tested for the REACH registration dossier and is clearly classified as non-hazardous material.
The new classification for SiC fibres foresees that SiC fibres and cleavage fragments which fall within the World Health Organization (WHO) definition of a ‘fibre’ should be classified as carcinogenic 1B. The WHO defines ‘fibres’ as particles with a length of >5µm, a diameter of <3µm and an aspect ratio (length/diameter) of >3:1.
The decision is based on scientific studies for whiskers. Nevertheless, RAC took a decision for all particles falling under the WHO definition, irrespective whether or not they showed adverse effects. SiCMa disagrees with this decision from a scientific perspective. Scientific studies undertaken by SiCMa and other publicly available information indicate that a differentiated view on SiC fibres is required. None of the scientific studies, to our knowledge, showed evidence that cleavage fragments and short fibres have carcinogenic effects. Only very long fibres, so-called ‘whiskers’ (diameter <1µm, length >10µm; aspect ratio >10) which are produced in a different way than SiC crude and grains may be considered carcinogenic.
Unfortunately, a source of confusion might be that SiC fibres have the same CAS 409-21-2 as SiC crude and grain, although, this is a completely different material.