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EHS > RCS

Respirable Crystalline Silica

Crystalline silica (CS), which covers quartz, cristobalite and tridymite, is one of the major raw materials in the ferro-alloys and silicon Industry. CS flours have for many years been subject to self-classification and labelling by the industry as harmful with the label Xn and the risk phrases R48/20 (danger of serious damage to health by prolonged exposure through inhalation) under the Dangerous Substances Directive 67/548/EEC

In the framework of the CLP Regulation, quartz and cristobalite in their respirable form – hereafter named as “RCS” – have been considered for the purposes of classification.

Industry (under the coordination of the Industrial Minerals Association/IMA) notified the following classification in December 2010 for mixtures and substances containing RCS, whether in the form of an identified impurity, additive or individual constituent:

This classification is based on the four following pillars:

a) The health effects only appear at the workplace, not in the general environment.
b) Only the respirable fraction is dangerous.
c) Increased risk of lung cancer is not observed in all industrial circumstances studied.
d) Development of cancer, if at all, appears only to occur after the development of
silicosis/fibrosis.

RCS is currently the subject of discussion at regulatory level for  potential inclusion in the revision of the Carcinogenic Directive. The smelting industry is concerned about the potentially huge consequences of such a scenario, and has therefore signed a Position Paper with 19 other industry sectors advocating  the Chemical Agents Directive as the appropriate legal framework with a Binding Limit Value for RCS at 0.1 mg/m³: see attached position paper.