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” – are self-classified by Industry (under the coordination of the Industrial Minerals Association/IMA be it 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 has been added in the revised Carcinogenic Directive with as Binding Limit Value 0.1 mg/m³ which correspond to the Industry position.