Dust may irritate the eyes and the respiratory system. General Information Zirconium Silicate contains small quantities of radioactive isotopes of Uranium and Thorium. The average concentrations in Endeka Ceramics’ Zirconium Silicate are 300 ppm of Uranium and 180 ppm of Thorium. The radioactivity of Zirconium Silicate is due to it's natural radionuclides which are not processed, and which have not been processed, in view of their radioactive, fissile or fertile properties. Work activities involving Zirconium Silicates are regulated under a specific regulation (Council Directive 96/29/EURATOM of 13 May 1996), which is different to that concerning radioactive substances. This Directive, establishes the need to assess the radiation exposure to which workers are or may be exposed. The radiation level established by the International Commission on Radiological Protection (ICRP) sets an annual radiation dose of 1 mSv over which physical surveillance of workers becomes required. This value has been adopted by the Commission of the European Communities. Studies commissioned by Endeka Ceramics have concluded that when workers exposure to Zirconium Silicate is continuous (2000 hours per year), the radiation dose may reach 1 mSv over the year. Inhalation Prolonged and/or massive exposure to respirable crystaline silica-containing dust may cause silicosis, a nodular pulmonary fibrosis caused by deposition in the lungs of fine respirable particles of crystalline silica. IARC Classification Group 1: human carcinogenic. Skin Contact Skin irritation is not anticipated when used normally. Eye Contact Particles in the eyes may cause irritation and smarting. Specific Effects Frequent inhalation of dust over a long period of time increases the risk of developing lung diseases