WARNING!  contains free silica. Do not breathe dust. Breathing silica is dangerous, and may cause progressive, irreversible lung injury. Recent studies show that silica particles are so small that regular dust masks will not provide adequate protection from inhalation. ALWAYS wear a mask that is rated for use with investment. (See your catalog for high-efficiency half-mask and full-face respirators and HEPA filters.) Wear this protective mask when mixing and quenching investment. Keep your investing area spotlessly clean and well ventilated. Obtain the MSDS for investment products. Follow OSHA safety and health standards for handling silica (cristobalite).